Stroke and traumatic brain injury lead to upper motor neuron syndrome,which is characterized by muscle spasticity or paresis of varying severity depending on the lesion’s location and extent.Current treatments are mo...Stroke and traumatic brain injury lead to upper motor neuron syndrome,which is characterized by muscle spasticity or paresis of varying severity depending on the lesion’s location and extent.Current treatments are mostly symptomatic with limited efficacy and significant side effects.Nerve transfer techniques,such as the contralateral L4 ventral root transfer in animal models and C7 root transfer in both animal and clinical studies,have been shown to reduce spasticity and improve function in upper motor neuron syndrome;however,they lack selectivity.Our hypothesis is that using a selective peripheral donor nerve from the contralateral side,rather than the entire nerve root,may represent an effective nerve transfer and provide a robust basis for future research on selective muscle reinnervation in upper motor neuron syndrome.Ten rats underwent a contralateral ulnar-to-ulnar nerve transfer procedure.Electrophysiological measurements were conducted twelve weeks post-surgery to assess successful reinnervation of the contralateral flexor carpi ulnaris muscle.Additionally,muscle biopsies of the reinnervated flexor carpi ulnaris were harvested to examine the muscle fiber type composition,cross-sectional area,and collagen content as well as compare them to naive counterparts.Axon quantification of the reinnervated nerves was also performed.All rats recovered uneventfully,maintaining the use of both paws post-surgery.Electrophysiological tests confirmed the successful reinnervation of the flexor carpi ulnaris muscle.Muscle fiber type composition,cross-sectional area,and collagen content did not show statistically significant changes.Axon counts indicated successful nerve regeneration without architectural disruption.In conclusion,we were able to demonstrate this novel contralateral nerve transfer model’s feasibility,reproducibility,and safety as well as achieve effective muscle reinnervation.This model provides a valuable tool for further research on selective muscle reinnervation and treatment of upper motor neuron syndrome,with potential implications for improving clinical outcomes in stroke and traumatic brain injury patients.展开更多
Debate over the benefits and harms of icing acute muscle injuries remains unresolved.Some contend that ice is ineffective or even harmful,while others promote cryotherapy as a universal remedy.Centrists,often academic...Debate over the benefits and harms of icing acute muscle injuries remains unresolved.Some contend that ice is ineffective or even harmful,while others promote cryotherapy as a universal remedy.Centrists,often academics,call for more high-quality randomized controlled trials(RCTs)to resolve the issue.This viewpoint reframes the debate around 3 key points:first,although ice produces analgesia,evidence for sustained pain relief,beyond the immediate post-treatment period.展开更多
Heart failure(HF)is a complex clinical syndrome that promotes high morbidity and multi-systemic damage.Skeletal muscle can be directly affected by HF through a loss of physical capacity and various inflammatory,hormon...Heart failure(HF)is a complex clinical syndrome that promotes high morbidity and multi-systemic damage.Skeletal muscle can be directly affected by HF through a loss of physical capacity and various inflammatory,hormonal,and metabolic mechanisms observed in this cardiac condition,which collectively contribute to a high prevalence of sarcopenia in HF patients.Therefore,the aim of this review was to compile the main recent clinical and epidemiological data on muscle health in HF patients.Nine studies were selected from systematic reviews and clinical trials,which demonstrated a high prevalence of sarcopenia in patients with HF,particularly in males,hospitalized patients,the elderly,and those with HF with reduced ejection fraction.Oxidative stress markers and higher levels of natriuretic peptides were also observed in HF patients who exhibited damaged muscle parameters.Furthermore,the overall deterioration of prognosis in HF was associated with criteria defining sarcopenia,such as low muscle strength and lean mass loss.These findings reinforce the importance of evaluating skeletal muscle in HF patients,which can provide improvements in morbidity and functionality.展开更多
Mechanical tension is widely recognized as the primary stimulus underlying the molecular mechanisms that influence muscle hypertrophy induced by resistance training.Despite this,several outdated or overstated concepts...Mechanical tension is widely recognized as the primary stimulus underlying the molecular mechanisms that influence muscle hypertrophy induced by resistance training.Despite this,several outdated or overstated concepts continue to persist,both in the scientific literature and in the practical application of resistance training coaching and program design.Claims that acute hormonal responses,metabolic stress,cell swelling or“the pump”meaningfully contribute to hypertrophy are not supported by scientific evidence.Additionally,the concept of sarcoplasmic hypertrophy as a distinct and functionally meaningful contributor to hypertrophy lacks strong evidence.In this review,we critically evaluate several persistent misconceptions and contrast them with evidence-based mechanistic insights into load-induced hypertrophy.Specifically,we discuss the role(or lack thereof)of systemic hormones,metabolites,and cell swelling in promoting muscle hypertrophy.We also critically review the concept of sarcoplasmic hypertrophy and propose that it is not a meaningful contributor to muscle hypertrophy.Lastly,to translate knowledge for trainees and coaches,we discuss the upper limit of muscle hypertrophy and provide readers with evidence-based,reasonable expectations for muscle hypertrophy.We aimed,through this review,to use scientific evidence to enhance our understanding of what drives muscle hypertrophy and provide an evidence-based framework for resistance exercise training.展开更多
BACKGROUND Perioperative anesthesia management of obese patients presents significant challenges as traditional total body weight-based dosing fails to achieve optimal anesthetic effects due to altered pharmacokinetic...BACKGROUND Perioperative anesthesia management of obese patients presents significant challenges as traditional total body weight-based dosing fails to achieve optimal anesthetic effects due to altered pharmacokinetic characteristics including abnormal drug distribution and clearance.Rocuronium exhibits markedly different distribution patterns in obese patients,with conventional weight correction methods inadequately addressing individual muscle mass variations that critically influence drug distribution.AIM To investigate the quantitative relationship between skeletal muscle index(SMI)and rocuronium distribution volume in obese colorectal cancer patients,establish a population pharmacokinetic model,and develop individualized dosing strategies based on muscle mass.METHODS A retrospective cohort study was conducted,including 100 obese patients(body mass index≥30 kg/m^(2))who underwent elective radical colorectal cancer surgery at our hospital from June 2023 to January 2025.Skeletal muscle mass was measured using InBody 260 body composition analyzer and SMI was calculated to assess muscle mass,with male SMI<7.0 kg/m^(2) and female SMI<5.7 kg/m^(2)as diagnostic criteria for sarcopenia.Plasma rocuronium concentrations were detected by liquid chromatography-tandem mass spectrometry/mass spectrometry,and nonlinear mixed-effect modeling was used to establish population pharmacokinetic modeling.Stepwise regression was used to screen covariates,and dosing regimens were optimized through Monte Carlo simulation.The primary endpoint was targeted plasma concentration achievement rate,and the secondary endpoint was postoperative residual muscle relaxation incidence.RESULTS Among 100 patients,35(35.0%)had sarcopenia and 65(65.0%)did not.Patients in the sarcopenia group were older(64.1±9.8 years vs 54.2±10.9 years,P<0.001)and had significantly lower SMI(6.2±0.8 kg/m^(2)vs 8.4±1.2 kg/m^(2),P<0.001).SMI showed strong positive correlation with rocuronium steady-state distribution volume(r=0.718,P<0.001)and moderate negative correlation with clearance(r=-0.502,P<0.001).A two-compartment population pharmacokinetic model was successfully established,with SMI being the most important covariate affecting central compartment distribution volume(△OFV=-41.2,P<0.001).Model validation showed bootstrap successful convergence rate of 92.3%,and 92.1%of observed values fell within prediction intervals in predicted concentration versus predicted concentration.The SMI-based individualized dosing regimen improved target exposure achievement rate from 82.0%in traditional regimen to 93.5%(P=0.009),and reduced postoperative residual muscle relaxation incidence from 13.0%to 3.5%(P=0.018).The sarcopenia group showed the most significant improvement in achievement rate,from 71.4%to 93.8%(P=0.017).CONCLUSION SMI shows strong correlation with rocuronium distribution volume in obese colorectal cancer patients and is a key factor affecting drug distribution.SMI-based individualized dosing strategies can significantly improve target exposure achievement rate and reduce postoperative residual muscle relaxation incidence,providing scientific evidence for precision anesthesia management in obese patients.展开更多
Muscle cell-powered biohybrid robots represent a transformative fusion of biological tissue engineering and robotics,offering unprecedented potential for biomedical applications targeted at drug delivery,regenerative ...Muscle cell-powered biohybrid robots represent a transformative fusion of biological tissue engineering and robotics,offering unprecedented potential for biomedical applications targeted at drug delivery,regenerative medicine,bioengineered heart patches,lab-on-a-chip devices,biosensors,and soft surgical tools.This review categorizes the currently available examples and further explores advanced biofabrication techniques that drive the development of biohybrid systems,with a focus on 3D bioprinting,electrospinning,micro/nano patterning,self-assembly,and microfluidic devices.These fabrication strategies facilitate precise cell alignment,enhance electrical and mechanical properties,and enable the seamless integration of biological components with engineered structures.By incorporating both cardiomyocytes and skeletal muscle cells,biohybrid robots achieve controlled actuation,autonomous movement,and adaptability to environmental stimuli.Furthermore,we discuss the latest optimization strategies in biofabrication,addressing key challenges such as scalability,biocompatibility,and functional integration.Biohybrid robots,including swimmers,actuators,and pumps,enable targeted drug delivery,assistive devices,and fluid transport in engineered tissues.Their integration with biological systems advances regenerative medicine,disease modeling,drug screening,and soft robotics.This review provides a comprehensive perspective on the state-of-the-art advancements and potential optimization in the fabrication techniques,paving the way for the next generation of biohybrid robotic systems.展开更多
Background:Calcium and vitamin D play crucial roles in muscle health and fat distribution.Both dietary intake and serum levels of calcium and vitamin D are commonly examined in relation to overall body health.Methods:...Background:Calcium and vitamin D play crucial roles in muscle health and fat distribution.Both dietary intake and serum levels of calcium and vitamin D are commonly examined in relation to overall body health.Methods:The United Kingdom Biobank(UKB)database was searched and analyzed.Dietary and serum calcium and vitamin D levels were extracted from the data to evaluate potential associations with body composition.Linear regression analysis,ordinal regression analysis,and interaction analysis were used to examine the associations between variables.Results:In the survey of over 50,000 individuals in the UKB,the frequency of low handgrip strength was higher among those with low dietary calcium intake at baseline.Furthermore,individuals with low serum vitamin D levels exhibited a higher prevalence of high body fat percentage(BFP)events.Notably,these influences were observed to persist for nearly 10 years.Moreover,the data suggested that serum vitamin D levels should exceed 50 nmol/L and the daily dietary calcium intake should be at least 1,000 mg to maintain the strength and keep a lower BFP(OR:0.68,95%CI:0.52-0.90,P=0.0057).Conclusions:These findings underscore the importance of increasing calcium and vitamin D intake and monitoring serum vitamin D levels for effective public health strategies.展开更多
Background: Post-workout supplementation has been used in athletes and recreational exercisers;however, responses between normal and overweight individuals on exercise performance and muscle recovery are less known.Me...Background: Post-workout supplementation has been used in athletes and recreational exercisers;however, responses between normal and overweight individuals on exercise performance and muscle recovery are less known.Methods: Normal and overweight young adult males(21 subjects/group) participated in resistance and fatiguing exercises before receiving post-workout supplements: placebo, coenzyme Q10(CoQ10), or sports drink in a crossover design. Resistance exercises included upper body exercise(bench press, upright row, and standing shoulder press) and lower body exercise(dead lift, back squat, and front squat) at 75% of one-repetition maximum(1 RM). Fatiguing exercise was performed on a cycle ergometer with 3 min of all-out effort at 3.5% of body mass. Participants consumed post-workout supplements within 10 min of exercise completion and repeated-bout exercise was performed 1 h later, followed by cardiovascular responses, urinary biomarkers, and delayed onset muscle soreness(DOMS) assessments.Results: There were effects of overweight on resistance exercise volume, critical power, fatigue index, and postexercise diastolic blood pressure(DBP). However, no differences in urinary biomarkers of muscle damage(potassium and creatinine) or DOMS between normal and overweight individuals. After supplementation, CoQ10 and sports drink increased resistance exercise volume regardless of body mass and increased critical power in the normal group. Additionally, CoQ10 supplementation was associated with a reduction in urinary biomarkers and DOMS in both groups.Conclusion: These findings are beneficial for sport scientists, nutritionists, and exercise physiologists in guiding post-workout supplementation with CoQ10 and sports drink to improve exercise performance and muscle recovery in normal and overweight individuals.展开更多
Purpose: This study aimed to explore the effects of a 10-week combined exercise regimen on immobilizationinduced muscle atrophy and elucidate the possible function of Protein arginine methyltransferase 1(Prmt1) in thi...Purpose: This study aimed to explore the effects of a 10-week combined exercise regimen on immobilizationinduced muscle atrophy and elucidate the possible function of Protein arginine methyltransferase 1(Prmt1) in this process.Methods: 8-week-old male C57BL/6J mice were carried out combined exercise for 10 weeks. One week before the end of the intervention, mice underwent cast immobilization. Additionally, to investigate the potential mechanism in exercise-induced protection of skeletal muscle, mice in the exercise preconditioning group were administered TC-E-5003(an inhibitor of Prmt1 enzymatic activity). Exercise performance, muscle mass, and the cross-sectional area(CSA) of muscle fibers were analyzed. Besides, Prmt1 and Sestrin1(Sesn1) were either overexpressed or inhibited in C2C12 myotubes to elucidate the underlying mechanism.Results: Exercise preconditioning not only significantly improved muscle mass and motor ability in immobilized mice but also inhibited excessive activation of degradation pathways and enhanced protein synthesis. Importantly, Prmt1 mediated the protective effects of exercise preconditioning on muscle atrophy. Mechanistically,Prmt1 regulated the p38 mitogen-activated protein kinase(p38)/activating transcription factor 2(ATF2)pathway, which modulates Sesn1 expression. Sesn1 acts as a downstream of Prmt1 and ATF2, contributing to the myoblast differentiation and skeletal muscle regeneration through AMP-Activated protein kinase α2(AMPKα2)/transcriptional co-activator PPAR-γ co-activator-1 α(PGC-1α) signaling pathway.Conclusions: Taken together, our results highlighted the effectiveness of exercise preconditioning in preventing muscle atrophy via the Prmt1-Sesn1 pathway.展开更多
Genetic improvement of meat production traits has always been the primary goal of pig breeding.Geographical isolation,natural and artificial selection led to significant differences in the phenotypes of meat productio...Genetic improvement of meat production traits has always been the primary goal of pig breeding.Geographical isolation,natural and artificial selection led to significant differences in the phenotypes of meat production traits between Chinese local pigs and Western commercial pigs.Comparative genomics and transcriptomics analysis provided powerful tools to identify genetic variants and genes associated with skeletal muscle growth.However,the number of available genetic variants and genes are still limited.In this study,a comprehensive comparison of transcriptomes showed that ribosomal protein S27-like(RPS27L)gene was highly expressed in skeletal muscle and up-regulated in Chinese local pigs when compared with Western commercial pigs.Functional analysis revealed that overexpression of RPS27L promoted myoblast proliferation and repressed differentiation in pig skeletal muscle cells.Conversely,the knockdown of RPS27L led to the inhibition of myoblast proliferation and the promotion of differentiation.Notably,a 13-bp insertion-deletion(InDel)mutation was identified within the RPS27L promoter,inserted in Chinese local breeds and predominantly deleted in Western commercial breeds.Luciferase reporter assay suggested this InDel modulated RPS27L expression by influencing transcription factor 3(TCF3)and myogenic differentiation antigen(MYOD)binding to the promoter.Furthermore,a positive correlation was observed between RPS27L expression and backfat thickness.Association studies demonstrated this InDel was significantly associated with the body weight of pigs at the age of 240 d.Together,our results suggested that RPS27L was a regulator of skeletal muscle development and growth,and was a candidate marker for improving meat production traits in pigs.This study not only provided a biomarker for animal breeding,but also was helpful for understanding skeletal muscle development and muscular disease in humans.展开更多
Objective:To investigate the effect of a water-soluble nacre extract derived from Pinctada fucata on skeletal muscle aging.Methods:Naturally aged C57BL/6J mice received nacre extract mixed in chow for 12 weeks.Forelim...Objective:To investigate the effect of a water-soluble nacre extract derived from Pinctada fucata on skeletal muscle aging.Methods:Naturally aged C57BL/6J mice received nacre extract mixed in chow for 12 weeks.Forelimb grip strength,hanging performance,and locomotor activity were assessed.Skeletal muscle remodeling and signaling were evaluated by histology and immunostaining for fibrosis,contractile-marker features,senescence-and DNA damage-associated markers,inflammatory signaling,and mitochondrial proteins.Oxidative status was assessed by determining antioxidant capacity,lipid peroxidation,and oxidative DNA damage.Transcriptomic profiling was also performed,and selected targets were validated by quantitative RT-PCR and immunostaining.In addition,differentiated C2C12 myotubes were exposed to doxorubicin and treated with nacre extract;senescence-associated β-galactosidase,DNA damage signaling,and cell viability were measured.Results:Nacre extract increased forelimb grip strength and showed a positive trend in hanging performance without altering spontaneous locomotion.It also reduced collagen deposition,preserved contractile-marker immunoreactivity,attenuated senescence-and inflammation-associated signals,and increased mitochondrial protein immunoreactivity.Oxidative DNA damage was notably reduced by nacre extract.Transcriptomics indicated modulation of stress/redox programs and increased neurotrophic tyrosine kinase receptor type 2 expression,which were supported by tissue-level validation.In C2C12 myotubes,nacre extract suppressed doxorubicin-induced senescence-associated phenotypes without loss of cell viability.Conclusions:Water-soluble nacre extract mitigates skeletal muscle aging through coordinated modulation of oxidative stress,inflammation,mitochondrial features,and cellular senescence.展开更多
Skeletal muscle injuries are prone to induce fatigue,decrease resistance and imbalances in the body.Although ovalbumin(OVA)has such biological effect as promoting tissue development and immunomodulation,its impact on ...Skeletal muscle injuries are prone to induce fatigue,decrease resistance and imbalances in the body.Although ovalbumin(OVA)has such biological effect as promoting tissue development and immunomodulation,its impact on repairing skeletal muscle injuries has been rarely reported.In this study,a mouse model of muscle injury was constructed and found that OVA significantly increased muscle weight,muscle thickness,and exercise capacity in muscle-injured mice.Meanwhile,OVA improved the morphology of muscle tissues by reducing serum levels of urea nitrogen,creatine kinase,and lactate dehydrogenase,as well as decreasing the levels of inflammatory factors interleukin(IL)-1β,tumor necrosis factor α,and IL-6,respectively.In addition,transcriptomic and metabolomic analyses revealed that OVA could enhance muscle tissue morphology by upregulating the phosphatidylinositol 3-kinase-protein kinase B signaling pathway and improving amino acid metabolism through the upregulation of Col11a2,Ccn2,Thbs1,Tnc,Klf2,Bcl2l1,Adh3a1,and Rsad1.The study provided a theoretical foundation for understanding the molecular mechanisms in OVA-aided muscle injury repair.展开更多
Resistance exercise has been confirmed to be important for maintaining muscle mass and function.However,despite considerable experimental studies,the underlying mechanisms still requires further investigation to be el...Resistance exercise has been confirmed to be important for maintaining muscle mass and function.However,despite considerable experimental studies,the underlying mechanisms still requires further investigation to be elucidated.Sestrin1 is a stress-inducible protein strongly associated with the occurrence and development of skeletal muscle dysfunction.Besides,oxidative stress is believed to be a major pathogenic mechanism in the development of skeletal muscle atrophy,whereas regular exercise training induces the endogenous antioxidative system and protects the body against adverse effects of oxidative stress.Nevertheless,whether Sestrin1 is involved in the amelioration of resistance exercise on muscle atrophy and the role of its antioxidant function in this process remains unknown.Here we show that six-week resistance exercise training significantly improved muscle function,muscle mass,and oxidative damage and maintained the level of Sestrin1 in dexamethasone-treated C57BL/6J mice.Mechanistically,Sestrin1 overexpression rescued protein degradation and oxidative stress in atrophied myotubes.Furthermore,an emerging regulator of cellular defense against toxic and oxidative insults,nuclear factor erythroid2–related factor 2(Nrf2)controls the basal and induced expression of an array of antioxidant response element–dependent genes to regulate the pathophysiological outcomes of oxidant exposure.In this study,we found that Nrf2 is a target of Sestrin1,and Nrf2 nuclear translocation is facilitated by Sestrin1.ML385(an Nrf2 inhibitor)treatment mitigated the regulatory effects of overexpression-Sestrin1.Therefore,Sestrin1 was involved in the process of resistance exercise against skeletal muscle atrophy,which may be closely related to its antioxidant capacity,revealing a potential therapeutic strategy for reducing the loss of skeletal muscle.展开更多
To perform various functions in the body,skeletal muscle is controlled and coordinated as a whole by nerves.However,there has been little research into whether the nerve control characteristics of different muscles ar...To perform various functions in the body,skeletal muscle is controlled and coordinated as a whole by nerves.However,there has been little research into whether the nerve control characteristics of different muscles are different,and the importance of these potential differences.In the present study,we used a three-dimensional imaging of solvent-cleared organ-compatible multi-tracer technique to explore the spatial distribution patterns of sensory and sympathetic neurons that innervate limb muscles.We integrated transcriptome sequencing datasets from mouse limb muscles in public databases and performed correlation analysis with neuronal spatial distribution data to reveal the unique effects of different types of neurons on muscle functional pathways.In terms of spatial distribution patterns,sympathetic neurons exhibited a more concentrated distribution than sensory and motor neurons.In addition,the neuronal innervation of limb muscles exhibited four different characteristics:sympathetic neuron-rich muscle,sensory neuron-rich muscle,neuron-sparse muscle,and motor neuron-rich muscle.Sensory neuron density was mainly associated with muscle contractile structure and cell pH,whereas sympathetic neuron density was associated with protein kinase activity,muscle vasculature,muscle calcium-dependent protein kinase activity,lipid transport,and vesicle release.Motor neuron density was mainly associated with protein kinase activity,cell adhesion,oxidoreductase activity,and exocytosis.These findings may contribute to a deeper understanding of how nerves cooperate to endow muscles with diverse physiological functions,thereby providing new insights and experimental evidence for the treatment of various neuromuscular diseases.展开更多
Purpose:ATLAS is a cross-sectional study aiming to investigate environmental and genetic determinants of athletic performance in healthy Greek competitive athletes(CA).This article presents the study design,investigat...Purpose:ATLAS is a cross-sectional study aiming to investigate environmental and genetic determinants of athletic performance in healthy Greek competitive athletes(CA).This article presents the study design,investigates the muscle strength performance(MSP)of 289 adult and teenage CA,exercisers,and physically inactive individuals(PI),and proposes predictive models of MSP for adults.Methods:Muscle maximal,speed,and explosive strength(MMS/MSS/MES)at unilateral maximal concentric flexion and extension contraction(FC/EC)were evaluated using Biodex System 3 PRO^(TM)at 60°/s,180°/s,and 300°/s,while additional performance markers were assessed through field ergometric testing.Participants were interviewed about their lifestyle,dietary habits,physical activity,injury,and medical history.Body composition was assessed via bioelectrical impedance.gDNA was extracted from biochemical samples and then genotyped.Statistical analysis was conducted using IBM SPSS Statistics v21.0 and R.Results:Age,fitness,and sex impacted correlations of MSP with body composition and anthropometric measurements(p<0.05).Among CA,females outperformed males in accuracy(p<0.001)while,males outperformed females in anaerobic power,MSP,speed,and endurance(p<0.001).Adult CA outperformed exercisers and PI in MMS,MSS,and MES(p<0.05).Multiple linear regression models,with predictors age,FFM,body extremity,training load explained the majority of variation in MMS(R^(2)_(adj):71.4%–88.9%),MSS(R^(2)_(adj):64.8%–78.4%),and MES(R^(2)_(adj):52.7%–68.4%)at EC,FC,and their mean(p<0.001).Conclusions:Muscle-strengthening strategies should be customized according to individual fitness levels,body composition,and anthropometric measurements.The innovative sex-specific regression models assessing MMS,MSS,and MES at EC and FC provide a framework for personalizing rehabilitation and skill-specific training strategies.展开更多
Objectives:Postmenopausal women with stress urinary incontinence(SUI)exhibit low androgen expression.This study aimed to evaluate the efficacy and safety of vaginal androgen combined with pelvic floor muscle training(...Objectives:Postmenopausal women with stress urinary incontinence(SUI)exhibit low androgen expression.This study aimed to evaluate the efficacy and safety of vaginal androgen combined with pelvic floor muscle training(PFMT)in the treatment of SUI in postmenopausal women.Methods:Postmenopausal women with SUI were recruited from Hainan West Central Hospital between January 2024 and March 2025.Participants were randomly assigned in a double-blind manner to receive either vaginal androgen cream combined with PFMT(treatment group)or a visually identical placebo cream(without androgens)combined with PFMT(control group).The vaginal cream was applied to the vaginal wall at a dose of 0.5 g per application,twice weekly for a total of 10 applications,while PFMT was conducted for 8 weeks.The clinical efficacy and safety were compared between the two groups.Results:A total of 61 patients were finally enrolled,with 31 in the treatment group and 30 in the control group.At both 3-month and 6-month follow-ups,the treatment group demonstrated significantly lower values in daily pad usage(p<0.05),24-h pad test scores(p<0.05),and ICIQ-UI SF scores(p<0.05)compared to the control group.The improvement rate of urinary incontinence was significantly higher in the treatment group(p<0.05).Compared to baseline,the treatment group showed statistically significant reductions in all three outcome measures(all p<0.05).No severe adverse events were reported in either group during the treatment period.Conclusions:Androgen therapy combined with PFMT significantly improved the urinary incontinence remission rate in postmenopausal women with SUI,with no severe adverse effects observed.These findings suggest that androgen therapy may represent a novel therapeutic approach for SUI management in postmenopausal women.展开更多
Skeletal muscle accounts for approximately 40%of body mass and 50%–75%of whole-body protein,playing a central role in meat production and quality.Efficient protein synthesis in skeletal muscle relies on an adequate s...Skeletal muscle accounts for approximately 40%of body mass and 50%–75%of whole-body protein,playing a central role in meat production and quality.Efficient protein synthesis in skeletal muscle relies on an adequate supply of nutrient substrates and a balanced amino acid profile.Branched-chain amino acids(BCAA),including leucine(Leu),isoleucine(Ile),and valine(Val),are the most abundant essential amino acids in skeletal muscle and contribute to both protein synthesis and oxidative energy production.Additionally,BCAA function as signaling molecules that regulate gene expression and protein phosphorylation cascades,which significantly influence physiological processes,such as protein synthesis and degradation,glucose and lipid metabolism,and cell apoptosis and autophagy.These processes are primarily mediated through the PI3K/AKT/AMPK/mTOR signaling pathways.This review summarizes BCAA transporters and catabolic metabolism,their role as signaling molecules in regulating protein metabolism and glucose and lipid equilibrium,and applications in animal production.These findings offer both theoretical insights and practical guidelines for the precise regulation of feed efficiency and production performance through tailored dietary BCAA supplementations.展开更多
Background Heat shock proteins(HSPs)are key molecular chaperones that help maintain protein homeostasis by stabilizing or removing damaged proteins during cellular stress.Aging weakens these stress–response systems,d...Background Heat shock proteins(HSPs)are key molecular chaperones that help maintain protein homeostasis by stabilizing or removing damaged proteins during cellular stress.Aging weakens these stress–response systems,disrupting proteostasis and increasing vulnerability to sarcopenia.High-intensity training(HIT)can counteract these declines by activating protective pathways such as the HSP response.HSPs are highly responsive to stress,examining their regulation during aging is important,as altered HSP activity is linked to the progressive loss of muscle mass.Methods This study investigated the abundance and phosphorylation of HSPs in skeletal muscle from healthy,active young and older adults(n=7 per group),assessed at baseline and again in the older group following 12 weeks of HIT.Using calibrated Western blotting on both whole-muscle homogenates and pooled single muscle fibres,we quantified HSP content and phosphorylation to determine how aging and exercise influence stress–responsive protein regulation at both the tissue and cellular levels.Results In whole muscle homogenates,HSPs(HSP72,HSP27,andαB-crystallin)did not differ between young and older adults,while higher phosphorylation of small HSPs(sHSPs):phospho-HSP27 at Serine15(pHSP27 Ser15)and phospho-αB-crystallin at Serine59(pαB-crystallin Ser59)(∼1.8-fold and∼2.9-fold,respectively)were found in muscle from older adults,indicating higher cellular stress associated with aging.A 12-week HIT intervention in older adults reduced homogenate pHSP27 Ser15 and pαB-crystallin Ser59 abundances to similar levels found in young adults.Total HSPs typically displayed a distinct fiber-type profile in both age groups,with more in type I compared to type II fibers,distinguished by the presence of myosin heavy chain I(MHCI)or MHCII.Phosphorylation at pHSP27 Ser15 and pαB-crystallin Ser59 was not different between type I and type II fibers.The HIT in older adults decreased total and phosphorylated sHSPs in both type I and type II fibers but increased HSP72 in type I fibers.Conclusion HIT has the potential to mitigate age-related cellular stress and modulate protein expression patterns in aging skeletal muscle and,perhaps,has the potential to delay age-related muscle decline,thereby improving muscle health in older adults.展开更多
Background Intrinsic and extrinsic foot muscles contribute to foot and lower limb function.This knowledge provides opportunities to target these muscles in exercise and rehabilitation.However,a barrier is the limited ...Background Intrinsic and extrinsic foot muscles contribute to foot and lower limb function.This knowledge provides opportunities to target these muscles in exercise and rehabilitation.However,a barrier is the limited understanding of how prescribed exercises affect muscle activation and force output.This study examined muscle activation and torque production about the metatarsophalangeal joints of intrinsic and extrinsic foot muscles during common foot strengthening exercises.The secondary aim was to determine whether the addition of a postural change(leaning forward)or addition of mass can further increase muscle activation and torque.Methods Fifteen healthy participants(9 males,6 females;age=36.5±8.0 years,mean±SD)participated.Muscle activation was measured using fine-wire electromyography(EMG)electrodes for 2 intrinsic and 2 extrinsic muscles,and surface EMG electrodes for 4 superficial muscles.Metatarsophalangeal joint torque was measured using a custom toe dynamometer.Participants attended one 90-min session and performed 16 exercises.Five included the addition of leaning forward and 3 the addition of mass(20%of participant’s mass)to compare their effects on muscle activity and torque.Results Muscle activation and metatarsophalangeal joint torque varied considerably across exercises.Both the addition of leaning forward and the addition of mass increased muscle activation and metatarsophalangeal joint torque,with the addition of leaning forward producing a 35%median increase in torque about the metatarsophalangeal joints.Conclusion Many common exercises,despite high muscle activation,produce relatively low metatarsophalangeal joint torque,raising questions about their clinical value.Adding a forward lean significantly increases toe flexor muscle activity and torque,reaching levels greater than added mass and comparable to walking.展开更多
Amyotrophic lateral sclerosis(ALS)is a progressive neurodegenerative disease marked by motor neuron(MN)degeneration,neuromuscular junction disruption,and muscle atrophy,ultimately leading to paralysis and death.Despit...Amyotrophic lateral sclerosis(ALS)is a progressive neurodegenerative disease marked by motor neuron(MN)degeneration,neuromuscular junction disruption,and muscle atrophy,ultimately leading to paralysis and death.Despite extensive research,no effective treatment exists,highlighting the need to elucidate mechanisms driving ALS pathogenesis.About 90%of ALS cases are sporadic ALS and lack a clear genetic cause;the remaining 10%are familial ALS,associated with mutations in over 25 genes.The most common mutations are in superoxide dismutase 1(SOD1)and C9ORF72,with rarer variants in FUS,TARDBP,TBK1,and VCP.展开更多
基金supported by the European Research Council(ERC)under the European Union’s Horizon 2020 Research and Innovation Programme,No.810346.
文摘Stroke and traumatic brain injury lead to upper motor neuron syndrome,which is characterized by muscle spasticity or paresis of varying severity depending on the lesion’s location and extent.Current treatments are mostly symptomatic with limited efficacy and significant side effects.Nerve transfer techniques,such as the contralateral L4 ventral root transfer in animal models and C7 root transfer in both animal and clinical studies,have been shown to reduce spasticity and improve function in upper motor neuron syndrome;however,they lack selectivity.Our hypothesis is that using a selective peripheral donor nerve from the contralateral side,rather than the entire nerve root,may represent an effective nerve transfer and provide a robust basis for future research on selective muscle reinnervation in upper motor neuron syndrome.Ten rats underwent a contralateral ulnar-to-ulnar nerve transfer procedure.Electrophysiological measurements were conducted twelve weeks post-surgery to assess successful reinnervation of the contralateral flexor carpi ulnaris muscle.Additionally,muscle biopsies of the reinnervated flexor carpi ulnaris were harvested to examine the muscle fiber type composition,cross-sectional area,and collagen content as well as compare them to naive counterparts.Axon quantification of the reinnervated nerves was also performed.All rats recovered uneventfully,maintaining the use of both paws post-surgery.Electrophysiological tests confirmed the successful reinnervation of the flexor carpi ulnaris muscle.Muscle fiber type composition,cross-sectional area,and collagen content did not show statistically significant changes.Axon counts indicated successful nerve regeneration without architectural disruption.In conclusion,we were able to demonstrate this novel contralateral nerve transfer model’s feasibility,reproducibility,and safety as well as achieve effective muscle reinnervation.This model provides a valuable tool for further research on selective muscle reinnervation and treatment of upper motor neuron syndrome,with potential implications for improving clinical outcomes in stroke and traumatic brain injury patients.
文摘Debate over the benefits and harms of icing acute muscle injuries remains unresolved.Some contend that ice is ineffective or even harmful,while others promote cryotherapy as a universal remedy.Centrists,often academics,call for more high-quality randomized controlled trials(RCTs)to resolve the issue.This viewpoint reframes the debate around 3 key points:first,although ice produces analgesia,evidence for sustained pain relief,beyond the immediate post-treatment period.
文摘Heart failure(HF)is a complex clinical syndrome that promotes high morbidity and multi-systemic damage.Skeletal muscle can be directly affected by HF through a loss of physical capacity and various inflammatory,hormonal,and metabolic mechanisms observed in this cardiac condition,which collectively contribute to a high prevalence of sarcopenia in HF patients.Therefore,the aim of this review was to compile the main recent clinical and epidemiological data on muscle health in HF patients.Nine studies were selected from systematic reviews and clinical trials,which demonstrated a high prevalence of sarcopenia in patients with HF,particularly in males,hospitalized patients,the elderly,and those with HF with reduced ejection fraction.Oxidative stress markers and higher levels of natriuretic peptides were also observed in HF patients who exhibited damaged muscle parameters.Furthermore,the overall deterioration of prognosis in HF was associated with criteria defining sarcopenia,such as low muscle strength and lean mass loss.These findings reinforce the importance of evaluating skeletal muscle in HF patients,which can provide improvements in morbidity and functionality.
基金supported this work,but the SMP acknowledges support from the Canada Research Chairs Program(CRC-2021-00495)MJL is supported by a Canadian Institutes of Health Research(CIHR)Postdoctoral Fellowship award(Funding Reference No.187773).
文摘Mechanical tension is widely recognized as the primary stimulus underlying the molecular mechanisms that influence muscle hypertrophy induced by resistance training.Despite this,several outdated or overstated concepts continue to persist,both in the scientific literature and in the practical application of resistance training coaching and program design.Claims that acute hormonal responses,metabolic stress,cell swelling or“the pump”meaningfully contribute to hypertrophy are not supported by scientific evidence.Additionally,the concept of sarcoplasmic hypertrophy as a distinct and functionally meaningful contributor to hypertrophy lacks strong evidence.In this review,we critically evaluate several persistent misconceptions and contrast them with evidence-based mechanistic insights into load-induced hypertrophy.Specifically,we discuss the role(or lack thereof)of systemic hormones,metabolites,and cell swelling in promoting muscle hypertrophy.We also critically review the concept of sarcoplasmic hypertrophy and propose that it is not a meaningful contributor to muscle hypertrophy.Lastly,to translate knowledge for trainees and coaches,we discuss the upper limit of muscle hypertrophy and provide readers with evidence-based,reasonable expectations for muscle hypertrophy.We aimed,through this review,to use scientific evidence to enhance our understanding of what drives muscle hypertrophy and provide an evidence-based framework for resistance exercise training.
文摘BACKGROUND Perioperative anesthesia management of obese patients presents significant challenges as traditional total body weight-based dosing fails to achieve optimal anesthetic effects due to altered pharmacokinetic characteristics including abnormal drug distribution and clearance.Rocuronium exhibits markedly different distribution patterns in obese patients,with conventional weight correction methods inadequately addressing individual muscle mass variations that critically influence drug distribution.AIM To investigate the quantitative relationship between skeletal muscle index(SMI)and rocuronium distribution volume in obese colorectal cancer patients,establish a population pharmacokinetic model,and develop individualized dosing strategies based on muscle mass.METHODS A retrospective cohort study was conducted,including 100 obese patients(body mass index≥30 kg/m^(2))who underwent elective radical colorectal cancer surgery at our hospital from June 2023 to January 2025.Skeletal muscle mass was measured using InBody 260 body composition analyzer and SMI was calculated to assess muscle mass,with male SMI<7.0 kg/m^(2) and female SMI<5.7 kg/m^(2)as diagnostic criteria for sarcopenia.Plasma rocuronium concentrations were detected by liquid chromatography-tandem mass spectrometry/mass spectrometry,and nonlinear mixed-effect modeling was used to establish population pharmacokinetic modeling.Stepwise regression was used to screen covariates,and dosing regimens were optimized through Monte Carlo simulation.The primary endpoint was targeted plasma concentration achievement rate,and the secondary endpoint was postoperative residual muscle relaxation incidence.RESULTS Among 100 patients,35(35.0%)had sarcopenia and 65(65.0%)did not.Patients in the sarcopenia group were older(64.1±9.8 years vs 54.2±10.9 years,P<0.001)and had significantly lower SMI(6.2±0.8 kg/m^(2)vs 8.4±1.2 kg/m^(2),P<0.001).SMI showed strong positive correlation with rocuronium steady-state distribution volume(r=0.718,P<0.001)and moderate negative correlation with clearance(r=-0.502,P<0.001).A two-compartment population pharmacokinetic model was successfully established,with SMI being the most important covariate affecting central compartment distribution volume(△OFV=-41.2,P<0.001).Model validation showed bootstrap successful convergence rate of 92.3%,and 92.1%of observed values fell within prediction intervals in predicted concentration versus predicted concentration.The SMI-based individualized dosing regimen improved target exposure achievement rate from 82.0%in traditional regimen to 93.5%(P=0.009),and reduced postoperative residual muscle relaxation incidence from 13.0%to 3.5%(P=0.018).The sarcopenia group showed the most significant improvement in achievement rate,from 71.4%to 93.8%(P=0.017).CONCLUSION SMI shows strong correlation with rocuronium distribution volume in obese colorectal cancer patients and is a key factor affecting drug distribution.SMI-based individualized dosing strategies can significantly improve target exposure achievement rate and reduce postoperative residual muscle relaxation incidence,providing scientific evidence for precision anesthesia management in obese patients.
基金funded by the National Institutes of Health(R01AR077132)AHA collaborative award(944227)supported by Marie-Curie post-doctoral fellowship awarded by European Commission(GAP-101109659)。
文摘Muscle cell-powered biohybrid robots represent a transformative fusion of biological tissue engineering and robotics,offering unprecedented potential for biomedical applications targeted at drug delivery,regenerative medicine,bioengineered heart patches,lab-on-a-chip devices,biosensors,and soft surgical tools.This review categorizes the currently available examples and further explores advanced biofabrication techniques that drive the development of biohybrid systems,with a focus on 3D bioprinting,electrospinning,micro/nano patterning,self-assembly,and microfluidic devices.These fabrication strategies facilitate precise cell alignment,enhance electrical and mechanical properties,and enable the seamless integration of biological components with engineered structures.By incorporating both cardiomyocytes and skeletal muscle cells,biohybrid robots achieve controlled actuation,autonomous movement,and adaptability to environmental stimuli.Furthermore,we discuss the latest optimization strategies in biofabrication,addressing key challenges such as scalability,biocompatibility,and functional integration.Biohybrid robots,including swimmers,actuators,and pumps,enable targeted drug delivery,assistive devices,and fluid transport in engineered tissues.Their integration with biological systems advances regenerative medicine,disease modeling,drug screening,and soft robotics.This review provides a comprehensive perspective on the state-of-the-art advancements and potential optimization in the fabrication techniques,paving the way for the next generation of biohybrid robotic systems.
基金supported by the Doctor of Excellence Program,The First Hospital of Jilin University(No.JDYY-DEP-2022024).
文摘Background:Calcium and vitamin D play crucial roles in muscle health and fat distribution.Both dietary intake and serum levels of calcium and vitamin D are commonly examined in relation to overall body health.Methods:The United Kingdom Biobank(UKB)database was searched and analyzed.Dietary and serum calcium and vitamin D levels were extracted from the data to evaluate potential associations with body composition.Linear regression analysis,ordinal regression analysis,and interaction analysis were used to examine the associations between variables.Results:In the survey of over 50,000 individuals in the UKB,the frequency of low handgrip strength was higher among those with low dietary calcium intake at baseline.Furthermore,individuals with low serum vitamin D levels exhibited a higher prevalence of high body fat percentage(BFP)events.Notably,these influences were observed to persist for nearly 10 years.Moreover,the data suggested that serum vitamin D levels should exceed 50 nmol/L and the daily dietary calcium intake should be at least 1,000 mg to maintain the strength and keep a lower BFP(OR:0.68,95%CI:0.52-0.90,P=0.0057).Conclusions:These findings underscore the importance of increasing calcium and vitamin D intake and monitoring serum vitamin D levels for effective public health strategies.
基金supported by the MUSC-TU Scholarship for Human Resource Development in Science & Technology in the Remembrance of Late King Rama Ⅸ of ThailandPartial Funding for Graduate Student Thesis for the Year 2021 by the Faculty of Graduate Studies and Graduate Studies of Mahidol University Alumni Association。
文摘Background: Post-workout supplementation has been used in athletes and recreational exercisers;however, responses between normal and overweight individuals on exercise performance and muscle recovery are less known.Methods: Normal and overweight young adult males(21 subjects/group) participated in resistance and fatiguing exercises before receiving post-workout supplements: placebo, coenzyme Q10(CoQ10), or sports drink in a crossover design. Resistance exercises included upper body exercise(bench press, upright row, and standing shoulder press) and lower body exercise(dead lift, back squat, and front squat) at 75% of one-repetition maximum(1 RM). Fatiguing exercise was performed on a cycle ergometer with 3 min of all-out effort at 3.5% of body mass. Participants consumed post-workout supplements within 10 min of exercise completion and repeated-bout exercise was performed 1 h later, followed by cardiovascular responses, urinary biomarkers, and delayed onset muscle soreness(DOMS) assessments.Results: There were effects of overweight on resistance exercise volume, critical power, fatigue index, and postexercise diastolic blood pressure(DBP). However, no differences in urinary biomarkers of muscle damage(potassium and creatinine) or DOMS between normal and overweight individuals. After supplementation, CoQ10 and sports drink increased resistance exercise volume regardless of body mass and increased critical power in the normal group. Additionally, CoQ10 supplementation was associated with a reduction in urinary biomarkers and DOMS in both groups.Conclusion: These findings are beneficial for sport scientists, nutritionists, and exercise physiologists in guiding post-workout supplementation with CoQ10 and sports drink to improve exercise performance and muscle recovery in normal and overweight individuals.
基金funded by research grants from the National Natural Science Foundation of China (32171135 and 32371168)。
文摘Purpose: This study aimed to explore the effects of a 10-week combined exercise regimen on immobilizationinduced muscle atrophy and elucidate the possible function of Protein arginine methyltransferase 1(Prmt1) in this process.Methods: 8-week-old male C57BL/6J mice were carried out combined exercise for 10 weeks. One week before the end of the intervention, mice underwent cast immobilization. Additionally, to investigate the potential mechanism in exercise-induced protection of skeletal muscle, mice in the exercise preconditioning group were administered TC-E-5003(an inhibitor of Prmt1 enzymatic activity). Exercise performance, muscle mass, and the cross-sectional area(CSA) of muscle fibers were analyzed. Besides, Prmt1 and Sestrin1(Sesn1) were either overexpressed or inhibited in C2C12 myotubes to elucidate the underlying mechanism.Results: Exercise preconditioning not only significantly improved muscle mass and motor ability in immobilized mice but also inhibited excessive activation of degradation pathways and enhanced protein synthesis. Importantly, Prmt1 mediated the protective effects of exercise preconditioning on muscle atrophy. Mechanistically,Prmt1 regulated the p38 mitogen-activated protein kinase(p38)/activating transcription factor 2(ATF2)pathway, which modulates Sesn1 expression. Sesn1 acts as a downstream of Prmt1 and ATF2, contributing to the myoblast differentiation and skeletal muscle regeneration through AMP-Activated protein kinase α2(AMPKα2)/transcriptional co-activator PPAR-γ co-activator-1 α(PGC-1α) signaling pathway.Conclusions: Taken together, our results highlighted the effectiveness of exercise preconditioning in preventing muscle atrophy via the Prmt1-Sesn1 pathway.
基金supported by the Sustainable Development Special Project from Shenzhen,China(KCXFZ20201221173213037)the National Natural Science Foundation of China(32172697 and U23A20229)+1 种基金the Guangdong Provincial Natural Science Foundation(2021A1515011336)the Agricultural Science and Technology Innovation Program,China(CAASZDRW202406)。
文摘Genetic improvement of meat production traits has always been the primary goal of pig breeding.Geographical isolation,natural and artificial selection led to significant differences in the phenotypes of meat production traits between Chinese local pigs and Western commercial pigs.Comparative genomics and transcriptomics analysis provided powerful tools to identify genetic variants and genes associated with skeletal muscle growth.However,the number of available genetic variants and genes are still limited.In this study,a comprehensive comparison of transcriptomes showed that ribosomal protein S27-like(RPS27L)gene was highly expressed in skeletal muscle and up-regulated in Chinese local pigs when compared with Western commercial pigs.Functional analysis revealed that overexpression of RPS27L promoted myoblast proliferation and repressed differentiation in pig skeletal muscle cells.Conversely,the knockdown of RPS27L led to the inhibition of myoblast proliferation and the promotion of differentiation.Notably,a 13-bp insertion-deletion(InDel)mutation was identified within the RPS27L promoter,inserted in Chinese local breeds and predominantly deleted in Western commercial breeds.Luciferase reporter assay suggested this InDel modulated RPS27L expression by influencing transcription factor 3(TCF3)and myogenic differentiation antigen(MYOD)binding to the promoter.Furthermore,a positive correlation was observed between RPS27L expression and backfat thickness.Association studies demonstrated this InDel was significantly associated with the body weight of pigs at the age of 240 d.Together,our results suggested that RPS27L was a regulator of skeletal muscle development and growth,and was a candidate marker for improving meat production traits in pigs.This study not only provided a biomarker for animal breeding,but also was helpful for understanding skeletal muscle development and muscular disease in humans.
文摘Objective:To investigate the effect of a water-soluble nacre extract derived from Pinctada fucata on skeletal muscle aging.Methods:Naturally aged C57BL/6J mice received nacre extract mixed in chow for 12 weeks.Forelimb grip strength,hanging performance,and locomotor activity were assessed.Skeletal muscle remodeling and signaling were evaluated by histology and immunostaining for fibrosis,contractile-marker features,senescence-and DNA damage-associated markers,inflammatory signaling,and mitochondrial proteins.Oxidative status was assessed by determining antioxidant capacity,lipid peroxidation,and oxidative DNA damage.Transcriptomic profiling was also performed,and selected targets were validated by quantitative RT-PCR and immunostaining.In addition,differentiated C2C12 myotubes were exposed to doxorubicin and treated with nacre extract;senescence-associated β-galactosidase,DNA damage signaling,and cell viability were measured.Results:Nacre extract increased forelimb grip strength and showed a positive trend in hanging performance without altering spontaneous locomotion.It also reduced collagen deposition,preserved contractile-marker immunoreactivity,attenuated senescence-and inflammation-associated signals,and increased mitochondrial protein immunoreactivity.Oxidative DNA damage was notably reduced by nacre extract.Transcriptomics indicated modulation of stress/redox programs and increased neurotrophic tyrosine kinase receptor type 2 expression,which were supported by tissue-level validation.In C2C12 myotubes,nacre extract suppressed doxorubicin-induced senescence-associated phenotypes without loss of cell viability.Conclusions:Water-soluble nacre extract mitigates skeletal muscle aging through coordinated modulation of oxidative stress,inflammation,mitochondrial features,and cellular senescence.
基金funded by the Project of National Key Research and Development Program of China(2022YFD2101001)the Project of National Natural Science Foundation of China(32172226)+4 种基金China Agriculture Research System(CARS-40-K25CARS-40-S11)the Special Fund for Anhui Agriculture Research System(AHCYJSTX-NCPJG)-15the Project of Key Laboratory for Animal Food Green Manufacturing and Resource Ming of Anhui Province(PA2023GDSK0125)the Cooperative Project of Hefei University of Technology-Anhui Rongda Food Co.,Ltd.(W2020JSKF0489).
文摘Skeletal muscle injuries are prone to induce fatigue,decrease resistance and imbalances in the body.Although ovalbumin(OVA)has such biological effect as promoting tissue development and immunomodulation,its impact on repairing skeletal muscle injuries has been rarely reported.In this study,a mouse model of muscle injury was constructed and found that OVA significantly increased muscle weight,muscle thickness,and exercise capacity in muscle-injured mice.Meanwhile,OVA improved the morphology of muscle tissues by reducing serum levels of urea nitrogen,creatine kinase,and lactate dehydrogenase,as well as decreasing the levels of inflammatory factors interleukin(IL)-1β,tumor necrosis factor α,and IL-6,respectively.In addition,transcriptomic and metabolomic analyses revealed that OVA could enhance muscle tissue morphology by upregulating the phosphatidylinositol 3-kinase-protein kinase B signaling pathway and improving amino acid metabolism through the upregulation of Col11a2,Ccn2,Thbs1,Tnc,Klf2,Bcl2l1,Adh3a1,and Rsad1.The study provided a theoretical foundation for understanding the molecular mechanisms in OVA-aided muscle injury repair.
基金funded by research grant from National Natural Science Foundation of China(32171135).
文摘Resistance exercise has been confirmed to be important for maintaining muscle mass and function.However,despite considerable experimental studies,the underlying mechanisms still requires further investigation to be elucidated.Sestrin1 is a stress-inducible protein strongly associated with the occurrence and development of skeletal muscle dysfunction.Besides,oxidative stress is believed to be a major pathogenic mechanism in the development of skeletal muscle atrophy,whereas regular exercise training induces the endogenous antioxidative system and protects the body against adverse effects of oxidative stress.Nevertheless,whether Sestrin1 is involved in the amelioration of resistance exercise on muscle atrophy and the role of its antioxidant function in this process remains unknown.Here we show that six-week resistance exercise training significantly improved muscle function,muscle mass,and oxidative damage and maintained the level of Sestrin1 in dexamethasone-treated C57BL/6J mice.Mechanistically,Sestrin1 overexpression rescued protein degradation and oxidative stress in atrophied myotubes.Furthermore,an emerging regulator of cellular defense against toxic and oxidative insults,nuclear factor erythroid2–related factor 2(Nrf2)controls the basal and induced expression of an array of antioxidant response element–dependent genes to regulate the pathophysiological outcomes of oxidant exposure.In this study,we found that Nrf2 is a target of Sestrin1,and Nrf2 nuclear translocation is facilitated by Sestrin1.ML385(an Nrf2 inhibitor)treatment mitigated the regulatory effects of overexpression-Sestrin1.Therefore,Sestrin1 was involved in the process of resistance exercise against skeletal muscle atrophy,which may be closely related to its antioxidant capacity,revealing a potential therapeutic strategy for reducing the loss of skeletal muscle.
基金supported by the National Natural Science Foundation of China,No.82072162(to XY).
文摘To perform various functions in the body,skeletal muscle is controlled and coordinated as a whole by nerves.However,there has been little research into whether the nerve control characteristics of different muscles are different,and the importance of these potential differences.In the present study,we used a three-dimensional imaging of solvent-cleared organ-compatible multi-tracer technique to explore the spatial distribution patterns of sensory and sympathetic neurons that innervate limb muscles.We integrated transcriptome sequencing datasets from mouse limb muscles in public databases and performed correlation analysis with neuronal spatial distribution data to reveal the unique effects of different types of neurons on muscle functional pathways.In terms of spatial distribution patterns,sympathetic neurons exhibited a more concentrated distribution than sensory and motor neurons.In addition,the neuronal innervation of limb muscles exhibited four different characteristics:sympathetic neuron-rich muscle,sensory neuron-rich muscle,neuron-sparse muscle,and motor neuron-rich muscle.Sensory neuron density was mainly associated with muscle contractile structure and cell pH,whereas sympathetic neuron density was associated with protein kinase activity,muscle vasculature,muscle calcium-dependent protein kinase activity,lipid transport,and vesicle release.Motor neuron density was mainly associated with protein kinase activity,cell adhesion,oxidoreductase activity,and exocytosis.These findings may contribute to a deeper understanding of how nerves cooperate to endow muscles with diverse physiological functions,thereby providing new insights and experimental evidence for the treatment of various neuromuscular diseases.
文摘Purpose:ATLAS is a cross-sectional study aiming to investigate environmental and genetic determinants of athletic performance in healthy Greek competitive athletes(CA).This article presents the study design,investigates the muscle strength performance(MSP)of 289 adult and teenage CA,exercisers,and physically inactive individuals(PI),and proposes predictive models of MSP for adults.Methods:Muscle maximal,speed,and explosive strength(MMS/MSS/MES)at unilateral maximal concentric flexion and extension contraction(FC/EC)were evaluated using Biodex System 3 PRO^(TM)at 60°/s,180°/s,and 300°/s,while additional performance markers were assessed through field ergometric testing.Participants were interviewed about their lifestyle,dietary habits,physical activity,injury,and medical history.Body composition was assessed via bioelectrical impedance.gDNA was extracted from biochemical samples and then genotyped.Statistical analysis was conducted using IBM SPSS Statistics v21.0 and R.Results:Age,fitness,and sex impacted correlations of MSP with body composition and anthropometric measurements(p<0.05).Among CA,females outperformed males in accuracy(p<0.001)while,males outperformed females in anaerobic power,MSP,speed,and endurance(p<0.001).Adult CA outperformed exercisers and PI in MMS,MSS,and MES(p<0.05).Multiple linear regression models,with predictors age,FFM,body extremity,training load explained the majority of variation in MMS(R^(2)_(adj):71.4%–88.9%),MSS(R^(2)_(adj):64.8%–78.4%),and MES(R^(2)_(adj):52.7%–68.4%)at EC,FC,and their mean(p<0.001).Conclusions:Muscle-strengthening strategies should be customized according to individual fitness levels,body composition,and anthropometric measurements.The innovative sex-specific regression models assessing MMS,MSS,and MES at EC and FC provide a framework for personalizing rehabilitation and skill-specific training strategies.
基金supported by Joint Program on Health Science&Technology Innovation of Hainan Province(WSJK2024QN093)Discipline Leader Development Program for Outstanding Talents of Hainan West Central Hospital.
文摘Objectives:Postmenopausal women with stress urinary incontinence(SUI)exhibit low androgen expression.This study aimed to evaluate the efficacy and safety of vaginal androgen combined with pelvic floor muscle training(PFMT)in the treatment of SUI in postmenopausal women.Methods:Postmenopausal women with SUI were recruited from Hainan West Central Hospital between January 2024 and March 2025.Participants were randomly assigned in a double-blind manner to receive either vaginal androgen cream combined with PFMT(treatment group)or a visually identical placebo cream(without androgens)combined with PFMT(control group).The vaginal cream was applied to the vaginal wall at a dose of 0.5 g per application,twice weekly for a total of 10 applications,while PFMT was conducted for 8 weeks.The clinical efficacy and safety were compared between the two groups.Results:A total of 61 patients were finally enrolled,with 31 in the treatment group and 30 in the control group.At both 3-month and 6-month follow-ups,the treatment group demonstrated significantly lower values in daily pad usage(p<0.05),24-h pad test scores(p<0.05),and ICIQ-UI SF scores(p<0.05)compared to the control group.The improvement rate of urinary incontinence was significantly higher in the treatment group(p<0.05).Compared to baseline,the treatment group showed statistically significant reductions in all three outcome measures(all p<0.05).No severe adverse events were reported in either group during the treatment period.Conclusions:Androgen therapy combined with PFMT significantly improved the urinary incontinence remission rate in postmenopausal women with SUI,with no severe adverse effects observed.These findings suggest that androgen therapy may represent a novel therapeutic approach for SUI management in postmenopausal women.
基金partly funded by National Key R&D Program of China(2023YFD1301405)the 2115 Talent Development Program of China Agricultural University。
文摘Skeletal muscle accounts for approximately 40%of body mass and 50%–75%of whole-body protein,playing a central role in meat production and quality.Efficient protein synthesis in skeletal muscle relies on an adequate supply of nutrient substrates and a balanced amino acid profile.Branched-chain amino acids(BCAA),including leucine(Leu),isoleucine(Ile),and valine(Val),are the most abundant essential amino acids in skeletal muscle and contribute to both protein synthesis and oxidative energy production.Additionally,BCAA function as signaling molecules that regulate gene expression and protein phosphorylation cascades,which significantly influence physiological processes,such as protein synthesis and degradation,glucose and lipid metabolism,and cell apoptosis and autophagy.These processes are primarily mediated through the PI3K/AKT/AMPK/mTOR signaling pathways.This review summarizes BCAA transporters and catabolic metabolism,their role as signaling molecules in regulating protein metabolism and glucose and lipid equilibrium,and applications in animal production.These findings offer both theoretical insights and practical guidelines for the precise regulation of feed efficiency and production performance through tailored dietary BCAA supplementations.
文摘Background Heat shock proteins(HSPs)are key molecular chaperones that help maintain protein homeostasis by stabilizing or removing damaged proteins during cellular stress.Aging weakens these stress–response systems,disrupting proteostasis and increasing vulnerability to sarcopenia.High-intensity training(HIT)can counteract these declines by activating protective pathways such as the HSP response.HSPs are highly responsive to stress,examining their regulation during aging is important,as altered HSP activity is linked to the progressive loss of muscle mass.Methods This study investigated the abundance and phosphorylation of HSPs in skeletal muscle from healthy,active young and older adults(n=7 per group),assessed at baseline and again in the older group following 12 weeks of HIT.Using calibrated Western blotting on both whole-muscle homogenates and pooled single muscle fibres,we quantified HSP content and phosphorylation to determine how aging and exercise influence stress–responsive protein regulation at both the tissue and cellular levels.Results In whole muscle homogenates,HSPs(HSP72,HSP27,andαB-crystallin)did not differ between young and older adults,while higher phosphorylation of small HSPs(sHSPs):phospho-HSP27 at Serine15(pHSP27 Ser15)and phospho-αB-crystallin at Serine59(pαB-crystallin Ser59)(∼1.8-fold and∼2.9-fold,respectively)were found in muscle from older adults,indicating higher cellular stress associated with aging.A 12-week HIT intervention in older adults reduced homogenate pHSP27 Ser15 and pαB-crystallin Ser59 abundances to similar levels found in young adults.Total HSPs typically displayed a distinct fiber-type profile in both age groups,with more in type I compared to type II fibers,distinguished by the presence of myosin heavy chain I(MHCI)or MHCII.Phosphorylation at pHSP27 Ser15 and pαB-crystallin Ser59 was not different between type I and type II fibers.The HIT in older adults decreased total and phosphorylated sHSPs in both type I and type II fibers but increased HSP72 in type I fibers.Conclusion HIT has the potential to mitigate age-related cellular stress and modulate protein expression patterns in aging skeletal muscle and,perhaps,has the potential to delay age-related muscle decline,thereby improving muscle health in older adults.
文摘Background Intrinsic and extrinsic foot muscles contribute to foot and lower limb function.This knowledge provides opportunities to target these muscles in exercise and rehabilitation.However,a barrier is the limited understanding of how prescribed exercises affect muscle activation and force output.This study examined muscle activation and torque production about the metatarsophalangeal joints of intrinsic and extrinsic foot muscles during common foot strengthening exercises.The secondary aim was to determine whether the addition of a postural change(leaning forward)or addition of mass can further increase muscle activation and torque.Methods Fifteen healthy participants(9 males,6 females;age=36.5±8.0 years,mean±SD)participated.Muscle activation was measured using fine-wire electromyography(EMG)electrodes for 2 intrinsic and 2 extrinsic muscles,and surface EMG electrodes for 4 superficial muscles.Metatarsophalangeal joint torque was measured using a custom toe dynamometer.Participants attended one 90-min session and performed 16 exercises.Five included the addition of leaning forward and 3 the addition of mass(20%of participant’s mass)to compare their effects on muscle activity and torque.Results Muscle activation and metatarsophalangeal joint torque varied considerably across exercises.Both the addition of leaning forward and the addition of mass increased muscle activation and metatarsophalangeal joint torque,with the addition of leaning forward producing a 35%median increase in torque about the metatarsophalangeal joints.Conclusion Many common exercises,despite high muscle activation,produce relatively low metatarsophalangeal joint torque,raising questions about their clinical value.Adding a forward lean significantly increases toe flexor muscle activity and torque,reaching levels greater than added mass and comparable to walking.
文摘Amyotrophic lateral sclerosis(ALS)is a progressive neurodegenerative disease marked by motor neuron(MN)degeneration,neuromuscular junction disruption,and muscle atrophy,ultimately leading to paralysis and death.Despite extensive research,no effective treatment exists,highlighting the need to elucidate mechanisms driving ALS pathogenesis.About 90%of ALS cases are sporadic ALS and lack a clear genetic cause;the remaining 10%are familial ALS,associated with mutations in over 25 genes.The most common mutations are in superoxide dismutase 1(SOD1)and C9ORF72,with rarer variants in FUS,TARDBP,TBK1,and VCP.
