<strong>Introduction: </strong>Hydatid cyst formation is rare in organs such as muscle, bone and spine. Para-spinal involvement is an uncommon finding with a prevalence of less than 0.5% in the literatures...<strong>Introduction: </strong>Hydatid cyst formation is rare in organs such as muscle, bone and spine. Para-spinal involvement is an uncommon finding with a prevalence of less than 0.5% in the literatures. <strong>Presentation of Case: </strong>In the present paper, we reported a case of primary hydatid cyst in lumbar para-spinal area. The patient presented with complaint of chronic back pain and swelling in right thoracolumbar area. A suspicious mass was revealed in lumbar spine x-ray presenting as multi-loculated cystic mass on further evaluation by magnetic resonance imaging (MRI). The patient underwent surgery and the cyst was excised completely. Histopathological evaluations confirmed the hydatid disease. <strong>Discussion:</strong> Hydatid disease is a zoonotic infectious disease caused by <em>Echinococcus granulosus</em>. The parasitic cysts can form in any part of the host body. The liver and lungs are the most commonly involved organs. The occurrence of these lesions in certain areas such as para-spinal muscles is rare. The cystic mass is detected by radiologic modalities and is confirmed by pathologic examination. Surgery is the mainstay of treatment. <strong>Conclusion:</strong> Hydatid disease should be on differential diagnosis list facing a cystic lesion in any part of the body especially in the endemic areas. Moreover, radiologic and serologic assessments are important in confirming the diagnosis.展开更多
Background N^(6)-methyladenosine(m^(6)A)methylation is a key epigenetic modification that can modulate gene expression and strongly affect mammalian developmental processes.However,the genome-wide methylation of long ...Background N^(6)-methyladenosine(m^(6)A)methylation is a key epigenetic modification that can modulate gene expression and strongly affect mammalian developmental processes.However,the genome-wide methylation of long non-coding RNAs(lncRNAs)and its implications for the development of skeletal muscle remain poorly understood.Bovine skeletal muscle samples from five developmental stages were analyzed in this study to establish lncRNA methylome and transcriptomic maps.Results Globally,59.67%of lncRNAs in skeletal muscle with m^(6)A modifications,and this percentage decreased progressively during development.lncRNA expression levels were positively associated with the number of m^(6)A peaks,with lncRNAs possessing 3 or more peaks showing significantly higher expression levels than those with 1 or 2 peaks.Specific lncRNAs involved in skeletal muscle development were identified through two analytical approaches.The first approach employed weighted gene co-expression network analysis(WGCNA)of transcriptomic data to identify correlations between annotated lncRNAs and growth-related traits,resulting in 21 candidate hub lncRNAs.The intersection of these 21 hub lncRNAs with 151 differentially methylated lncRNAs(DM-lncRNAs)identified 10 shared candidate lncRNAs.The second approach integrated MeRIP-seq and RNA-seq data to identify 36 lncRNAs that were both differentially m^(6)A modified and differentially expressed(dme-lncRNAs).GO and KEGG enrichment analyses of cis-target genes associated with these dme-lncRNAs identified eight candidate lncRNAs.Combining the results from the two approaches identified 16 key m^(6)A-modified lncRNAs likely involved in skeletal muscle development.Conclusions These findings highlight the regulatory and functional significance of dynamic lncRNA methylation in skeletal muscle development.展开更多
This paper endeavours to bridge the existing gap in muscular actuator design for ligament-skeletal-inspired robots,thereby fostering the evolution of these robotic systems.We introduce two novel compliant actuators,na...This paper endeavours to bridge the existing gap in muscular actuator design for ligament-skeletal-inspired robots,thereby fostering the evolution of these robotic systems.We introduce two novel compliant actuators,namely the Internal Torsion Spring Compliant Actuator(ICA)and the External Spring Compliant Actuator(ECA),and present a comparative analysis against the previously conceived Magnet Integrated Soft Actuator(MISA)through computational and experimental results.These actuators,employing a motor-tendon system,emulate biological muscle-like forms,enhancing artificial muscle technology.Then,applications of the proposed actuators in a robotic arm inspired by the human musculoskeletal system are presented.Experiments demonstrate satisfactory power in tasks like lifting dumbbells(peak power:36 W),playing table tennis(end-effector speed:3.2 m/s),and door opening,without compromising biomimetic aesthetics.Compared to other linear stiffness serial elastic actuators(SEAs),ECA and ICA exhibit high power-to-volume(361×10^(3)W/m^(3))and power-to-mass(111.6 W/kg)ratios respectively,endorsing the biomimetic design’s promise in robotic development.展开更多
The muscular system plays a critical role in the human body by governing skeletal movement,cardiovascular function,and the activities of digestive organs.Additionally,muscle tissues serve an endocrine function by secr...The muscular system plays a critical role in the human body by governing skeletal movement,cardiovascular function,and the activities of digestive organs.Additionally,muscle tissues serve an endocrine function by secreting myogenic cytokines,thereby regulating metabolism throughout the entire body.Maintaining muscle function requires iron homeostasis.Recent studies suggest that disruptions in iron metabolism and ferroptosis,a form of iron-dependent cell death,are essential contributors to the progression of a wide range of muscle diseases and disorders,including sarcopenia,cardiomyopathy,and amyotrophic lateral sclerosis.Thus,a comprehensive overview of the mechanisms regulating iron metabolism and ferroptosis in these conditions is crucial for identifying potential therapeutic targets and developing new strategies for disease treatment and/or prevention.This review aims to summarize recent advances in understanding the molecular mechanisms underlying ferroptosis in the context of muscle injury,as well as associated muscle diseases and disorders.Moreover,we discuss potential targets within the ferroptosis pathway and possible strategies for managing muscle disorders.Finally,we shed new light on current limitations and future prospects for therapeutic interventions targeting ferroptosis.展开更多
BACKGROUND Skeletal muscle alterations(SMAs)are being increasingly recognized in patients with metabolic dysfunctionassociated steatotic liver disease(MASLD)and appear to be associated with deleterious outcomes in the...BACKGROUND Skeletal muscle alterations(SMAs)are being increasingly recognized in patients with metabolic dysfunctionassociated steatotic liver disease(MASLD)and appear to be associated with deleterious outcomes in these patients.However,their actual prevalence and pathophysiology remain to be elucidated.AIM To determine the prevalence of SMAs and to assess the significance of circulating myokines as biomarkers in patients with MASLD.METHODS Skeletal muscle strength and muscle mass were measured in a cross-sectional study in a cohort of 62 patients fulfilling MASLD criteria,recruited from the outpatient clinics of a tertiary level hospital.The degree of fibrosis and liver steatosis was studied using abdominal ultrasound and transitional elastography.Anthropometric and metabolic characteristics as well as serum levels of different myokines were also determined in the MASLD cohort.Statistical analysis was performed comparing results according to liver fibrosis and steatosis.RESULTS No significant differences were found in both skeletal muscle strength and skeletal muscle mass in patients with MASLD between different stages of liver fibrosis.Interestingly,serum levels of fibroblast growth factor-21(FGF21)were significantly higher in patients with MASLD with advanced hepatic fibrosis(F3-F4)than in those with lower fibrosis stages(F0-F2)(197.49±198.27 pg/mL vs 95.62±83.67 pg/mL;P=0.049).In addition,patients with MASLD with severe hepatosteatosis(S3)exhibited significantly higher serum levels of irisin(1116.87±1161.86 pg/mL)than those with lower grades(S1-S2)(385.21±375.98 pg/mL;P=0.001).CONCLUSION SMAs were uncommon in the patients with MASLD studied.Higher serum levels of irisin and FGF21 were detected in patients with advanced liver steatosis and fibrosis,respectively,with potential implications as biomarkers.展开更多
BACKGROUND Pain in the back or pelvis or fear of back pain may affect the timing or cocontraction of the core muscles.In both static and dynamic movements,the Sahrmann core stability test provides an assessment of cor...BACKGROUND Pain in the back or pelvis or fear of back pain may affect the timing or cocontraction of the core muscles.In both static and dynamic movements,the Sahrmann core stability test provides an assessment of core muscle activation and a person's ability to stabilize the lumbopelvic complex.Preparatory cues and images can be used to increase the activation of these muscles.To attain optimal movement patterns,it will be necessary to determine what cueing will give the most effective results for core stability.AIM To investigate the effects of external and internal cues on core muscle activation during the Sahrmann five-level core stability test.METHODS Total 68 participants(21.83±3.47 years)were randomly allocated to an external(n=35)or internal cue group(n=33).Participants performed the Sahrmann fivelevel core stability test without a cue as baseline and the five-level stability exercises with an internal or external cue.External cue group received a pressure biofeedback unit(PBU),and the internal cue group received an audio cue.A Delsys Trigno^(TM)surface electromyography unit was used for muscle activation from the rectus abdominis,external oblique,and transverse abdominis/internal oblique muscles.RESULTS Linear mixed effects model analysis showed that cueing had a significant effect on core muscle activation(P=0.001);however,there was no significant difference between cue types(internal or external)(P=0.130).CONCLUSION Both external and internal cueing have significant effects on core muscle activation during the Sahrmann five-level core stability test and the PBU does not create higher muscle activation than internal cueing.展开更多
Background: Aging-induced cardiac hypertrophy and reduced skeletal muscle strength contribute to increased disease risk and life burden in the elderly. FNDC5 acts as a protective muscle factor in both cardiac and skel...Background: Aging-induced cardiac hypertrophy and reduced skeletal muscle strength contribute to increased disease risk and life burden in the elderly. FNDC5 acts as a protective muscle factor in both cardiac and skeletal muscle. This study aims to examine the relationship between cardiac FNDC5 and aging-related cardiac hypertrophy and decreased skeletal muscle strength. Methods: Male young C57BL/6 mice (5 months old, n = 6) and aged mice (21 months old, n = 6) were utilized in the study and housed in a specific pathogen-free (SPF) environment. Prior to the experiment, grip strength tests were performed on the mice, and heart tissues were collected for morphological analysis, including the assessment of peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) and fibronectin type III-containing structural domain 5 (FNDC5) protein levels. Furthermore, myosin heavy chain II (MyHC II), skeletal muscle-specific transcription factor (MyoD), muscle RING-finger protein-1 (MuRF1), and FNDC5 levels were evaluated in the quadriceps muscle. The correlations between heart weight and FNDC5 expression levels, as well as skeletal muscle indices in the mice, were subsequently analyzed. Result: Aging leads to cardiac hypertrophy and reduced expression of PGC-1α and FNDC5 proteins. Concurrently, there is a decline in the strength of skeletal muscle, along with decreased expression of MyHC II and increased expression of MURF1 and MyoD. Correlation analysis demonstrated strong positive associations between myocardial FNDC5 protein levels and limb grip strength, as well as MyHC II, and strong negative associations with MyoD and MuRF1. Conclusion: There may be a significant association between aging-induced cardiac hypertrophy and decreased skeletal muscle strength, with FNDC5 potentially playing a crucial role as a regulatory molecule facilitating communication between the heart and skeletal muscle.展开更多
The“longevity protein”SIRT5 could hold the key to delaying age-related muscle decline.A study led by researchers from the Institute of Zoology(IOZ)of the Chinese Academy of Sciences and Capital Medical University in...The“longevity protein”SIRT5 could hold the key to delaying age-related muscle decline.A study led by researchers from the Institute of Zoology(IOZ)of the Chinese Academy of Sciences and Capital Medical University in Beijing reveals that SIRT5 mitigates skeletal muscle aging by blocking pro-inflammatory pathways.Published in Nature Metabolism on March 14,2025,the work identifies SIRT5’s interaction with protein kinase TBK1 as critical to preserving muscle mass and function.展开更多
Systematic bone and muscle loss is a complex metabolic disease,which is frequently linked to gut dysfunction,yet its etiology and treatment remain elusive.While probiotics show promise in managing diseases through mic...Systematic bone and muscle loss is a complex metabolic disease,which is frequently linked to gut dysfunction,yet its etiology and treatment remain elusive.While probiotics show promise in managing diseases through microbiome modulation,their therapeutic impact on gut dysfunction-induced bone and muscle loss remains to be elucidated.Employing dextran sulfate sodium(DSS)-induced gut dysfunction model and wide-spectrum antibiotics(ABX)-treated mice model,our study revealed that gut dysfunction instigates muscle and bone loss,accompanied by microbial imbalances.Importantly,Bifidobacterium animalis subsp.lactis A6(B.lactis A6)administration significantly ameliorated muscle and bone loss by modulating gut microbiota composition and enhancing butyrate-producing bacteria.This intervention effectively restored depleted butyrate levels in serum,muscle,and bone tissues caused by gut dysfunction.Furthermore,butyrate supplementation mitigated musculoskeletal loss by repairing the damaged intestinal barrier and enriching beneficial butyrate-producing bacteria.Importantly,butyrate inhibited the NF-κB pathway activation,and reduced the secretion of corresponding inflammatory factors in T cells.Our study highlights the critical role of dysbiosis in gut dysfunction-induced musculoskeletal loss and underscores the therapeutic potential of B.lactis A6.These discoveries offer new microbiome directions for translational and clinical research,providing promising strategies for preventing and managing musculoskeletal diseases.展开更多
Sarcomerogenesis,the addition of serial sarcomeres in skeletal muscle myofibrils and fibres,is a natural occurrence during growth and maturation of animals,including humans.However,the detailed mechanisms that allow f...Sarcomerogenesis,the addition of serial sarcomeres in skeletal muscle myofibrils and fibres,is a natural occurrence during growth and maturation of animals,including humans.However,the detailed mechanisms that allow for sarcomerogenesis are not fully understood.In some diseases,such as cerebral palsy in children,sarcomerogenesis appears to be inhibited or at least reduced,1,2 often causing severe restrictions in muscle and joint function.展开更多
Objective:To evaluate the efficacy and safety of transcutaneous electrical acupoint stimulation(TEAS)for muscle atrophy in patients with immobilization after surgical fixation of foot and ankle fractures.Methods:This ...Objective:To evaluate the efficacy and safety of transcutaneous electrical acupoint stimulation(TEAS)for muscle atrophy in patients with immobilization after surgical fixation of foot and ankle fractures.Methods:This was a two-arm randomized controlled trial wherein 80 patients were recruited and divided into control(n=40)and intervention(n=40)groups.The control group received conventional orthopedic treatment,whereas the intervention group received TEAS and conventional treatment.The intervention group received TEAS 3 times a week for 30 min each time for 8 weeks.The primary out-comes were muscle thickness(MT)and cross-sectional area(CSA)of the rectus femoris and gastroc-nemius muscles,whereas the secondary outcome measure was echo intensity(EI).Data were collected before the fixation operations(baseline assessment)and 4 and 8 weeks after intervention.Results:Compared with baseline,the MT and CSA were reduced in both groups by the end of treatment,whereas EI increased in both groups.At week 4,the reduction in the rectus femoris CSA in the inter-vention group was significantly lower than that in the control group(P=0.02);however,the between-group differences in the MT and EI(all P>0.05)were not significant.No serious adverse events were observed in either group.Conclusion:Our study showed that TEAS can improve muscle atrophy by attenuating the decline in the muscle CSA.Because this was only a pilot trial,subsequent studies will need longer follow-ups and larger sample sizes.展开更多
Background:While muscle contractility increases with muscle temperature,there is no consensus on the best warm-up protocol to use before resistance training or sports exercise due to the range of possible warm-up and ...Background:While muscle contractility increases with muscle temperature,there is no consensus on the best warm-up protocol to use before resistance training or sports exercise due to the range of possible warm-up and testing combinations available.Therefore,the objective of the current study was to determine the effects of different warm-up types(active,exercise-based vs.passive)on muscle function tested using different activation methods(voluntary vs.evoked)and performance test criteria(maximum force vs.rate-dependent contractile properties),with consideration of warm-up task specificity(specific vs.non-specific),temperature measurement method(muscle vs.skin),baseline temperatures,and subject-specific variables(training status and sex).Methods:A systematic search was conducted in PubMed/MEDLINE,Scopus,Web of Science,Cochrane,Embase,and ProQuest.Random-effects meta-analyses and meta-regressions were used to compute the effect sizes(ES)and 95%confidence intervals(95%CIs)to examine the effects of warm-up type,activation method,performance criterion,subject characteristics,and study design on temperature-related performance enhancement.Results:The search yielded 1272 articles,of which 33 met the inclusion criteria(n=921).Increasing temperature positively affected both voluntary(3.7%/℃±1.8%/℃(mean±SD),ES=0.28(95%CI:0.14 to 0.41))and evoked(3.2%/℃±1.5%/℃(mean±SD),ES=0.65(95%CI:0.29 to 1.00))rate-dependent contractile properties(dynamic,fast-velocity force production,and rate of force development(RFD))but not maximum force production(voluntary:-0.2%/℃±0.9%/℃(mean±SD),ES=0.08(95%CI:-0.05 to 0.22);evoked:-0.1%/℃±0.8%/℃(mean±SD),ES=-0.20(95%CI:-0.50 to 0.10)).Active warm-up did not induce greater enhancements in rate-dependent contractile properties(p=0.284),maximum force production(p=0.723),or overall function(pooled,p=0.093)than passive warm-up.Meta-regressions did not reveal a significant effect of study design,temperature measurement method,warm-up task specificity,training status,or sex on the effect of increasing temperature(p>0.05).Conclusion:Increasing muscle temperature significantly enhances rate-dependent contractile function(RFD and muscle power)but not maximum force in both evoked and voluntary contractions.In contrast to expectation,no effects of warm-up modality(active vs.passive)or temperature measurement method(muscle vs.skin)were detected,although insufficient data prevented robust sub-group analyses.展开更多
1.Background When searching for the term“muscle power”on Google Scholar,about 3.7 million hits come up in 60 ms,and for the past 3 years,there were approximately 225 yearly peer-reviewed publications dealing with mu...1.Background When searching for the term“muscle power”on Google Scholar,about 3.7 million hits come up in 60 ms,and for the past 3 years,there were approximately 225 yearly peer-reviewed publications dealing with muscle power.Muscle power has been used to assess and predict athletic performance,to determine muscle rehabilitation following injury or disease,to measure functional decline as occurs in aging,and many other topics.展开更多
It is a pleasure to contribute a commentary on the very interesting review by Dr.Orcioli-Silva and colleagues1 on the simultaneous measurements of cerebral cortex and muscle tissue oxygenation during exercise in healt...It is a pleasure to contribute a commentary on the very interesting review by Dr.Orcioli-Silva and colleagues1 on the simultaneous measurements of cerebral cortex and muscle tissue oxygenation during exercise in healthy adults using near-infrared spectroscopy(NIRS).The first NIRS measurements of the cerebral cortex and muscle were performed on humans in 19772 and 1982,3 respectively.展开更多
Skeletal muscle dysfunction is a common extrapulmonary comorbidity of chronic obstructive pulmonary disease(COPD) and is associated with decreased quality-of-life and survival in patients. The autophagy lysosome pathw...Skeletal muscle dysfunction is a common extrapulmonary comorbidity of chronic obstructive pulmonary disease(COPD) and is associated with decreased quality-of-life and survival in patients. The autophagy lysosome pathway is one of the proteolytic systems that significantly affect skeletal muscle structure and function. Intriguingly, both promoting and inhibiting autophagy have been observed to improve COPD skeletal muscle dysfunction, yet the mechanism is unclear. This paper first reviewed the effects of macroautophagy and mitophagy on the structure and function of skeletal muscle in COPD, and then explored the mechanism of autophagy mediating the dysfunction of skeletal muscle in COPD. The results showed that macroautophagy-and mitophagy-related proteins were significantly increased in COPD skeletal muscle. Promoting macroautophagy in COPD improves myogenesis and replication capacity of muscle satellite cells, while inhibiting macroautophagy in COPD myotubes increases their diameters. Mitophagy helps to maintain mitochondrial homeostasis by removing impaired mitochondria in COPD. Autophagy is a promising target for improving COPD skeletal muscle dysfunction, and further research should be conducted to elucidate the specific mechanisms by which autophagy mediates COPD skeletal muscle dysfunction, with the aim of enhancing our understanding in this field.展开更多
BACKGROUND Poor musculoskeletal recovery following foot and ankle injury can result in chronic instability and persistent muscle weakness.Preliminary evidence has shown that blood flow restriction(BFR)rehabilitation c...BACKGROUND Poor musculoskeletal recovery following foot and ankle injury can result in chronic instability and persistent muscle weakness.Preliminary evidence has shown that blood flow restriction(BFR)rehabilitation can increase muscle strength and stability,helping to restore physical function and prevent repeated injury.AIM To determine whether BFR is more effective than traditional rehabilitation in improving muscle strength,size,and stability after foot and ankle injury.METHODS A systematic review and meta-analysis were performed.Articles were retrieved from MEDLINE,EMBASE,and CENTRAL databases.Included studies compared the effectiveness of BFR rehabilitation to traditional foot and ankle rehabilitation exercises.Eligible patients were those with a history of foot or ankle injury.Muscle strength,size,and dynamic balance were assessed by comparing impro vements in peak torque,cross-sectional area,and percent muscle activation.Methodological quality assessments were performed using the PEDro scale and Methodological Index for Non-Randomized Studies(MINORS).RESULTS Ten studies met the inclusion criteria.Five studies were of good to excellent quality according to the PEDro scale,and 5 studies were of moderate quality as per the MINORS criteria.Two studies compared the effect of BFR and non-BFR rehabilitation on muscle strength;the overall mean difference between the BRF and non-BFR groups was 0.09[95%CI:(0.05,0.12),P<0.0001].Two studies analyzed muscle activation following BFR and non-BFR rehabilitation;the overall mean difference between the BRF and non-BFR groups was 0.09[95%CI:(0.05,0.12),P<0.0001].Data on dynamic balance was synthesized from two studies;the mean difference between the BFR and control groups was 1.23[95%CI:(-1.55,4.01);P=0.39].CONCLUSION BFR rehabilitation is more effective than non-BFR rehabilitation at improving muscle strength and activation following foot and ankle injury.Additional studies are needed to develop a standardized BFR training protocol.展开更多
Background While maternal proline(Pro)supplementation has demonstrated efficacy in enhancing placental angiogenesis and farrowing efficiency in swine,its regulatory role in fetal skeletal muscle ontogeny remains undef...Background While maternal proline(Pro)supplementation has demonstrated efficacy in enhancing placental angiogenesis and farrowing efficiency in swine,its regulatory role in fetal skeletal muscle ontogeny remains undefined.This study systematically evaluated the temporal-specific impacts of dietary Pro supplementation during critical phases of fetal myogenesis(encompassing primary myofiber formation and secondary myofiber hyperplasia)on offspring muscle development.A total of 120 sows with similar farrowing schedules were assigned to three groups:CON(basal diet),ST-Pro(0.5%Pro supplementation during secondary myofiber formation period,from d 60 gestation to farrowing),LT-Pro(0.5%Pro supplementation spanning primary and secondary myofiber formation period:from d 20 gestation to farrowing).Results LT-Pro group significantly increased the longissimus dorsi(LD)muscle mass per unit body weight in newborn piglets compared to CON group(P<0.05),while no such effect was observed in the ST-Pro group.Metabolomic profiling revealed elevated Pro,lysine,and tryptophan levels in the LD muscle of LT-Pro group piglets,accompanied by reduced branched-chain amino acids(BCAAs;leucine,isoleucine,and valine)in both serum and muscle(P<0.05).Histological analysis demonstrated a 45.74%increase in myofiber cross-sectional area in the LT-Pro group(P<0.05).At the molecular level,LT-Pro group piglets exhibited upregulated mRNA expression levels of myogenic regulatory genes(MYOD1,MYF6)and the cell cycle accelerator CCND1(P<0.05),coupled with activation of the STAT3 signaling pathway(phosphorylated STAT3 protein increased by 2.53-fold,P<0.01).Furthermore,Pro supplementation enhanced oxidative metabolism,evidenced by elevated mitochondrial biogenesis markers(the mRNA expression levels of PPARGC1A,OPA1,and SQSTM1)and a 61.58%increase in succinate dehydrogenase activity(P<0.05).Notably,LT-Pro group piglets showed a selective shift toward slow-twitch oxidative fibers,with both MyHC1 mRNA and protein expression levels significantly upregulated(P<0.05),while the mRNA expression levels of MyHCIIb showed no significant change.Conclusions This study identified the primary fiber formation period as a critical window.Supplementation with Pro during G20–114 reprogrammed offspring skeletal muscle development through STAT3-CCND1-mediated myoblast proliferation,enhanced mitochondrial bioenergetics,and oxidative fiber specification.However,no such effects were observed during G60–114.These findings propose maternal Pro intervention as a novel strategy to enhance muscle yield and metabolic efficiency in swine production,with potential applications for improving meat quality traits linked to oxidative muscle phenotypes.展开更多
The maximal force a muscle can exert depends on its length,which has been explained by the sliding filament theory on the sarcomere level.1 A longer muscle can act over a greater range of motion and has more sarcomere...The maximal force a muscle can exert depends on its length,which has been explained by the sliding filament theory on the sarcomere level.1 A longer muscle can act over a greater range of motion and has more sarcomeres in series,which increases its capacity to produce force at a specific muscle contraction velocity because each sarcomere contracts at a lower velocity.展开更多
Pneumatic artificial muscles(PAMs)can generate multimodal movements,e.g.,linear contraction/extension,spiral torsion,and bending motions.Among these motions,contraction and extension movements can be achieved using li...Pneumatic artificial muscles(PAMs)can generate multimodal movements,e.g.,linear contraction/extension,spiral torsion,and bending motions.Among these motions,contraction and extension movements can be achieved using linear PAMs(LPAMs)designed to mimic human skeletal muscle.LPAMs have considerable potential for wearable applications and can be integrated into soft wearable robotic systems.Due to their inherent compliance,excellent human-robot interaction,safety,and low cost,LPAMs are considered potential alternatives as actuator components in the construction of wearable robots.This review presents a comprehensive overview of the bio-inspired design of LPAMs and their wearable applications.The biomechanics of human skeletal muscle,including anatomy,morphology,and biomechanical characterization,is analyzed to provide design inspirations for LPAMs and determine the assistance requirements of LPAM-based wearable robots.Herein,LPAMs are classified into four categories based on their structural shapes,including cylindrical-shaped muscles,flat-shaped muscles,fold-shaped muscles,and muscles with other shapes.In addition,this review provides an overview of the diverse physical interfaces utilized in wearable robots and presents a comparative analysis of the actuation characteristics of LPAMs and the assistance performance of LPAM-based wearable robots.This analysis was conducted in consideration of several key metrics,including the contraction ratio,maximum force,specific force,response frequency,assistive torque/bodyweight,and net metabolic cost.Finally,this review summarizes the ongoing challenges and future research directions.展开更多
Muscle strength training can effectively reduce muscle atrophy,activate muscle tissue and promote muscle strength recovery and growth.Based on our previous research,we developed four muscle strength training strategie...Muscle strength training can effectively reduce muscle atrophy,activate muscle tissue and promote muscle strength recovery and growth.Based on our previous research,we developed four muscle strength training strategies by further imitating the clinical muscle strength training methods,namely,Isokinetic centriPetal-centriPetal Exercise(IPPE),Isokinetic centriPetal-centriFuge exercise(IPFE),Isokinetic centriFuge-centriPetal Exercise(IFPE)and Isokinetic centriFuge-centriFuge Exercise(IFFE).To quantitatively evaluate the performance of the developed strategies,experiments were carried out with elbow and knee joints as examples,and muscle Endurance Ratio(ER),Flexion and Extension torque ratio(F/E)and the degree of muscle activation were extracted and calculated based on angle/torque and Surface ElectroMyoGraphy(sEMG)signals.Experimental results showed that the ER value of IFFE was significantly reduced compared with IPPE,while the F/E value of IFPE was significantly increased;this suggests that muscle centrifugation corresponds to higher training intensity;In addition,flexor and extensor muscle groups showed different levels of muscle activation in different training strategies.The results reveal that combining different muscle movement characteristics,isokinetic exercise can exert special muscle strength training effects.The study can lay the foundation for exploring subject-specific adaptive muscle strength training strategies to better adapt to different levels of muscle strength.展开更多
文摘<strong>Introduction: </strong>Hydatid cyst formation is rare in organs such as muscle, bone and spine. Para-spinal involvement is an uncommon finding with a prevalence of less than 0.5% in the literatures. <strong>Presentation of Case: </strong>In the present paper, we reported a case of primary hydatid cyst in lumbar para-spinal area. The patient presented with complaint of chronic back pain and swelling in right thoracolumbar area. A suspicious mass was revealed in lumbar spine x-ray presenting as multi-loculated cystic mass on further evaluation by magnetic resonance imaging (MRI). The patient underwent surgery and the cyst was excised completely. Histopathological evaluations confirmed the hydatid disease. <strong>Discussion:</strong> Hydatid disease is a zoonotic infectious disease caused by <em>Echinococcus granulosus</em>. The parasitic cysts can form in any part of the host body. The liver and lungs are the most commonly involved organs. The occurrence of these lesions in certain areas such as para-spinal muscles is rare. The cystic mass is detected by radiologic modalities and is confirmed by pathologic examination. Surgery is the mainstay of treatment. <strong>Conclusion:</strong> Hydatid disease should be on differential diagnosis list facing a cystic lesion in any part of the body especially in the endemic areas. Moreover, radiologic and serologic assessments are important in confirming the diagnosis.
基金supported by the National Key R&D Program of China(2023YFD1300103)the Science and Technology Plan Project of Yantai City(2023ZDCX024)+5 种基金the National Natural Science Foundation of China(32372852)the Science Fund for Distinguished Young Scholars of Shaanxi Province(2024JC-JCQN-30)Shaanxi Provincial Innovation Leadership Program in Sciences and Technologies for Young and Middle-aged Scientists(2023SR205)the China Agriculture Research System-beef(CARS-37)the Innovation Team of Cattle Industry in Technological System of Shandong Modern Agriculture Industry(SDAIT-09-03)the Key Research and Development Project in Shandong Province(Competitive Innovation Platform)(2022CXPT010).
文摘Background N^(6)-methyladenosine(m^(6)A)methylation is a key epigenetic modification that can modulate gene expression and strongly affect mammalian developmental processes.However,the genome-wide methylation of long non-coding RNAs(lncRNAs)and its implications for the development of skeletal muscle remain poorly understood.Bovine skeletal muscle samples from five developmental stages were analyzed in this study to establish lncRNA methylome and transcriptomic maps.Results Globally,59.67%of lncRNAs in skeletal muscle with m^(6)A modifications,and this percentage decreased progressively during development.lncRNA expression levels were positively associated with the number of m^(6)A peaks,with lncRNAs possessing 3 or more peaks showing significantly higher expression levels than those with 1 or 2 peaks.Specific lncRNAs involved in skeletal muscle development were identified through two analytical approaches.The first approach employed weighted gene co-expression network analysis(WGCNA)of transcriptomic data to identify correlations between annotated lncRNAs and growth-related traits,resulting in 21 candidate hub lncRNAs.The intersection of these 21 hub lncRNAs with 151 differentially methylated lncRNAs(DM-lncRNAs)identified 10 shared candidate lncRNAs.The second approach integrated MeRIP-seq and RNA-seq data to identify 36 lncRNAs that were both differentially m^(6)A modified and differentially expressed(dme-lncRNAs).GO and KEGG enrichment analyses of cis-target genes associated with these dme-lncRNAs identified eight candidate lncRNAs.Combining the results from the two approaches identified 16 key m^(6)A-modified lncRNAs likely involved in skeletal muscle development.Conclusions These findings highlight the regulatory and functional significance of dynamic lncRNA methylation in skeletal muscle development.
基金research project funded by the National Natural Science Foundation of China(NSFC)under Grant 91948302 and Grant 52021003Research England fund at NERIC.
文摘This paper endeavours to bridge the existing gap in muscular actuator design for ligament-skeletal-inspired robots,thereby fostering the evolution of these robotic systems.We introduce two novel compliant actuators,namely the Internal Torsion Spring Compliant Actuator(ICA)and the External Spring Compliant Actuator(ECA),and present a comparative analysis against the previously conceived Magnet Integrated Soft Actuator(MISA)through computational and experimental results.These actuators,employing a motor-tendon system,emulate biological muscle-like forms,enhancing artificial muscle technology.Then,applications of the proposed actuators in a robotic arm inspired by the human musculoskeletal system are presented.Experiments demonstrate satisfactory power in tasks like lifting dumbbells(peak power:36 W),playing table tennis(end-effector speed:3.2 m/s),and door opening,without compromising biomimetic aesthetics.Compared to other linear stiffness serial elastic actuators(SEAs),ECA and ICA exhibit high power-to-volume(361×10^(3)W/m^(3))and power-to-mass(111.6 W/kg)ratios respectively,endorsing the biomimetic design’s promise in robotic development.
基金the National Natural Science Foundation of China(82471593 to J.M.32330047 and 31930057 to F.W.+2 种基金and 82071970 to Y.W.and 82072506 to Y.L.)the Science Fund for Distinguished Young Scholars of Hubei Province(2023AFA109 to Y.W.)Hubei Provincial Natural Science Foundation of China(2024AFB963 to Q.R.).
文摘The muscular system plays a critical role in the human body by governing skeletal movement,cardiovascular function,and the activities of digestive organs.Additionally,muscle tissues serve an endocrine function by secreting myogenic cytokines,thereby regulating metabolism throughout the entire body.Maintaining muscle function requires iron homeostasis.Recent studies suggest that disruptions in iron metabolism and ferroptosis,a form of iron-dependent cell death,are essential contributors to the progression of a wide range of muscle diseases and disorders,including sarcopenia,cardiomyopathy,and amyotrophic lateral sclerosis.Thus,a comprehensive overview of the mechanisms regulating iron metabolism and ferroptosis in these conditions is crucial for identifying potential therapeutic targets and developing new strategies for disease treatment and/or prevention.This review aims to summarize recent advances in understanding the molecular mechanisms underlying ferroptosis in the context of muscle injury,as well as associated muscle diseases and disorders.Moreover,we discuss potential targets within the ferroptosis pathway and possible strategies for managing muscle disorders.Finally,we shed new light on current limitations and future prospects for therapeutic interventions targeting ferroptosis.
文摘BACKGROUND Skeletal muscle alterations(SMAs)are being increasingly recognized in patients with metabolic dysfunctionassociated steatotic liver disease(MASLD)and appear to be associated with deleterious outcomes in these patients.However,their actual prevalence and pathophysiology remain to be elucidated.AIM To determine the prevalence of SMAs and to assess the significance of circulating myokines as biomarkers in patients with MASLD.METHODS Skeletal muscle strength and muscle mass were measured in a cross-sectional study in a cohort of 62 patients fulfilling MASLD criteria,recruited from the outpatient clinics of a tertiary level hospital.The degree of fibrosis and liver steatosis was studied using abdominal ultrasound and transitional elastography.Anthropometric and metabolic characteristics as well as serum levels of different myokines were also determined in the MASLD cohort.Statistical analysis was performed comparing results according to liver fibrosis and steatosis.RESULTS No significant differences were found in both skeletal muscle strength and skeletal muscle mass in patients with MASLD between different stages of liver fibrosis.Interestingly,serum levels of fibroblast growth factor-21(FGF21)were significantly higher in patients with MASLD with advanced hepatic fibrosis(F3-F4)than in those with lower fibrosis stages(F0-F2)(197.49±198.27 pg/mL vs 95.62±83.67 pg/mL;P=0.049).In addition,patients with MASLD with severe hepatosteatosis(S3)exhibited significantly higher serum levels of irisin(1116.87±1161.86 pg/mL)than those with lower grades(S1-S2)(385.21±375.98 pg/mL;P=0.001).CONCLUSION SMAs were uncommon in the patients with MASLD studied.Higher serum levels of irisin and FGF21 were detected in patients with advanced liver steatosis and fibrosis,respectively,with potential implications as biomarkers.
文摘BACKGROUND Pain in the back or pelvis or fear of back pain may affect the timing or cocontraction of the core muscles.In both static and dynamic movements,the Sahrmann core stability test provides an assessment of core muscle activation and a person's ability to stabilize the lumbopelvic complex.Preparatory cues and images can be used to increase the activation of these muscles.To attain optimal movement patterns,it will be necessary to determine what cueing will give the most effective results for core stability.AIM To investigate the effects of external and internal cues on core muscle activation during the Sahrmann five-level core stability test.METHODS Total 68 participants(21.83±3.47 years)were randomly allocated to an external(n=35)or internal cue group(n=33).Participants performed the Sahrmann fivelevel core stability test without a cue as baseline and the five-level stability exercises with an internal or external cue.External cue group received a pressure biofeedback unit(PBU),and the internal cue group received an audio cue.A Delsys Trigno^(TM)surface electromyography unit was used for muscle activation from the rectus abdominis,external oblique,and transverse abdominis/internal oblique muscles.RESULTS Linear mixed effects model analysis showed that cueing had a significant effect on core muscle activation(P=0.001);however,there was no significant difference between cue types(internal or external)(P=0.130).CONCLUSION Both external and internal cueing have significant effects on core muscle activation during the Sahrmann five-level core stability test and the PBU does not create higher muscle activation than internal cueing.
文摘Background: Aging-induced cardiac hypertrophy and reduced skeletal muscle strength contribute to increased disease risk and life burden in the elderly. FNDC5 acts as a protective muscle factor in both cardiac and skeletal muscle. This study aims to examine the relationship between cardiac FNDC5 and aging-related cardiac hypertrophy and decreased skeletal muscle strength. Methods: Male young C57BL/6 mice (5 months old, n = 6) and aged mice (21 months old, n = 6) were utilized in the study and housed in a specific pathogen-free (SPF) environment. Prior to the experiment, grip strength tests were performed on the mice, and heart tissues were collected for morphological analysis, including the assessment of peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) and fibronectin type III-containing structural domain 5 (FNDC5) protein levels. Furthermore, myosin heavy chain II (MyHC II), skeletal muscle-specific transcription factor (MyoD), muscle RING-finger protein-1 (MuRF1), and FNDC5 levels were evaluated in the quadriceps muscle. The correlations between heart weight and FNDC5 expression levels, as well as skeletal muscle indices in the mice, were subsequently analyzed. Result: Aging leads to cardiac hypertrophy and reduced expression of PGC-1α and FNDC5 proteins. Concurrently, there is a decline in the strength of skeletal muscle, along with decreased expression of MyHC II and increased expression of MURF1 and MyoD. Correlation analysis demonstrated strong positive associations between myocardial FNDC5 protein levels and limb grip strength, as well as MyHC II, and strong negative associations with MyoD and MuRF1. Conclusion: There may be a significant association between aging-induced cardiac hypertrophy and decreased skeletal muscle strength, with FNDC5 potentially playing a crucial role as a regulatory molecule facilitating communication between the heart and skeletal muscle.
文摘The“longevity protein”SIRT5 could hold the key to delaying age-related muscle decline.A study led by researchers from the Institute of Zoology(IOZ)of the Chinese Academy of Sciences and Capital Medical University in Beijing reveals that SIRT5 mitigates skeletal muscle aging by blocking pro-inflammatory pathways.Published in Nature Metabolism on March 14,2025,the work identifies SIRT5’s interaction with protein kinase TBK1 as critical to preserving muscle mass and function.
基金supported by funding from the National Natural Science Foundation of China(82272478,82002330,82202728)the National Key R&D Program of China(No.2022YFF1100100)the Natural Science Foundation of Beijing(L222086).
文摘Systematic bone and muscle loss is a complex metabolic disease,which is frequently linked to gut dysfunction,yet its etiology and treatment remain elusive.While probiotics show promise in managing diseases through microbiome modulation,their therapeutic impact on gut dysfunction-induced bone and muscle loss remains to be elucidated.Employing dextran sulfate sodium(DSS)-induced gut dysfunction model and wide-spectrum antibiotics(ABX)-treated mice model,our study revealed that gut dysfunction instigates muscle and bone loss,accompanied by microbial imbalances.Importantly,Bifidobacterium animalis subsp.lactis A6(B.lactis A6)administration significantly ameliorated muscle and bone loss by modulating gut microbiota composition and enhancing butyrate-producing bacteria.This intervention effectively restored depleted butyrate levels in serum,muscle,and bone tissues caused by gut dysfunction.Furthermore,butyrate supplementation mitigated musculoskeletal loss by repairing the damaged intestinal barrier and enriching beneficial butyrate-producing bacteria.Importantly,butyrate inhibited the NF-κB pathway activation,and reduced the secretion of corresponding inflammatory factors in T cells.Our study highlights the critical role of dysbiosis in gut dysfunction-induced musculoskeletal loss and underscores the therapeutic potential of B.lactis A6.These discoveries offer new microbiome directions for translational and clinical research,providing promising strategies for preventing and managing musculoskeletal diseases.
文摘Sarcomerogenesis,the addition of serial sarcomeres in skeletal muscle myofibrils and fibres,is a natural occurrence during growth and maturation of animals,including humans.However,the detailed mechanisms that allow for sarcomerogenesis are not fully understood.In some diseases,such as cerebral palsy in children,sarcomerogenesis appears to be inhibited or at least reduced,1,2 often causing severe restrictions in muscle and joint function.
基金supported by the funded project(HYZHX M05005)in the field of space medical experiments of manned spaceflight engineering.
文摘Objective:To evaluate the efficacy and safety of transcutaneous electrical acupoint stimulation(TEAS)for muscle atrophy in patients with immobilization after surgical fixation of foot and ankle fractures.Methods:This was a two-arm randomized controlled trial wherein 80 patients were recruited and divided into control(n=40)and intervention(n=40)groups.The control group received conventional orthopedic treatment,whereas the intervention group received TEAS and conventional treatment.The intervention group received TEAS 3 times a week for 30 min each time for 8 weeks.The primary out-comes were muscle thickness(MT)and cross-sectional area(CSA)of the rectus femoris and gastroc-nemius muscles,whereas the secondary outcome measure was echo intensity(EI).Data were collected before the fixation operations(baseline assessment)and 4 and 8 weeks after intervention.Results:Compared with baseline,the MT and CSA were reduced in both groups by the end of treatment,whereas EI increased in both groups.At week 4,the reduction in the rectus femoris CSA in the inter-vention group was significantly lower than that in the control group(P=0.02);however,the between-group differences in the MT and EI(all P>0.05)were not significant.No serious adverse events were observed in either group.Conclusion:Our study showed that TEAS can improve muscle atrophy by attenuating the decline in the muscle CSA.Because this was only a pilot trial,subsequent studies will need longer follow-ups and larger sample sizes.
文摘Background:While muscle contractility increases with muscle temperature,there is no consensus on the best warm-up protocol to use before resistance training or sports exercise due to the range of possible warm-up and testing combinations available.Therefore,the objective of the current study was to determine the effects of different warm-up types(active,exercise-based vs.passive)on muscle function tested using different activation methods(voluntary vs.evoked)and performance test criteria(maximum force vs.rate-dependent contractile properties),with consideration of warm-up task specificity(specific vs.non-specific),temperature measurement method(muscle vs.skin),baseline temperatures,and subject-specific variables(training status and sex).Methods:A systematic search was conducted in PubMed/MEDLINE,Scopus,Web of Science,Cochrane,Embase,and ProQuest.Random-effects meta-analyses and meta-regressions were used to compute the effect sizes(ES)and 95%confidence intervals(95%CIs)to examine the effects of warm-up type,activation method,performance criterion,subject characteristics,and study design on temperature-related performance enhancement.Results:The search yielded 1272 articles,of which 33 met the inclusion criteria(n=921).Increasing temperature positively affected both voluntary(3.7%/℃±1.8%/℃(mean±SD),ES=0.28(95%CI:0.14 to 0.41))and evoked(3.2%/℃±1.5%/℃(mean±SD),ES=0.65(95%CI:0.29 to 1.00))rate-dependent contractile properties(dynamic,fast-velocity force production,and rate of force development(RFD))but not maximum force production(voluntary:-0.2%/℃±0.9%/℃(mean±SD),ES=0.08(95%CI:-0.05 to 0.22);evoked:-0.1%/℃±0.8%/℃(mean±SD),ES=-0.20(95%CI:-0.50 to 0.10)).Active warm-up did not induce greater enhancements in rate-dependent contractile properties(p=0.284),maximum force production(p=0.723),or overall function(pooled,p=0.093)than passive warm-up.Meta-regressions did not reveal a significant effect of study design,temperature measurement method,warm-up task specificity,training status,or sex on the effect of increasing temperature(p>0.05).Conclusion:Increasing muscle temperature significantly enhances rate-dependent contractile function(RFD and muscle power)but not maximum force in both evoked and voluntary contractions.In contrast to expectation,no effects of warm-up modality(active vs.passive)or temperature measurement method(muscle vs.skin)were detected,although insufficient data prevented robust sub-group analyses.
文摘1.Background When searching for the term“muscle power”on Google Scholar,about 3.7 million hits come up in 60 ms,and for the past 3 years,there were approximately 225 yearly peer-reviewed publications dealing with muscle power.Muscle power has been used to assess and predict athletic performance,to determine muscle rehabilitation following injury or disease,to measure functional decline as occurs in aging,and many other topics.
文摘It is a pleasure to contribute a commentary on the very interesting review by Dr.Orcioli-Silva and colleagues1 on the simultaneous measurements of cerebral cortex and muscle tissue oxygenation during exercise in healthy adults using near-infrared spectroscopy(NIRS).The first NIRS measurements of the cerebral cortex and muscle were performed on humans in 19772 and 1982,3 respectively.
基金supported by the National Natural Science Foundation of China(No.82172551)the Health Discipline Leader Project of Shanghai Municipal Health Commission(No.2022XD044),China.
文摘Skeletal muscle dysfunction is a common extrapulmonary comorbidity of chronic obstructive pulmonary disease(COPD) and is associated with decreased quality-of-life and survival in patients. The autophagy lysosome pathway is one of the proteolytic systems that significantly affect skeletal muscle structure and function. Intriguingly, both promoting and inhibiting autophagy have been observed to improve COPD skeletal muscle dysfunction, yet the mechanism is unclear. This paper first reviewed the effects of macroautophagy and mitophagy on the structure and function of skeletal muscle in COPD, and then explored the mechanism of autophagy mediating the dysfunction of skeletal muscle in COPD. The results showed that macroautophagy-and mitophagy-related proteins were significantly increased in COPD skeletal muscle. Promoting macroautophagy in COPD improves myogenesis and replication capacity of muscle satellite cells, while inhibiting macroautophagy in COPD myotubes increases their diameters. Mitophagy helps to maintain mitochondrial homeostasis by removing impaired mitochondria in COPD. Autophagy is a promising target for improving COPD skeletal muscle dysfunction, and further research should be conducted to elucidate the specific mechanisms by which autophagy mediates COPD skeletal muscle dysfunction, with the aim of enhancing our understanding in this field.
文摘BACKGROUND Poor musculoskeletal recovery following foot and ankle injury can result in chronic instability and persistent muscle weakness.Preliminary evidence has shown that blood flow restriction(BFR)rehabilitation can increase muscle strength and stability,helping to restore physical function and prevent repeated injury.AIM To determine whether BFR is more effective than traditional rehabilitation in improving muscle strength,size,and stability after foot and ankle injury.METHODS A systematic review and meta-analysis were performed.Articles were retrieved from MEDLINE,EMBASE,and CENTRAL databases.Included studies compared the effectiveness of BFR rehabilitation to traditional foot and ankle rehabilitation exercises.Eligible patients were those with a history of foot or ankle injury.Muscle strength,size,and dynamic balance were assessed by comparing impro vements in peak torque,cross-sectional area,and percent muscle activation.Methodological quality assessments were performed using the PEDro scale and Methodological Index for Non-Randomized Studies(MINORS).RESULTS Ten studies met the inclusion criteria.Five studies were of good to excellent quality according to the PEDro scale,and 5 studies were of moderate quality as per the MINORS criteria.Two studies compared the effect of BFR and non-BFR rehabilitation on muscle strength;the overall mean difference between the BRF and non-BFR groups was 0.09[95%CI:(0.05,0.12),P<0.0001].Two studies analyzed muscle activation following BFR and non-BFR rehabilitation;the overall mean difference between the BRF and non-BFR groups was 0.09[95%CI:(0.05,0.12),P<0.0001].Data on dynamic balance was synthesized from two studies;the mean difference between the BFR and control groups was 1.23[95%CI:(-1.55,4.01);P=0.39].CONCLUSION BFR rehabilitation is more effective than non-BFR rehabilitation at improving muscle strength and activation following foot and ankle injury.Additional studies are needed to develop a standardized BFR training protocol.
基金supported by the National Natural Science Foundation of China(32272895 and 32172744).
文摘Background While maternal proline(Pro)supplementation has demonstrated efficacy in enhancing placental angiogenesis and farrowing efficiency in swine,its regulatory role in fetal skeletal muscle ontogeny remains undefined.This study systematically evaluated the temporal-specific impacts of dietary Pro supplementation during critical phases of fetal myogenesis(encompassing primary myofiber formation and secondary myofiber hyperplasia)on offspring muscle development.A total of 120 sows with similar farrowing schedules were assigned to three groups:CON(basal diet),ST-Pro(0.5%Pro supplementation during secondary myofiber formation period,from d 60 gestation to farrowing),LT-Pro(0.5%Pro supplementation spanning primary and secondary myofiber formation period:from d 20 gestation to farrowing).Results LT-Pro group significantly increased the longissimus dorsi(LD)muscle mass per unit body weight in newborn piglets compared to CON group(P<0.05),while no such effect was observed in the ST-Pro group.Metabolomic profiling revealed elevated Pro,lysine,and tryptophan levels in the LD muscle of LT-Pro group piglets,accompanied by reduced branched-chain amino acids(BCAAs;leucine,isoleucine,and valine)in both serum and muscle(P<0.05).Histological analysis demonstrated a 45.74%increase in myofiber cross-sectional area in the LT-Pro group(P<0.05).At the molecular level,LT-Pro group piglets exhibited upregulated mRNA expression levels of myogenic regulatory genes(MYOD1,MYF6)and the cell cycle accelerator CCND1(P<0.05),coupled with activation of the STAT3 signaling pathway(phosphorylated STAT3 protein increased by 2.53-fold,P<0.01).Furthermore,Pro supplementation enhanced oxidative metabolism,evidenced by elevated mitochondrial biogenesis markers(the mRNA expression levels of PPARGC1A,OPA1,and SQSTM1)and a 61.58%increase in succinate dehydrogenase activity(P<0.05).Notably,LT-Pro group piglets showed a selective shift toward slow-twitch oxidative fibers,with both MyHC1 mRNA and protein expression levels significantly upregulated(P<0.05),while the mRNA expression levels of MyHCIIb showed no significant change.Conclusions This study identified the primary fiber formation period as a critical window.Supplementation with Pro during G20–114 reprogrammed offspring skeletal muscle development through STAT3-CCND1-mediated myoblast proliferation,enhanced mitochondrial bioenergetics,and oxidative fiber specification.However,no such effects were observed during G60–114.These findings propose maternal Pro intervention as a novel strategy to enhance muscle yield and metabolic efficiency in swine production,with potential applications for improving meat quality traits linked to oxidative muscle phenotypes.
文摘The maximal force a muscle can exert depends on its length,which has been explained by the sliding filament theory on the sarcomere level.1 A longer muscle can act over a greater range of motion and has more sarcomeres in series,which increases its capacity to produce force at a specific muscle contraction velocity because each sarcomere contracts at a lower velocity.
基金supported by the National Natural Science Foundation of China(No.52475067).
文摘Pneumatic artificial muscles(PAMs)can generate multimodal movements,e.g.,linear contraction/extension,spiral torsion,and bending motions.Among these motions,contraction and extension movements can be achieved using linear PAMs(LPAMs)designed to mimic human skeletal muscle.LPAMs have considerable potential for wearable applications and can be integrated into soft wearable robotic systems.Due to their inherent compliance,excellent human-robot interaction,safety,and low cost,LPAMs are considered potential alternatives as actuator components in the construction of wearable robots.This review presents a comprehensive overview of the bio-inspired design of LPAMs and their wearable applications.The biomechanics of human skeletal muscle,including anatomy,morphology,and biomechanical characterization,is analyzed to provide design inspirations for LPAMs and determine the assistance requirements of LPAM-based wearable robots.Herein,LPAMs are classified into four categories based on their structural shapes,including cylindrical-shaped muscles,flat-shaped muscles,fold-shaped muscles,and muscles with other shapes.In addition,this review provides an overview of the diverse physical interfaces utilized in wearable robots and presents a comparative analysis of the actuation characteristics of LPAMs and the assistance performance of LPAM-based wearable robots.This analysis was conducted in consideration of several key metrics,including the contraction ratio,maximum force,specific force,response frequency,assistive torque/bodyweight,and net metabolic cost.Finally,this review summarizes the ongoing challenges and future research directions.
基金supported in part by the Beijing Natural Science Foundation under Grant Nos.3232004 and 3222002in part by the National Natural Science Foundation of China under Grant Nos.62373010 and 52175001.
文摘Muscle strength training can effectively reduce muscle atrophy,activate muscle tissue and promote muscle strength recovery and growth.Based on our previous research,we developed four muscle strength training strategies by further imitating the clinical muscle strength training methods,namely,Isokinetic centriPetal-centriPetal Exercise(IPPE),Isokinetic centriPetal-centriFuge exercise(IPFE),Isokinetic centriFuge-centriPetal Exercise(IFPE)and Isokinetic centriFuge-centriFuge Exercise(IFFE).To quantitatively evaluate the performance of the developed strategies,experiments were carried out with elbow and knee joints as examples,and muscle Endurance Ratio(ER),Flexion and Extension torque ratio(F/E)and the degree of muscle activation were extracted and calculated based on angle/torque and Surface ElectroMyoGraphy(sEMG)signals.Experimental results showed that the ER value of IFFE was significantly reduced compared with IPPE,while the F/E value of IFPE was significantly increased;this suggests that muscle centrifugation corresponds to higher training intensity;In addition,flexor and extensor muscle groups showed different levels of muscle activation in different training strategies.The results reveal that combining different muscle movement characteristics,isokinetic exercise can exert special muscle strength training effects.The study can lay the foundation for exploring subject-specific adaptive muscle strength training strategies to better adapt to different levels of muscle strength.
