AIM:To evaluate the therapeutic effects of ranibizumab on optic disc and macular microvascular perfusion in central retinal vein occlusion(CRVO)with macular edema(ME).METHODS:Optical coherence tomography angiology(OCT...AIM:To evaluate the therapeutic effects of ranibizumab on optic disc and macular microvascular perfusion in central retinal vein occlusion(CRVO)with macular edema(ME).METHODS:Optical coherence tomography angiology(OCTA)parameters,including optic disc vessel density(VD;including whole-disc VD,intra-disc VD,and peripapillary VD),superficial/deep capillary plexus(SCP/DCP)VD,and central macular thickness(CMT)were analyzed.Additional assessments included best-corrected visual acuity(BCVA)via Early Treatment Diabetic Retinopathy Study(ETDRS)chart and hemorheological profiling.CRVO patients received monthly intravitreal ranibizumab injections for three consecutive months.Pre-and post-treatment parameters were statistically compared.RESULTS:The study comprised 60 CRVO-ME patients(28 males;32 females),aged 50-78y(mean 63.3±7.6y)and 60 age-/sex-matched healthy controls.As compared with participants exhibiting normal funduscopic findings,CRVO patients demonstrated significantly elevated levels of low-shear-rate whole blood viscosity(LSR-WBV),high-shearrate whole blood viscosity(HSR-WBV),and aggregation index(AI,all P<0.05).In CRVO-affected eyes,vertical cupto-disc(C/D)ratio and optic cup volume were significantly smaller,whereas retinal nerve fiber layer(RNFL)thickness was significantly greater,compared to both unaffected contralateral eyes and normal control eyes(all P<0.05).Following treatment,VD of the entire optic disc(P<0.05),intra-disc VD(P<0.05),and peripapillary VD(P<0.05)all increased significantly relative to baseline.CMT decreased significantly(P<0.05),whereas macular SCP-VD and macular DCP-VD showed non-significant slight reductions(P>0.05).At baseline,BCVA of CRVO eyes correlated with whole-disc VD(r=-0.276,P=0.033),intra-disc VD(r=-0.342,P=0.009),and peripapillary VD(r=-0.335,P=0.007),with intra-disc VD demonstrating the strongest association.Besides,BCVA improvement,after the treatment,correlated positively with whole-disc VD(r=0.342,P=0.008)and intradisc VD(r=0.396,P=0.002).CONCLUSION:Optic disc blood perfusion is more closely associated with visual acuity than macular perfusion,suggesting intra-disc VD may serve as a potential biomarker for monitoring visual acuity changes in CRVO.Multiple ranibizumab injections significantly improve optic disc perfusion but may have exerted detrimental effects on the macula.CRVO patients shows higher hemorheological parameters than those with normal fundi.Reduced vertical C/D ratio and optic cup volume may be linked to CRVO incidence,potentially acting as susceptibility factors.展开更多
Intervertebral disc degeneration is a major risk factor contributing to chronic low back and neck pain.While the etiological factors for disc degeneration vary,age is still one of the most important risk factors.Recen...Intervertebral disc degeneration is a major risk factor contributing to chronic low back and neck pain.While the etiological factors for disc degeneration vary,age is still one of the most important risk factors.Recent studies have shown the promising role of SIRT6 in mammalian aging and skeletal tissue health,however its role in the intervertebral disc health remains unexplored.We investigated the contribution of SIRT6 to disc health by studying the age-dependent spinal phenotype of mice with conditional deletion of Sirt6 in the disc(AcanCreERT2;Sirt6fl/fl).Histological studies showed a degenerative phenotype in knockout mice compared to Sirt6fl/fl control mice at 12 months,which became pronounced at 24 months.RNA-Seq analysis of NP and AF tissues,in vitro quantitative histone analysis,and RNA-seq with ATAC-seq multiomic studies revealed that SIRT6-loss resulted in changes in acetylation and methylation status of specific Histone 3 lysine residues and affected DNA accessibility and transcriptomic landscape.A decrease in autophagy and an increase in DNA damage were also noted in Sirt6-deficient cells.Further mechanistic insights revealed that loss of SIRT6 increased senescence and SASP burden in the disc characterized by increased p21,p19,γH2AX,IL-6,IL-1β,and TGF-βabundance.Taken together,our study highlights the contribution of SIRT6 in modulating DNA damage,autophagy,and cell senescence and its importance in maintaining disc health during aging,thereby underscoring it as a potential therapeutic target to treat intervertebral disc degeneration.展开更多
Background: Surgical treatment of lumbar disc herniation is a widely debated topic, with several techniques available. Percutaneous endoscopic discectomy (PELD) has gained popularity due to its lower invasiveness comp...Background: Surgical treatment of lumbar disc herniation is a widely debated topic, with several techniques available. Percutaneous endoscopic discectomy (PELD) has gained popularity due to its lower invasiveness compared to conventional techniques such as microdiscectomy/open lumbar microdiscectomy (OLMD)/tubular microdiscectomy (TMD). However, evidence on the effectiveness, recovery time and complications of these techniques is not yet clearly established. This systematic review aims to compare the preoperative and postoperative outcomes of both techniques. Methods: A comprehensive search was performed in databases including PubMed and Cochrane, following strict inclusion and exclusion criteria. Comparative studies and narrative reviews on PELD and OLMD/TMD published between 2019 and 2024 were included. Key outcomes considered were pre- and postoperative Visual Analogue Scale (VAS), hospitalization time, time to return to work, and postoperative complications. Results: The reviewed studies indicated that PELD is associated with a greater reduction in postoperative pain compared to OLMD/TMD, with a significant decrease in VAS, according to the study by Priola et al. (2019). The hospital stay was also shorter for patients undergoing PELD, averaging 2 days compared to OLMD/TMD. Furthermore, PELD favored a faster return to work and had a lower rate of postoperative complications, such as dural tears and reoperations, compared to OLMD/TMD. Conclusions: PELD demonstrates clear advantages over OLMD/TMD in terms of pain reduction, shorter hospital stay, faster return to work, and fewer postoperative complications. However, the implementation of this technique requires a significant learning curve, suggesting that its effectiveness may vary depending on the surgeon’s experience. PELD should be considered a preferred option in the resection of lumbar disc herniations, especially in patients seeking a quick and less invasive recovery.展开更多
Temporomandibular joint(TMJ)disc displacement is one of the most significant subtypes of temporomandibular joint disorders,but its etiology and mechanism are poorly understood.In this study,we elucidated the mechanism...Temporomandibular joint(TMJ)disc displacement is one of the most significant subtypes of temporomandibular joint disorders,but its etiology and mechanism are poorly understood.In this study,we elucidated the mechanisms by which destruction of inflamed collagen fibrils induces alterations in the mechanical properties and positioning of the TMJ disc.By constructing a rat model of TMJ arthritis,we observed anteriorly dislocated TMJ discs with aggravated deformity in vivo from five weeks to six months after a local injection of Freund’s complete adjuvant.By mimicking inflammatory conditions with interleukin-1 beta in vitro,we observed enhanced expression of collagen-synthesis markers in primary TMJ disc cells cultured in a conventional two-dimensional environment.In contrast,three-dimensional(3D)-cultivated disc cell sheets demonstrated the disordered assembly of inflamed collagen fibrils,inappropriate arrangement,and decreased Young’s modulus.Mechanistically,inflammation-related activation of the nuclear factor kappa-B(NF-κB)pathway occurs during the progression of TMJ arthritis.NF-κB inhibition reduced the collagen fibril destruction in the inflamed disc cell sheets in vitro,and early NF-κB blockade alleviated collagen degeneration and dislocation of the TMJ discs in vivo.Therefore,the NF-κB pathway participates in the collagen remodeling in inflamed TMJ discs,offering a potential therapeutic target for disc displacement.展开更多
Aging is a pivotal risk factor for intervertebral disc degeneration(IVDD)and chronic low back pain(LBP).The restoration of aging nucleus pulposus cells(NPCs)to a youthful epigenetic state is crucial for IVDD treatment...Aging is a pivotal risk factor for intervertebral disc degeneration(IVDD)and chronic low back pain(LBP).The restoration of aging nucleus pulposus cells(NPCs)to a youthful epigenetic state is crucial for IVDD treatment,but remains a formidable challenge.Here,we proposed a strategy to partially reprogram and reinstate youthful epigenetics of senescent NPCs by delivering a plasmid carrier that expressed pluripotency-associated genes(Oct4,Klf4 and Sox2)in Cavin2-modified exosomes(OKS@M-Exo)for treatment of IVDD and alleviating LBP.The functional OKS@M-Exo efficaciously alleviated senescence markers(p16^(INK4a),p21^(CIP1)and p53),reduced DNA damage and H4K20me3 expression,as well as restored proliferation ability and metabolic balance in senescent NPCs,as validated through in vitro experiments.In a rat model of IVDD,OKS@M-Exo maintained intervertebral disc height,nucleus pulposus hydration and tissue structure,effectively ameliorated IVDD via decreasing the senescence markers.Additionally,OKS@MExo reduced nociceptive behavior and downregulated nociception markers,indicating its efficiency in alleviating LBP.The transcriptome sequencing analysis also demonstrated that OKS@M-Exo could decrease the expression of age-related pathways and restore cell proliferation.Collectively,reprogramming by the OKS@M-Exo to restore youthful epigenetics of senescent NPCs may hold promise as a therapeutic platform to treat IVDD.展开更多
Background: Lumbar disc herniation is a common injury among athletes, especially those who practice disciplines with repetitive flexion movements, twisting and axial loading on the spine, such as weightlifting, gymnas...Background: Lumbar disc herniation is a common injury among athletes, especially those who practice disciplines with repetitive flexion movements, twisting and axial loading on the spine, such as weightlifting, gymnastics, hockey and American football. In refractory cases to conservative treatment, microscopic discectomy or full endoscopic discectomy are used as surgical options to relieve pain and restore patient functionality. However, the ideal time for a return to sports activities remains a matter of debate due to variations in recovery times and risks of complications associated with each technique. Methods: A review was conducted, including articles published in the last 33 years (1991-2024), as it was the earliest date matching our search criteria. Clinical studies, systematic reviews, meta-analyses, and clinical guidelines were included. Results: The most common complications when returning to sport prematurely include recurrence of the hernia, persistent pain (VAS leg 7 or higher after surgery) and reduced physical performance. The return to full activity rate of patients who underwent microdiscectomy reaches up to 90%, while the endoscopic technique shows a success rate that reaches 99%. Return to play meantime was 5.19 months (range 1.00 - 8.7 months) and mean time of 4.6 months (range 2 - 8 months) with Microdiscectomy and full endoscopic discectomy respectively. Conclusions: There is no unanimous consensus on the exact timing of return to sport due to variability in recovery times and clinical outcomes. In both techniques, evidence highlights the need for a multidisciplinary approach that integrates surgeons, physical therapists and trainers to optimize recovery and ensure a safe return.展开更多
Intervertebral disc degeneration(IVDD)is the primary contributor to a range of spinal diseases.Dynamin-related protein 1(Drp1)-mediated mitochondrial fission has recently been identified as a new cause of nucleus pulp...Intervertebral disc degeneration(IVDD)is the primary contributor to a range of spinal diseases.Dynamin-related protein 1(Drp1)-mediated mitochondrial fission has recently been identified as a new cause of nucleus pulposus cell(NPC)death and IVDD,but the underlying mechanisms remain unclear.Although the effects of Drp1 phosphorylation in IVDD have been studied,it is currently unknown if small ubiquitin-like modifications(SUMOylation)of Drp1 regulate IVDD.This study aimed to investigate the functions and mechanisms of mitochondria-anchored protein ligase(MAPL),a mitochondrial SUMO E3 ligase,during IVDD progression.The expression of genes related to SUMOylation and mitochondrial dynamics in TNF-α-stimulated NPCs was analysed via RNA sequencing.展开更多
Intervertebral disc degeneration(IDD)is a progressive and dynamic process in which the senescence-associated secretory phenotype(SASP)of nucleus pulposus cells(NPC)plays a significant role.While impaired chaperone-med...Intervertebral disc degeneration(IDD)is a progressive and dynamic process in which the senescence-associated secretory phenotype(SASP)of nucleus pulposus cells(NPC)plays a significant role.While impaired chaperone-mediated autophagy(CMA)has been associated with inflammation and cellular senescence,its specific involvement in the self-perpetuating feedback loop of NPC senescence remains poorly understood.Through LAMP2A knockout in NPC,we identified a significant upregulation of DYRK1A,a core mediator of premature senescence in Down syndrome.Subsequent validation established DYRK1A as the critical driver of premature senescence in CMA-deficient NPC.Combinatorial transcription factor analysis revealed that under IL1B stimulation or CMA inhibition,elevated DYRK1A promoted FOXC1 phosphorylation and nuclear translocation,initiating transcriptional activation of cell cycle arrest.Intriguingly,CMA impairment concurrently enhanced glutamine metabolic flux in senescent NPC,thereby augmenting their survival fitness.Transcriptomic profiling demonstrated that CMA reactivation in senescent NPC facilitated fate transition from senescence to apoptosis,mediated by decreased glutamine flux via GLUL degradation.Therefore,CMA exerts protective effects against IDD by maintaining equilibrium between premature senescence and senolysis.This study elucidates CMA’s regulatory role in SASP-mediated senescence amplification circuits,providing novel therapeutic insights for IDD and other age-related pathologies.展开更多
AIM:To compare the cup-to-disc ratio(CDR)and optic disc morphology between eyes with congenital cataract and eyes without cataract in children under 3 years old.METHODS:This study included 63 patients with bilateral c...AIM:To compare the cup-to-disc ratio(CDR)and optic disc morphology between eyes with congenital cataract and eyes without cataract in children under 3 years old.METHODS:This study included 63 patients with bilateral congenital cataract(mean age of 55.72±46.50wk,44 were male),33 patients with unilateral cataract(mean age of 56.63±33.23wk,16 were male),and 31 age-matched healthy children(mean age of 55.80±29.29wk,17 were male).Fundus photographs were taken with the RetCam 3 system.The horizontal-to-vertical disc diameter ratio(HVDR)was used as an index to describe the oval form of the optic disc.RESULTS:The horizontal cup-to-disc ratio(HCDR),vertical cup-to-disc ratio(VCDR)and HVDR of cataract eyes in unilateral groups were significantly smaller than those of the normal eyes(P<0.05).In the unilateral group,the HCDR,VCDR and HVDR of cataract eyes were significantly smaller than those in fellow eyes(P<0.05).The HVDR of eyes in the bilateral group was significantly smaller than those in the age-matched normal eyes(P<0.001).The form of optic disc of the cataract eyes in both the bilateral and unilateral groups was more vertical-oral than the normal eyes in the unilateral and the age-matched groups(P<0.05).CONCLUSION:Our results show that eyes with congenital cataract has a smaller HVDR and the form of the optic disc tended to be vertical-oval in young children.展开更多
In healthy intervertebral discs(IVDs),nerves and blood vessels are present only in the outer annulus fibrosus,while in degenerative IVDs,a large amount of nerve and blood vessel tissue grows inward.Evidence supports t...In healthy intervertebral discs(IVDs),nerves and blood vessels are present only in the outer annulus fibrosus,while in degenerative IVDs,a large amount of nerve and blood vessel tissue grows inward.Evidence supports that neurogenic inflammation produced by neuropeptides such as substance P and calcitonin gene related peptide released by the nociceptive nerve fibers innervating the IVDs plays a crucial role in the process of IVD degeneration.Recently,non-neuronal cells,including IVD cells and infiltrating immune cells,have emerged as important players in neurogenic inflammation.IVD cells and infiltrating immune cells express functional receptors for neuropeptides through which they receive signals from the nervous system.In return,IVD cells and immune cells produce neuropeptides and nerve growth factor,which stimulate nerve fibers.This communication generates a positive bidirectional feedback loop that can enhance the inflammatory response of the IVD.Recently emerging transient receptor potential channels have been recognized as contributors to neurogenic inflammation in the degenerative IVDs.These findings suggest that neurogenic inflammation involves complex pathophysiological interactions between sensory nerves and multiple cell types in the degenerative IVDs.Clarifying the mechanism of neurogenic inflammation in IVD degeneration may provide in-depth understanding of the pathology of discogenic low back pain.展开更多
Lumbar intervertebral disc degeneration is thought to be the main cause of low back pain,although the mechanisms by which it occurs and leads to pain remain unclear.In healthy adult discs,vessels and nerves are presen...Lumbar intervertebral disc degeneration is thought to be the main cause of low back pain,although the mechanisms by which it occurs and leads to pain remain unclear.In healthy adult discs,vessels and nerves are present only in the outer layer of the annulus fibrosus and in the bony endplate.Animal models,and histological and biomechanical studies have shown that annulus tear or endplate injury is the initiating factor for painful disc degeneration.Injury to the disc triggers a local inflammatory repair response that activates nociceptors and promotes the synthesis of neuropeptides such as substance P and calcitonin generelated peptide,by dorsal root ganglion neurons.These neuropeptides are transported to injured discs and act as pro-inflammatory molecules,promoting the production of an“inflammatory soup”by inducing vasodilatation and plasma extravasation as well as by promoting the release of chemical mediators from disc cells and infiltrating immune cells,causing neurogenic inflammation that leads to progressive disc degeneration and discogenic pain.展开更多
BACKGROUND Low back pain is a major cause of disability worldwide,with intervertebral disc degeneration contributing to nearly 40%of cases.Conventional treatments focus on symptom relief without addressing the underly...BACKGROUND Low back pain is a major cause of disability worldwide,with intervertebral disc degeneration contributing to nearly 40%of cases.Conventional treatments focus on symptom relief without addressing the underlying degeneration.Platelet-rich plasma(PRP),a regenerative therapy rich in growth factors,offers potential therapeutic benefits through growth factor-mediated mechanisms,though clinical evidence is limited.AIM To evaluate the efficacy of intradiscal autologous PRP injection in reducing pain and improving function in patients with chronic lumbar disc prolapse.METHODS This pilot quasi-experimental study was conducted in tertiary care centre between July 2022 and June 2024.The study involved comparing the outcomes between group A(n=17)who failed to respond to conservative treatment measures and received intradiscal PRP injection with group B(n=22)who responded to conservative treatment.Visual Analogue Scale(VAS)and Functional Rating Index(FRI)scores were recorded at baseline,3 weeks,and 6 weeks for both the groups.RESULTS Forty patients were enrolled in the study.The PRP group demonstrated significant improvement in VAS and FRI scores compared to baseline.While both groups improved from their respective baselines,direct between-group comparisons are limited by baseline differences in symptom severity.Patients who failed conservative trial showed significant improvement following PRP intervention,with outcomes approaching those observed in physiotherapy responders.CONCLUSION Intradiscal PRP injection significantly improved pain and function in patients with lumbar disc disease,with clinical improvements that approached the level observed in physiotherapy responders,despite baseline differences in symptom severity.PRP shows promise as an effective treatment for lumbar disc pathology;however,these preliminary findings are limited by the small sample size and short follow-up,warranting larger trials with long-term evaluation.展开更多
Chronic lower back pain(LBP)is the leading cause of disability worldwide.Due to its close relationship with intervertebral disc(IVD)degeneration(IVDD),research has historically focused more on understanding the mechan...Chronic lower back pain(LBP)is the leading cause of disability worldwide.Due to its close relationship with intervertebral disc(IVD)degeneration(IVDD),research has historically focused more on understanding the mechanism behind IVDD while clinical efforts prioritize pain management.More recently,there has been a shift toward understanding LBP as a distinct pathological entity.This review synthesizes current knowledge on discogenic LBP,combining known pathophysiology,molecular mechanisms,risk factors,diagnostic challenges,and available experimental models.IVDD is a complex,multifactorial process involving biochemical,mechanical,and inflammatory changes within the disc,leading to structural breakdown and potential discogenic pain.Key mechanisms include extracellular matrix degradation,upregulation of inflammatory mediators,immune cell infiltration,and aberrant nerve and vascular ingrowth.However,not all cases of IVDD result in LBP,highlighting the need for further investigation into the cellular,molecular,and biomechanical factors contributing to symptom development.Current diagnostic tools and experimental models for studying discogenic LBP remain limited,impeding the development of targeted treatments.Existing therapies primarily focus on symptom management rather than addressing underlying disease mechanisms.展开更多
BACKGROUND Far lateral lumbar disc herniation(FLLDH)is a special type of lumbar disc herniation with high rate of missed diagnosis.Selective nerve root block(SNRB)has special advantages in identifying the responsible ...BACKGROUND Far lateral lumbar disc herniation(FLLDH)is a special type of lumbar disc herniation with high rate of missed diagnosis.Selective nerve root block(SNRB)has special advantages in identifying the responsible nerve root.Percutaneous transforaminal endoscopic discectomy(PTED)is a minimally invasive and effective method to treat FLLDH.However,no report has investigated PTED combined with SNRB to treat FLLDH.AIM To explore the diagnosis and treatment process,surgical technique and clinical efficacy of PTED combined with SNRB to treat FLLDH.METHODS This is a multicenter center,retrospective,observational study.Between January 2020 and January 2022,32 patients were initially diagnosed with FLLDH.All the patients were identified using SNRB to determine the responsible segment and involved nerve roots.Because of poor symptomatic control following SNRB,2 patients were excluded.30 patients diagnosed with FFLDH underwent PTED.The clinical characteristics,operative and postoperative outcomes,complication and subsequent follow-up were collected.RESULTS 30 patients who underwent SNRB combined with PTED were followed up.The average visual analogue scale(VAS)-leg score,VAS-back score,Oswestry disability index(ODI)score at the Follow-up(1 day,1 month,3 months and last follow-up)were significantly different compared per-operation.According to the modified Macnab efficacy evaluation standard,the satisfaction degree at the last follow-up was excellent(28,93.33%),good(1,3.33%),medium(1,3.33%)and poor(0,0%).CONCLUSION SNRB provides an effective method for the definite diagnosis of FLDH and responsible nerve roots.Combination therapy offers several advantages including minimal invasiveness,precision,effectiveness,safety and low recurrence rates.展开更多
The ideal lumbar and cervical discs should provide six degrees of freedom andtri-planar (three-dimensional) motion. Although all artificial discs are intended toachieve the same goals, there is considerable heterogene...The ideal lumbar and cervical discs should provide six degrees of freedom andtri-planar (three-dimensional) motion. Although all artificial discs are intended toachieve the same goals, there is considerable heterogeneity in the design oflumbar and cervical implants. The “second generation total disc replacements”are non-articulating viscoelastic implants aiming at the reconstruction ofphysiologic levels of shock absorption and flexural stiffness. This review aims togive an overview of the available implants detailing the concepts and thefunctional results experimentally and clinically. These monobloc prostheses raisenew challenges concerning the choice of materials for the constitution of theviscoelastic cushion, the connection between the components of the internalstructure and the metal endplates and even the bone anchoring mode. Newobjectives concerning the quality of movement and mobility control must bedefined.展开更多
Intervertebral disc degeneration(IDD)results from an imbalance within the intervertebral disc,leading to alterations in extracellular matrix composition,loss of nucleus pulposus cells,increased oxidative stress,and in...Intervertebral disc degeneration(IDD)results from an imbalance within the intervertebral disc,leading to alterations in extracellular matrix composition,loss of nucleus pulposus cells,increased oxidative stress,and inflammatory cascade.While IDD naturally progresses with age,some factors such as mechanical trauma,lifestyle choices,and genetic abnormalities can elevate the risk of symptomatic disease progression.Current treatments,including pharmacological and surgical interventions,fail to halt disease progression or restore IDD function.Although biological therapies have been evaluated,their effectiveness in reversing long-term disc degeneration remains inconsistent.Mesenchymal stem cellbased therapies have demonstrated potential for IDD regeneration but are hindered by biological limitations,ethical issues,etc.To date,mesenchymal stem cell-derived extracellular vesicles(EVs)have emerged as promising therapeutic agents for regeneration and anti-inflammation.Their therapeutic effects are attributed to several mechanisms,such as the induction of regenerative phenotype,apoptosis mitigation,and immunomodulation.In addition,the abundance of microRNAs within EVs play a crucial role in modulating the disc degeneration.Due to the problems in clinical use,however,the efficiency of the EVs should be overcome further by optimizing cell culture conditions,engineering them to deliver drugs and targeting molecules,etc.展开更多
Pipeline Inspection Gauge(pig)is an important equipment for oil and gas pipelines during different stages of their operations to perform functions such as dewatering,cleaning,and inspection.Owing to the hyperelasticit...Pipeline Inspection Gauge(pig)is an important equipment for oil and gas pipelines during different stages of their operations to perform functions such as dewatering,cleaning,and inspection.Owing to the hyperelasticity,time and temperature-dependent material behaviour of the sealing disc attached on the pig,the contact between the pig and the pipeline expresses complex behaviour,leading to an uncertainty in the prediction of the pig's frictional force.Knowing the deformation of the sealing discs well is essential and can be highly meaningful for predicting the pig motion,as well as reducing the pigging risks.In this study,the geometrical deformation of the sealing discs with different sizes are investigated through experiments and numerical simulations.The effects of the four nondimensionalized parameters(interference,thickness per pipeline inner diameter,and clamping ratio)of the sealing discs on the deformation behaviour were observed and discussed,and an improved mathematical model for predicting the geometrical deformation of the sealing discs was proposed and verified.With the auxiliary angleαadded in the improved mathematical model,the relative error declines to 1.87%and 3.18%respectively for predicting deformation of the sealing discs in size of 2-inch and 40-inch pig.The results of this study can help better understand the frictional force of a pig with sealing discs,as well as its motion.展开更多
基金Central High-Level Traditional Chinese Medicine Hospital Project of Eye Hospital China Academy of Chinese Medical Science(No.GSP5-83,No.GSP4-02No.GSP5-06)+1 种基金Supported by National Natural Science Foundation of China(General ProgramNo.82474582).
文摘AIM:To evaluate the therapeutic effects of ranibizumab on optic disc and macular microvascular perfusion in central retinal vein occlusion(CRVO)with macular edema(ME).METHODS:Optical coherence tomography angiology(OCTA)parameters,including optic disc vessel density(VD;including whole-disc VD,intra-disc VD,and peripapillary VD),superficial/deep capillary plexus(SCP/DCP)VD,and central macular thickness(CMT)were analyzed.Additional assessments included best-corrected visual acuity(BCVA)via Early Treatment Diabetic Retinopathy Study(ETDRS)chart and hemorheological profiling.CRVO patients received monthly intravitreal ranibizumab injections for three consecutive months.Pre-and post-treatment parameters were statistically compared.RESULTS:The study comprised 60 CRVO-ME patients(28 males;32 females),aged 50-78y(mean 63.3±7.6y)and 60 age-/sex-matched healthy controls.As compared with participants exhibiting normal funduscopic findings,CRVO patients demonstrated significantly elevated levels of low-shear-rate whole blood viscosity(LSR-WBV),high-shearrate whole blood viscosity(HSR-WBV),and aggregation index(AI,all P<0.05).In CRVO-affected eyes,vertical cupto-disc(C/D)ratio and optic cup volume were significantly smaller,whereas retinal nerve fiber layer(RNFL)thickness was significantly greater,compared to both unaffected contralateral eyes and normal control eyes(all P<0.05).Following treatment,VD of the entire optic disc(P<0.05),intra-disc VD(P<0.05),and peripapillary VD(P<0.05)all increased significantly relative to baseline.CMT decreased significantly(P<0.05),whereas macular SCP-VD and macular DCP-VD showed non-significant slight reductions(P>0.05).At baseline,BCVA of CRVO eyes correlated with whole-disc VD(r=-0.276,P=0.033),intra-disc VD(r=-0.342,P=0.009),and peripapillary VD(r=-0.335,P=0.007),with intra-disc VD demonstrating the strongest association.Besides,BCVA improvement,after the treatment,correlated positively with whole-disc VD(r=0.342,P=0.008)and intradisc VD(r=0.396,P=0.002).CONCLUSION:Optic disc blood perfusion is more closely associated with visual acuity than macular perfusion,suggesting intra-disc VD may serve as a potential biomarker for monitoring visual acuity changes in CRVO.Multiple ranibizumab injections significantly improve optic disc perfusion but may have exerted detrimental effects on the macula.CRVO patients shows higher hemorheological parameters than those with normal fundi.Reduced vertical C/D ratio and optic cup volume may be linked to CRVO incidence,potentially acting as susceptibility factors.
基金supported by the Michael Michelson Gift FundNIA grants R01AG073349 (M.V.R.), R01AG044034 (R.F.L.), and R01AG078609 (J.C.)
文摘Intervertebral disc degeneration is a major risk factor contributing to chronic low back and neck pain.While the etiological factors for disc degeneration vary,age is still one of the most important risk factors.Recent studies have shown the promising role of SIRT6 in mammalian aging and skeletal tissue health,however its role in the intervertebral disc health remains unexplored.We investigated the contribution of SIRT6 to disc health by studying the age-dependent spinal phenotype of mice with conditional deletion of Sirt6 in the disc(AcanCreERT2;Sirt6fl/fl).Histological studies showed a degenerative phenotype in knockout mice compared to Sirt6fl/fl control mice at 12 months,which became pronounced at 24 months.RNA-Seq analysis of NP and AF tissues,in vitro quantitative histone analysis,and RNA-seq with ATAC-seq multiomic studies revealed that SIRT6-loss resulted in changes in acetylation and methylation status of specific Histone 3 lysine residues and affected DNA accessibility and transcriptomic landscape.A decrease in autophagy and an increase in DNA damage were also noted in Sirt6-deficient cells.Further mechanistic insights revealed that loss of SIRT6 increased senescence and SASP burden in the disc characterized by increased p21,p19,γH2AX,IL-6,IL-1β,and TGF-βabundance.Taken together,our study highlights the contribution of SIRT6 in modulating DNA damage,autophagy,and cell senescence and its importance in maintaining disc health during aging,thereby underscoring it as a potential therapeutic target to treat intervertebral disc degeneration.
文摘Background: Surgical treatment of lumbar disc herniation is a widely debated topic, with several techniques available. Percutaneous endoscopic discectomy (PELD) has gained popularity due to its lower invasiveness compared to conventional techniques such as microdiscectomy/open lumbar microdiscectomy (OLMD)/tubular microdiscectomy (TMD). However, evidence on the effectiveness, recovery time and complications of these techniques is not yet clearly established. This systematic review aims to compare the preoperative and postoperative outcomes of both techniques. Methods: A comprehensive search was performed in databases including PubMed and Cochrane, following strict inclusion and exclusion criteria. Comparative studies and narrative reviews on PELD and OLMD/TMD published between 2019 and 2024 were included. Key outcomes considered were pre- and postoperative Visual Analogue Scale (VAS), hospitalization time, time to return to work, and postoperative complications. Results: The reviewed studies indicated that PELD is associated with a greater reduction in postoperative pain compared to OLMD/TMD, with a significant decrease in VAS, according to the study by Priola et al. (2019). The hospital stay was also shorter for patients undergoing PELD, averaging 2 days compared to OLMD/TMD. Furthermore, PELD favored a faster return to work and had a lower rate of postoperative complications, such as dural tears and reoperations, compared to OLMD/TMD. Conclusions: PELD demonstrates clear advantages over OLMD/TMD in terms of pain reduction, shorter hospital stay, faster return to work, and fewer postoperative complications. However, the implementation of this technique requires a significant learning curve, suggesting that its effectiveness may vary depending on the surgeon’s experience. PELD should be considered a preferred option in the resection of lumbar disc herniations, especially in patients seeking a quick and less invasive recovery.
基金supported by the National Natural Science Foundation of China Nos.82370983,81671015(X.W.),82230030(Y.L.),82101043(S.C.)and 82370922(Y.F.)Beijing International Science and Technology Cooperation Project No.Z221100002722003(Y.L.)+4 种基金Beijing Natural Science Foundation Nos.L234017,JL23002(Y.L.),No.7242282(S.C.)and 7232217(Y.G.)Clinical Medicine Plus X-Young Scholars Project of Peking University No.PKU2024LCXQ039(Y.L.)National Program for Multidisciplinary Cooperative Treatment on Major Diseases No.PKUSSNMP-202013(X.W.)Hygiene and Health Development Scientific Research Fostering Plan of Haidian District Beijing No.HP2023-12-509001(J.Z.)Young Clinical Research Fund of the Chinese Stomatological Association No.CSA-02022-03(J.Z.).
文摘Temporomandibular joint(TMJ)disc displacement is one of the most significant subtypes of temporomandibular joint disorders,but its etiology and mechanism are poorly understood.In this study,we elucidated the mechanisms by which destruction of inflamed collagen fibrils induces alterations in the mechanical properties and positioning of the TMJ disc.By constructing a rat model of TMJ arthritis,we observed anteriorly dislocated TMJ discs with aggravated deformity in vivo from five weeks to six months after a local injection of Freund’s complete adjuvant.By mimicking inflammatory conditions with interleukin-1 beta in vitro,we observed enhanced expression of collagen-synthesis markers in primary TMJ disc cells cultured in a conventional two-dimensional environment.In contrast,three-dimensional(3D)-cultivated disc cell sheets demonstrated the disordered assembly of inflamed collagen fibrils,inappropriate arrangement,and decreased Young’s modulus.Mechanistically,inflammation-related activation of the nuclear factor kappa-B(NF-κB)pathway occurs during the progression of TMJ arthritis.NF-κB inhibition reduced the collagen fibril destruction in the inflamed disc cell sheets in vitro,and early NF-κB blockade alleviated collagen degeneration and dislocation of the TMJ discs in vivo.Therefore,the NF-κB pathway participates in the collagen remodeling in inflamed TMJ discs,offering a potential therapeutic target for disc displacement.
基金supported by the Ministry of Science and Technology of China(2020YFA0908900)National Natural Science Foundation of China(21935011 and 82072490)+1 种基金Shenzhen Science and Technology Innovation Commission(KQTD20200820113012029 and KJZD20230923114612025)Guangdong Provincial Key Laboratory of Advanced Biomaterials(2022B1212010003).
文摘Aging is a pivotal risk factor for intervertebral disc degeneration(IVDD)and chronic low back pain(LBP).The restoration of aging nucleus pulposus cells(NPCs)to a youthful epigenetic state is crucial for IVDD treatment,but remains a formidable challenge.Here,we proposed a strategy to partially reprogram and reinstate youthful epigenetics of senescent NPCs by delivering a plasmid carrier that expressed pluripotency-associated genes(Oct4,Klf4 and Sox2)in Cavin2-modified exosomes(OKS@M-Exo)for treatment of IVDD and alleviating LBP.The functional OKS@M-Exo efficaciously alleviated senescence markers(p16^(INK4a),p21^(CIP1)and p53),reduced DNA damage and H4K20me3 expression,as well as restored proliferation ability and metabolic balance in senescent NPCs,as validated through in vitro experiments.In a rat model of IVDD,OKS@M-Exo maintained intervertebral disc height,nucleus pulposus hydration and tissue structure,effectively ameliorated IVDD via decreasing the senescence markers.Additionally,OKS@MExo reduced nociceptive behavior and downregulated nociception markers,indicating its efficiency in alleviating LBP.The transcriptome sequencing analysis also demonstrated that OKS@M-Exo could decrease the expression of age-related pathways and restore cell proliferation.Collectively,reprogramming by the OKS@M-Exo to restore youthful epigenetics of senescent NPCs may hold promise as a therapeutic platform to treat IVDD.
文摘Background: Lumbar disc herniation is a common injury among athletes, especially those who practice disciplines with repetitive flexion movements, twisting and axial loading on the spine, such as weightlifting, gymnastics, hockey and American football. In refractory cases to conservative treatment, microscopic discectomy or full endoscopic discectomy are used as surgical options to relieve pain and restore patient functionality. However, the ideal time for a return to sports activities remains a matter of debate due to variations in recovery times and risks of complications associated with each technique. Methods: A review was conducted, including articles published in the last 33 years (1991-2024), as it was the earliest date matching our search criteria. Clinical studies, systematic reviews, meta-analyses, and clinical guidelines were included. Results: The most common complications when returning to sport prematurely include recurrence of the hernia, persistent pain (VAS leg 7 or higher after surgery) and reduced physical performance. The return to full activity rate of patients who underwent microdiscectomy reaches up to 90%, while the endoscopic technique shows a success rate that reaches 99%. Return to play meantime was 5.19 months (range 1.00 - 8.7 months) and mean time of 4.6 months (range 2 - 8 months) with Microdiscectomy and full endoscopic discectomy respectively. Conclusions: There is no unanimous consensus on the exact timing of return to sport due to variability in recovery times and clinical outcomes. In both techniques, evidence highlights the need for a multidisciplinary approach that integrates surgeons, physical therapists and trainers to optimize recovery and ensure a safe return.
基金supported by National Natural Science Foundation of China(82272549,82472505,and 82472498)National key Research and Development plan,Ministry of Science and Technology of the People’s Republic of China(2022YFC2407203)+2 种基金the Young Health Talents of Shanghai Municipal Health Commission,China(2022YQ011)China Medical Education Association(3030537245)The Youth Talent Project of Huashan Hospital(30302164006).
文摘Intervertebral disc degeneration(IVDD)is the primary contributor to a range of spinal diseases.Dynamin-related protein 1(Drp1)-mediated mitochondrial fission has recently been identified as a new cause of nucleus pulposus cell(NPC)death and IVDD,but the underlying mechanisms remain unclear.Although the effects of Drp1 phosphorylation in IVDD have been studied,it is currently unknown if small ubiquitin-like modifications(SUMOylation)of Drp1 regulate IVDD.This study aimed to investigate the functions and mechanisms of mitochondria-anchored protein ligase(MAPL),a mitochondrial SUMO E3 ligase,during IVDD progression.The expression of genes related to SUMOylation and mitochondrial dynamics in TNF-α-stimulated NPCs was analysed via RNA sequencing.
基金supported by the National Natural Science Foundation of China (NSFC) (No.82172497)
文摘Intervertebral disc degeneration(IDD)is a progressive and dynamic process in which the senescence-associated secretory phenotype(SASP)of nucleus pulposus cells(NPC)plays a significant role.While impaired chaperone-mediated autophagy(CMA)has been associated with inflammation and cellular senescence,its specific involvement in the self-perpetuating feedback loop of NPC senescence remains poorly understood.Through LAMP2A knockout in NPC,we identified a significant upregulation of DYRK1A,a core mediator of premature senescence in Down syndrome.Subsequent validation established DYRK1A as the critical driver of premature senescence in CMA-deficient NPC.Combinatorial transcription factor analysis revealed that under IL1B stimulation or CMA inhibition,elevated DYRK1A promoted FOXC1 phosphorylation and nuclear translocation,initiating transcriptional activation of cell cycle arrest.Intriguingly,CMA impairment concurrently enhanced glutamine metabolic flux in senescent NPC,thereby augmenting their survival fitness.Transcriptomic profiling demonstrated that CMA reactivation in senescent NPC facilitated fate transition from senescence to apoptosis,mediated by decreased glutamine flux via GLUL degradation.Therefore,CMA exerts protective effects against IDD by maintaining equilibrium between premature senescence and senolysis.This study elucidates CMA’s regulatory role in SASP-mediated senescence amplification circuits,providing novel therapeutic insights for IDD and other age-related pathologies.
文摘AIM:To compare the cup-to-disc ratio(CDR)and optic disc morphology between eyes with congenital cataract and eyes without cataract in children under 3 years old.METHODS:This study included 63 patients with bilateral congenital cataract(mean age of 55.72±46.50wk,44 were male),33 patients with unilateral cataract(mean age of 56.63±33.23wk,16 were male),and 31 age-matched healthy children(mean age of 55.80±29.29wk,17 were male).Fundus photographs were taken with the RetCam 3 system.The horizontal-to-vertical disc diameter ratio(HVDR)was used as an index to describe the oval form of the optic disc.RESULTS:The horizontal cup-to-disc ratio(HCDR),vertical cup-to-disc ratio(VCDR)and HVDR of cataract eyes in unilateral groups were significantly smaller than those of the normal eyes(P<0.05).In the unilateral group,the HCDR,VCDR and HVDR of cataract eyes were significantly smaller than those in fellow eyes(P<0.05).The HVDR of eyes in the bilateral group was significantly smaller than those in the age-matched normal eyes(P<0.001).The form of optic disc of the cataract eyes in both the bilateral and unilateral groups was more vertical-oral than the normal eyes in the unilateral and the age-matched groups(P<0.05).CONCLUSION:Our results show that eyes with congenital cataract has a smaller HVDR and the form of the optic disc tended to be vertical-oval in young children.
文摘In healthy intervertebral discs(IVDs),nerves and blood vessels are present only in the outer annulus fibrosus,while in degenerative IVDs,a large amount of nerve and blood vessel tissue grows inward.Evidence supports that neurogenic inflammation produced by neuropeptides such as substance P and calcitonin gene related peptide released by the nociceptive nerve fibers innervating the IVDs plays a crucial role in the process of IVD degeneration.Recently,non-neuronal cells,including IVD cells and infiltrating immune cells,have emerged as important players in neurogenic inflammation.IVD cells and infiltrating immune cells express functional receptors for neuropeptides through which they receive signals from the nervous system.In return,IVD cells and immune cells produce neuropeptides and nerve growth factor,which stimulate nerve fibers.This communication generates a positive bidirectional feedback loop that can enhance the inflammatory response of the IVD.Recently emerging transient receptor potential channels have been recognized as contributors to neurogenic inflammation in the degenerative IVDs.These findings suggest that neurogenic inflammation involves complex pathophysiological interactions between sensory nerves and multiple cell types in the degenerative IVDs.Clarifying the mechanism of neurogenic inflammation in IVD degeneration may provide in-depth understanding of the pathology of discogenic low back pain.
文摘Lumbar intervertebral disc degeneration is thought to be the main cause of low back pain,although the mechanisms by which it occurs and leads to pain remain unclear.In healthy adult discs,vessels and nerves are present only in the outer layer of the annulus fibrosus and in the bony endplate.Animal models,and histological and biomechanical studies have shown that annulus tear or endplate injury is the initiating factor for painful disc degeneration.Injury to the disc triggers a local inflammatory repair response that activates nociceptors and promotes the synthesis of neuropeptides such as substance P and calcitonin generelated peptide,by dorsal root ganglion neurons.These neuropeptides are transported to injured discs and act as pro-inflammatory molecules,promoting the production of an“inflammatory soup”by inducing vasodilatation and plasma extravasation as well as by promoting the release of chemical mediators from disc cells and infiltrating immune cells,causing neurogenic inflammation that leads to progressive disc degeneration and discogenic pain.
文摘BACKGROUND Low back pain is a major cause of disability worldwide,with intervertebral disc degeneration contributing to nearly 40%of cases.Conventional treatments focus on symptom relief without addressing the underlying degeneration.Platelet-rich plasma(PRP),a regenerative therapy rich in growth factors,offers potential therapeutic benefits through growth factor-mediated mechanisms,though clinical evidence is limited.AIM To evaluate the efficacy of intradiscal autologous PRP injection in reducing pain and improving function in patients with chronic lumbar disc prolapse.METHODS This pilot quasi-experimental study was conducted in tertiary care centre between July 2022 and June 2024.The study involved comparing the outcomes between group A(n=17)who failed to respond to conservative treatment measures and received intradiscal PRP injection with group B(n=22)who responded to conservative treatment.Visual Analogue Scale(VAS)and Functional Rating Index(FRI)scores were recorded at baseline,3 weeks,and 6 weeks for both the groups.RESULTS Forty patients were enrolled in the study.The PRP group demonstrated significant improvement in VAS and FRI scores compared to baseline.While both groups improved from their respective baselines,direct between-group comparisons are limited by baseline differences in symptom severity.Patients who failed conservative trial showed significant improvement following PRP intervention,with outcomes approaching those observed in physiotherapy responders.CONCLUSION Intradiscal PRP injection significantly improved pain and function in patients with lumbar disc disease,with clinical improvements that approached the level observed in physiotherapy responders,despite baseline differences in symptom severity.PRP shows promise as an effective treatment for lumbar disc pathology;however,these preliminary findings are limited by the small sample size and short follow-up,warranting larger trials with long-term evaluation.
基金supported by the California Institute for Regenerative Medicine under EDUC4-12751(Giselle Kaneda)DISC2-14049(Dmitriy Sheyn)+1 种基金Additional support was provided by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under award numbers R01AR066517(Debiao Li)R01AR082041(Dmitriy Sheyn).
文摘Chronic lower back pain(LBP)is the leading cause of disability worldwide.Due to its close relationship with intervertebral disc(IVD)degeneration(IVDD),research has historically focused more on understanding the mechanism behind IVDD while clinical efforts prioritize pain management.More recently,there has been a shift toward understanding LBP as a distinct pathological entity.This review synthesizes current knowledge on discogenic LBP,combining known pathophysiology,molecular mechanisms,risk factors,diagnostic challenges,and available experimental models.IVDD is a complex,multifactorial process involving biochemical,mechanical,and inflammatory changes within the disc,leading to structural breakdown and potential discogenic pain.Key mechanisms include extracellular matrix degradation,upregulation of inflammatory mediators,immune cell infiltration,and aberrant nerve and vascular ingrowth.However,not all cases of IVDD result in LBP,highlighting the need for further investigation into the cellular,molecular,and biomechanical factors contributing to symptom development.Current diagnostic tools and experimental models for studying discogenic LBP remain limited,impeding the development of targeted treatments.Existing therapies primarily focus on symptom management rather than addressing underlying disease mechanisms.
基金Supported by the National Key R&D Program of China,No.Key Special Project for Marine Environmental Security and Sustainable Development of Coral Reefs 2022-3.5the National Natural Science Foundation of China,No.82102605,82472458,and 82272533.
文摘BACKGROUND Far lateral lumbar disc herniation(FLLDH)is a special type of lumbar disc herniation with high rate of missed diagnosis.Selective nerve root block(SNRB)has special advantages in identifying the responsible nerve root.Percutaneous transforaminal endoscopic discectomy(PTED)is a minimally invasive and effective method to treat FLLDH.However,no report has investigated PTED combined with SNRB to treat FLLDH.AIM To explore the diagnosis and treatment process,surgical technique and clinical efficacy of PTED combined with SNRB to treat FLLDH.METHODS This is a multicenter center,retrospective,observational study.Between January 2020 and January 2022,32 patients were initially diagnosed with FLLDH.All the patients were identified using SNRB to determine the responsible segment and involved nerve roots.Because of poor symptomatic control following SNRB,2 patients were excluded.30 patients diagnosed with FFLDH underwent PTED.The clinical characteristics,operative and postoperative outcomes,complication and subsequent follow-up were collected.RESULTS 30 patients who underwent SNRB combined with PTED were followed up.The average visual analogue scale(VAS)-leg score,VAS-back score,Oswestry disability index(ODI)score at the Follow-up(1 day,1 month,3 months and last follow-up)were significantly different compared per-operation.According to the modified Macnab efficacy evaluation standard,the satisfaction degree at the last follow-up was excellent(28,93.33%),good(1,3.33%),medium(1,3.33%)and poor(0,0%).CONCLUSION SNRB provides an effective method for the definite diagnosis of FLDH and responsible nerve roots.Combination therapy offers several advantages including minimal invasiveness,precision,effectiveness,safety and low recurrence rates.
文摘The ideal lumbar and cervical discs should provide six degrees of freedom andtri-planar (three-dimensional) motion. Although all artificial discs are intended toachieve the same goals, there is considerable heterogeneity in the design oflumbar and cervical implants. The “second generation total disc replacements”are non-articulating viscoelastic implants aiming at the reconstruction ofphysiologic levels of shock absorption and flexural stiffness. This review aims togive an overview of the available implants detailing the concepts and thefunctional results experimentally and clinically. These monobloc prostheses raisenew challenges concerning the choice of materials for the constitution of theviscoelastic cushion, the connection between the components of the internalstructure and the metal endplates and even the bone anchoring mode. Newobjectives concerning the quality of movement and mobility control must bedefined.
基金Supported by 2024 Yeungnam University Grant,No.224A480005.
文摘Intervertebral disc degeneration(IDD)results from an imbalance within the intervertebral disc,leading to alterations in extracellular matrix composition,loss of nucleus pulposus cells,increased oxidative stress,and inflammatory cascade.While IDD naturally progresses with age,some factors such as mechanical trauma,lifestyle choices,and genetic abnormalities can elevate the risk of symptomatic disease progression.Current treatments,including pharmacological and surgical interventions,fail to halt disease progression or restore IDD function.Although biological therapies have been evaluated,their effectiveness in reversing long-term disc degeneration remains inconsistent.Mesenchymal stem cellbased therapies have demonstrated potential for IDD regeneration but are hindered by biological limitations,ethical issues,etc.To date,mesenchymal stem cell-derived extracellular vesicles(EVs)have emerged as promising therapeutic agents for regeneration and anti-inflammation.Their therapeutic effects are attributed to several mechanisms,such as the induction of regenerative phenotype,apoptosis mitigation,and immunomodulation.In addition,the abundance of microRNAs within EVs play a crucial role in modulating the disc degeneration.Due to the problems in clinical use,however,the efficiency of the EVs should be overcome further by optimizing cell culture conditions,engineering them to deliver drugs and targeting molecules,etc.
基金supported by Key Technologies Research and Development Program(Grant No.SQ2022YFC2806103)and the National Natural Science Foundation of China(Grant No.51509259).
文摘Pipeline Inspection Gauge(pig)is an important equipment for oil and gas pipelines during different stages of their operations to perform functions such as dewatering,cleaning,and inspection.Owing to the hyperelasticity,time and temperature-dependent material behaviour of the sealing disc attached on the pig,the contact between the pig and the pipeline expresses complex behaviour,leading to an uncertainty in the prediction of the pig's frictional force.Knowing the deformation of the sealing discs well is essential and can be highly meaningful for predicting the pig motion,as well as reducing the pigging risks.In this study,the geometrical deformation of the sealing discs with different sizes are investigated through experiments and numerical simulations.The effects of the four nondimensionalized parameters(interference,thickness per pipeline inner diameter,and clamping ratio)of the sealing discs on the deformation behaviour were observed and discussed,and an improved mathematical model for predicting the geometrical deformation of the sealing discs was proposed and verified.With the auxiliary angleαadded in the improved mathematical model,the relative error declines to 1.87%and 3.18%respectively for predicting deformation of the sealing discs in size of 2-inch and 40-inch pig.The results of this study can help better understand the frictional force of a pig with sealing discs,as well as its motion.
