BACKGROUND:Muscle aging is closely related to various epigenetic changes,and exercise has a certain regulatory effect on these epigenetic changes.However,the specific mechanism is not fully understood. OBJECTIVE:To review the epigenetic mechanisms of skeletal muscle and how exercise can improve skeletal muscle aging and promote adaptive changes in muscle through these epigenetic mechanisms,aiming to provide a more comprehensive understanding of skeletal muscle aging and disease mechanisms. METHODS:During the period from June 1st to August 1st,2023,literature searches were conducted for relevant literature published from database inception to August 2023 in databases including Web of Science,PubMed,CNKI,WanFang,and VIP.The search terms used included"skeletal muscle,""muscle,""aging,""older adult,""aging,""exercise,""physical exercise,""epigenetic,"and"epigenetics"in Chinese as well as"skeletal muscle,muscle,aging,older adult,senescence,age,exercise,sports,physical activity,epigenetic,epigenetics"in English.Boolean logic operators were used to connect the search terms for retrieval,and corresponding strategies were developed.According to the predetermined inclusion and exclusion criteria,70 eligible articles were selected. RESULTS AND CONCLUSION:Epigenetics refers to the phenomenon where gene expression and function are regulated without changes in gene sequence,and epigenetic changes in skeletal muscle are an important field.The epigenetic mechanisms of skeletal muscle play an important role in muscle aging,mainly involving DNA methylation,histone modification,regulation of non-coding RNAs,chromatin remodeling,changes in mitochondrial function and expression changes of aging-related genes.Exercise significantly regulates the epigenetics of skeletal muscle,including promoting DNA methylation,muscle histone modification,regulating miRNA expression,and regulating lncRNA expression,regulating muscle factors(such as interleukin-6),regulating mitochondrial function(such as peroxisome proliferators-activated receptors γ co-activator 1α).Future studies are recommended for long-term,cross-diverse population-based exercise interventions;the application of multi-omics techniques such as proteomics and metabolomics;strengthening the understanding of epigenetic changes at the single-cell level;cross-species comparative studies as well as human clinical trials for the translation of animal model findings to humans;strategies for combining exercise and pharmacological interventions to assess their synergistic effects;and epigenetic studies of crosstalk interactions between skeletal muscle and different organs.

BACKGROUND:Dysfunction of macrophage efferocytosis can induce local and systemic inflammatory damage and is associated with a variety of obesity-related metabolic diseases.Moreover,compounds targeting efferocytosis have shown good therapeutic effects. OBJECTIVE:By reviewing the effects of obesity on macrophage efferocytosis,to analyze the key mechanism by which obesity inhibits efferocytosis,to summarize the research progress in compounds targeting efferocytosis to treat obesity-related metabolic diseases,so as to provide new ideas for fully understanding efferocytosis and its relationship with metabolic diseases,aiming to provide new strategies for disease prevention and treatment. METHODS:The English search terms were"efferocytosis,metabolism,obesity,obese,atherosclerosis,non-alcoholic steatohepatitis,neurodegeneration,tumor,osteoarthritis,diabetes,compound,medicine,treatment,"which were used for literature retrieval in PubMed and Web of Science.The Chinese search term was"efferocytosis,"which was used for literature retrieval in CNKI,VIP and WanFang datebases.Ninety-nine papers were finally included in the review analysis after a rigorous screening process. RESULTS AND CONCLUSION:In the process of efferocytosis,the"Find me"and"Eat me"processes involving a large number of apoptotic cell derived factors are mainly regulated by apoptotic cells.The efferocytosis factor involved in cytoskeletal remodeling and digestion are mainly derived from macrophages,which are crucial for efferocytosis activity.These results suggest that the"Find me"and"Eat me"factors mainly reflect the condition of apoptosis,and it is more scientific to select the expression of factors involved in cytoskeletal remodeling and digestion when evaluating the efferocytosis activity of macrophages.Obesity inhibits efferocytosis,and shows an inhibitory effect on most digestive factors,but has a stress-induced activation effect on most"Find me,""Eat me"and cytoskeletal recombination factors,which further indicates the decisive effect of digestive stage on efferocytosis and suggests that it is not reliable for some studies to evaluate the efferocytosis based on the increased expression of"Find me"and"Eat me"factors.Targeting cytokines in the digestive phase may be more effective when discussing future intervention strategies targeting macrophages efferocytosis.The efferocytosis activators of macrophages are effective in the treatment of various metabolic diseases,but the efferocytosis inhibitors in tumor tissue show good anticancer effects,suggesting that the role of efferocytosis should be rationally evaluated according to the characteristics of tissue inflammation.Efferocytosis is a relatively new concept proposed in 2003,with a short research history and complex efferocytosis factors.Current studies on obesity and efferocytosis only involve a tip of the iceberg and most of them are at a superficial level and a large number of scientific experiments are needed to further validate the mechanisms.

BACKGROUND:Cervical rotation-traction manipulation is effective and safe in the treatment of cervical spondylotic radiculopathy,and has been widely used in clinical work.However,its effects on the biomechanics of cervical vertebra and intervertebral disc and the area of intervertebral foramen have not been systematically clarified. OBJECTIVE:Based on the finite element analysis technique,a relevant research and analysis were carried out to provide digital evidence for the mechanism of effect of cervical rotation-traction manipulation in the treatment of cervical spondylotic radiculopathy. METHODS:The CT image data of a volunteer with no neck diseases were selected as the finite element model material at its left-handed physiological limit position.The initial construction of the finite element model was completed by Mimics 19.0 software,Geomagic Studio 2013 software,Hypermash 14.0 software,and ANSYS Workbench 2020 R2 software,respectively.Based on the literature,the grid division of cervical structure and the assignment of elastic modulus and elastic coefficient were completed.Based on the previous work of the team,the mechanical effects of cervical rotation-traction manipulation were simulated on the model.Effects of cervical rotation-traction manipulation on the mechanical parameters of each vertebral body and intervertebral disc in C3-T1 segment and on the cervical lateral foramen area were analyzed. RESULTS AND CONCLUSION:(1)During cervical rotation-traction manipulation,the stress of bone structure was significantly higher than that of soft tissue such as intervertebral disc.(2)When operating the technique,the stress at the top of each cervical vertebra was higher,the stress at the bottom was lower,and the stress at the facet joint and transverse process was lower.The stress at the top of the intervertebral disc was lower,the stress at the bottom was higher,but the highest point of the intervertebral disc stress was outside the top.(3)In addition,after loading the lifting force,the projected area of the C6/C7 intervertebral foramen increased significantly compared with that before loading.(4)It is indicated that the cervical rotation-traction manipulation has the mechanical characteristics of changing the stress structure of the cervical spine itself,and can expand the C6/7 intervertebral cervical foramen area on the opposite side of the patient's cervical rotation,so as to achieve the purpose of treating cervical spondylotic radiculopathy.

BACKGROUND:Cervical disc herniation can cause pain in the neck and shoulder area,as well as radiating pain in the upper limbs.The incidence rate is increasing year by year and tends to affect younger individuals.Fully understanding the biomechanical characteristics of the cervical spine in adolescents is of great significance for preventing and delaying the onset of cervical disc herniation in this age group. OBJECTIVE:To reconstruct cervical spine models for both healthy adolescents and adolescent patients with cervical disc herniation utilizing finite element analysis techniques,to analyze the motion range of the C1-T1 cervical vertebrae as well as the biomechanical characteristics of the annulus fibrosus,nucleus pulposus,endplates,and the cartilage of the small joints. METHODS:A normal adolescent's cervical spine and an adolescent patient with cervical disc herniation were selected in this study.The continuous scan cervical spine CT raw image data were imported into Mimics 21.0 in DICOM format.The C1-T1 vertebrae were reconstructed separately.Subsequently,the established models were imported into the 3-Matic software for disc reconstruction.The perfected models were then imported into Hypermesh software for meshing of the vertebrae,nucleus pulposus,annulus fibrosus,and ligaments,creating valid geometric models.After assigning material properties,the final models were imported into ABAQUS software to observe the joint motion range of the C1-C7 cervical vertebrae segments under different conditions,and to analyze the biomechanical characteristics of the annulus fibrosus,nucleus pulposus,endplates,and small joint cartilage of each cervical spine segment. RESULTS AND CONCLUSION:(1)In six different conditions,the joint motion range of the C1 vertebra in the cervical spine models of both normal adolescent and adolescent patient with cervical disc herniation was higher than that of the other vertebrae.Additionally,the joint motion range of each cervical spine segment in normal adolescent was greater than that in adolescent patient with cervical disc herniation.(2)In the cervical spine model of normal adolescent,the maximum stress values in the annulus fibrosus and nucleus pulposus were found on the left side during C2-3 flexion conditions(0.43 MPa and 0.17 MPa,respectively).In the cervical spine model of adolescent patient with cervical disc herniation,the maximum stress values were found on the left side during C7-T1 flexion conditions(0.54 MPa and 0.18 MPa,respectively).(3)In the cervical spine model of normal adolescent,the maximum stress value on the endplate was found on the left side of the upper endplate of C3 during flexion conditions(1.46 MPa).In the model of adolescent patient with cervical disc herniation,the maximum stress value on the endplate was found on the left side of the lower endplate of C7 during flexion conditions(1.32 MPa).(4)In the cervical spine model of normal adolescent,the maximum stress value in the small joint cartilage was found in the C2-3 left rotation conditions(0.98 MPa).In adolescent patient with cervical disc herniation,the stress in the small joint cartilage significantly increased under different conditions,especially in C1-2,with the maximum stress found during left flexion(3.50 MPa).(5)It is concluded that compared to normal adolescent,adolescent patient with cervical disc herniation exhibits altered cervical curvature and a decrease in overall joint motion range in the cervical spine.In adolescent with cervical disc herniation,there is a significant increase in stress on the annulus fibrosus,nucleus pulposus,and endplates in the C7-T1 segment.The stress on the left articular cartilage of the C1-2 is notable.Abnormal cervical curvature may be the primary factor causing these stress changes.

BACKGROUND:There is still no consensus on the optimal internal fixation for the treatment of Pauwels Ⅲ femoral neck fracture,and most of the related finite element analyses have been performed using a single simplified loading condition,and the biomechanical properties of commonly used internal fixation devices need to be further investigated. OBJECTIVE:To analyze the biomechanical characteristics of Pauwels Ⅲ femoral neck fractures treated with cannulated compression screw,dynamic hip screw,and femoral neck system by finite element method under different loading conditions of single-leg standing loads and sideways fall loads. METHODS:The DICOM data of healthy adult femur were obtained by CT scanning,imported into Mimics 15.0 software to obtain the rough model of bone tissue.The data exported from Mimics were optimized by Geomagics software,and then three internal fixation models were built and assembled with the femur model according to the parameters of the clinical application of the cannulated compression screw,dynamic hip screw,and femoral neck system by using Pro/E software.Finally,the three internal fixation models were imported into Ansys software for loading and calculation to analyze the stress distribution and displacement of the femur and the internal fixation under different working conditions of single-leg standing loads and sideways fall loads,as well as the stress characteristics of the calcar femorale and Ward's triangle. RESULTS AND CONCLUSION:(1)Under the single-leg standing load and the sideways fall load,the proximal femoral stress of the three internal fixation models was mainly distributed above the fracture end of the femoral neck.The peak stress of the proximal femoral end,fracture end,Ward triangle,and calcar femorale of the three internal fixation models were the smallest in the femoral neck system model and the largest in the cannulated compression screw model.(2)Under the single-leg standing load and the sideways fall load,the peak displacement of the proximal femur of the three internal fixation models was all located at the top of the femoral head,and the peak displacement was the smallest in the femoral neck system model and the largest in the cannulated compression screw model.(3)The peak displacement of the three internal fixation models was all located at the top of the internal fixation device under the single-leg standing and sideways fall loading conditions,and the peak displacement values were the smallest in the femoral neck system internal fixation model and the largest in the cannulated compression screw internal fixation model.(4)The internal fixation stress of the three internal fixation models was mainly distributed in the area near the fracture end of the internal fixation device under the single-leg standing and sideways fall loads,and the peak value of internal fixation stress was the smallest in the femoral neck system model and the largest in the cannulated compression screw model.(5)These results suggest that the mechanical stability of the femoral neck system is the best,but there may be a risk of stress shielding of the fracture end and calcar femorale.The stress of the internal fixation device of the femoral neck system is more dispersed,and the risk of internal fixation break is lower.

BACKGROUND:The reasonable implantation range of femoral prosthesis in unicompartmental knee arthroplasty in patients with osteoporosis has not been investigated,and previous studies have often been based on unicompartmental knee arthroplasty models in normal bone,with fewer mechanical studies in models with non-normal bone.Complications after unicompartmental knee arthroplasty have been shown to be highly associated with osteoporosis. OBJECTIVE:To analyze the biomechanical effects of the coronal inclination of the Sled fixed platform femoral prosthesis on unicompartmental knee arthroplasty in patients with osteoporosis and to find the correlation between osteoporosis and mid-and long-term complications after unicompartmental knee arthroplasty. METHODS:Based on the digital imaging technology to obtain the data of the knee joint and prosthesis,a normal bone knee model is then created by using specialized software such as Mimics and Geomagic studio.Based on a validated normal bone knee model,an osteoporotic knee model was created by changing the material parameters.Totally 14 unicompartmental knee arthroplasty finite element models were created using Sled fixed platform femoral prosthesis:standard position(0°),varus and valgus angles:3°,6°,9° in the normal bone and osteoporosis groups.Stress changes on the surface of polyethylene liner,cancellous bone under tibial prosthesis,and cortical bone were calculated and analyzed in all unicompartmental knee arthroplasty models. RESULTS AND CONCLUSION:(1)In the osteoporotic models,the high stress values of the polyethylene liner surface and the cancellous bone under the tibial prosthesis increased with the increase of the tilt angle of the femoral prosthesis,and the high stress values of the cortical bone surface under the tibial prosthesis increased with the increase of the prosthesis valgus angles and decreased with the increase of the varus angles.(2)For the polyethylene liner surface as well as the subcortical bone surface of the tibial prosthesis,the high stress values of the models for each inclination angle in the osteoporosis group were greater than those of the corresponding models in the normal bone group.For the surface of the cancellous bone under the tibial prosthesis,the high stress values of the tilt angle models of the osteoporosis groups were smaller than those of the normal bone groups.(3)Osteoporosis may cause biomechanical abnormalities in the internal structures of the knee after unicondylar replacement,increasing the potential risk of postoperative aseptic loosening of the prosthesis and periprosthetic fractures.Varus and valgus of the femoral prosthesis in the coronal plane should be avoided as much as possible when performing medial unicompartmental knee arthroplasty with a Sled fixation platform in osteoporotic knees.

BACKGROUND:The biomechanical analysis of scoliosis cases is limited,with only independent analysis focusing on the spine or lower limbs,thus lacking a comprehensive evaluation of the multidimensional body.As a result,it becomes challenging to reflect the movement relationship between the trunk and lower limbs during daily activities,which hinders comprehensive clinical treatment guidance. OBJECTIVE:To explore the relationship between different segments of the spine and the kinematics/kinetics of the lower limbs during gait activities by measuring spinal kinematics in scoliosis patients,to provide a comprehensive and multi-level assessment of the biomechanical differences between scoliosis patients and the normal population,consequently offering evidence-based guidance for the prevention and treatment of scoliosis. METHODS:A cross-sectional study was conducted from July 2020 to June 2021 at the Rehabilitation Hospital Affiliated to Fujian University of Traditional Chinese Medicine in Fuzhou University City.A total of 28 scoliosis patients and 28 normal individuals in the same age group were included.Three-dimensional motion capture system was used to capture gait kinematic data at a sampling frequency of 100 Hz.Two force plates(AMTI 400600,sampling frequency 1 500 Hz)were embedded in a 10-meter-long 2.4-meter-wide level ground walkway(with an effective data collection length of 4 m)to collect kinetic data.The differences in spatial-temporal parameters,kinematics,and kinetics of gait between the two groups were compared.Immediately after inclusion,all subjects underwent full spinal X-ray measurements to compare the differences between the scoliosis and normal groups. RESULTS AND CONCLUSION:(1)Patients with scoliosis exhibited reduced relative rotational range of motion between the shoulder and trunk,as well as between the thorax and pelvis,compared to the normal group(P<0.05).However,the rotational range of motion in the pelvis was larger in patients with scoliosis compared to the normal group(P<0.05).(2)Patients with scoliosis showed decreased range of motion in the hip and knee joints,as well as reduced peak torque in hip joint flexion and extension,and lower peak values of ground reaction forces in the concave and convex directions,in comparison to the normal group(P<0.05).(3)Patients with scoliosis demonstrated greater asymmetry indices in knee joint range of motion,relative rotational range of motion between the shoulder and trunk,and between the thorax and pelvis,when compared to the normal group(P<0.05).(4)These findings illustrate a rigid movement pattern among the shoulder,thorax,and pelvis in patients with scoliosis during level walking.There is a reduction in range of motion in the hip and knee joints,as well as decreased peak torque values in hip joint flexion and extension,and ground reaction forces in the concave and convex directions.These characteristics can serve as foundational elements for assessing rehabilitation and developing treatment plans.

BACKGROUND:As the end bearing joint of the human body,the ankle joint bears the top-down pressure of the body,which leads to the ankle joint is easy to be damaged in the movement,can induce functional ankle instability,which negatively affects daily life.The study of lower extremity biomechanics in patients with functional ankle instability during counter movement jump is of great significance for scientific training,prevention of ankle injury,and clinical rehabilitation after injury. OBJECTIVE:To investigate the kinetics and kinematics of lower limbs in the longitudinal jumping of functional ankle instability population. METHODS:From March to September 2023,15 male patients with functional ankle instability and 15 healthy people,aged 22-28 years old,were recruited in Soochow University.All subjects completed counter movement jump experiment.Vicon infrared high-speed motion capture system and Kistler three-dimensional force measuring table were used to simultaneously collect the lower limb kinematics and kinetics indexes of the two groups of subjects at the take-off stage of counter movement jump,the instant off the ground,the initial landing moment and the peak moment of vertical ground reaction force. RESULTS AND CONCLUSION:(1)At the instant off the ground,the affected side of the functional ankle instability group showed smaller knee internal rotation moment(P=0.020)and smaller ankle internal rotation moment(P=0.009)compared with the affected side of the healthy control group.(2)At the moment of landing,the affected side of the functional ankle instability group showed a smaller hip flexion angle than the affected side of the healthy control group(P=0.039).Compared with the healthy control group,functional ankle instability group showed smaller hip abduction angle(P=0.022),smaller knee varus angle(P=0.010),larger knee external rotation angle(P=0.021),smaller ankle varus angle(P=0.004),and smaller external ankle rotation angle(P=0.008).(3)At the peak of vertical ground reaction force,functional ankle instability group showed a smaller ankle varus angle than healthy control group(P=0.044).(4)The results showed that the lower limb biomechanical characteristics of the patients with functional ankle instability were abnormal compared with the healthy people during counter movement jump,which mainly showed the changes of the kinematics and kinetics indexes of the lower limb joints in the sagittal plane and the frontal plane at the moment of lift-off and landing.These changes reflect that people with functional ankle instability adopt rigid take-off and landing patterns when performing counter movement jump,tend to transfer the load of the affected ankle joint to other joints of the lower limb,and show compensatory phenomenon of the healthy lower limb.Therefore,detection and correction of abnormal biomechanical features should be a part of rehabilitation training for those with functional ankle instability.

BACKGROUND:Fixed-point rotation manipulation of cervical spine is a mechanical operation with high technical requirements,but the biomechanics of fixed-point manipulation of cervical spine still lacks relevant quantitative data.Moreover,the research on the influencing factors of cervical fixed-point rotation manipulation includes many parameters and there are differences,so it is necessary to further analyze its influencing factors to improve its related data. OBJECTIVE:To quantify the biomechanical parameters of cervical spine fixed-point rotation manipulation,explore the correlation between different biomechanical parameters,and the influence of individual characteristics of the subjects on the biomechanical parameters of cervical spine fixed-point rotation manipulation. METHODS:Totally 35 cases of cervical spondylosis were Outpatients from Orthopedic Department of Renai Branch of the First Affiliated Hospital of Guangxi University of Chinese Medicine and selected as the subjects investigated.Wearable mechanical measuring gloves were used to collect biomechanical parameters of cervical spine fixed-point rotation manipulation,including:thumb preload,thumb maximum thrust,palm preload,palm wrench force,and palm wrench maximum force.Personal characteristic parameters were collected,including age,height,weight,and neck circumference.The key biomechanical parameters in the process of cervical spine fixed-point rotation manipulation were analyzed and different individual characteristics were quantified.The results of biomechanical parameters were analyzed using Spearman correlation analysis.The possible effects of different individual characteristic parameters on biomechanics were analyzed. RESULTS AND CONCLUSION:(1)Compared with bilateral mechanical parameters,there was no significant difference between left manipulation and right manipulation(P>0.05).(2)The average of thumb preload force was(7.21±1.19)N;the average of thumb maximum thrust was(28.40±4.48)N;the average of palm preload was(5.67±2.49)N;the average of palm wrench force was(10.90±5.11)N,and the average of palm wrench maximum force was(16.00±7.27)N.(3)There was a significant positive correlation between palm preload and palm wrench force(Rs=0.812,P<0.01).There was a significant positive correlation between palm preload and palm wrench maximum force(Rs=0.773,P<0.01).There was a significant positive correlation between palm wrench force and palm wrench maximum force(Rs=0.939,P<0.01).(4)The weight was positively correlated with thumb preload,palm preload,palm wrench force and palm wrench maximum force(P<0.05).(5)These findings confirm that there is a certain biomechanical standard value in the operation of cervical spine fixed-point rotation manipulation to treat cervical spondylosis.There is no significant difference between the left and right manipulations,which indicates that the manipulation has good consistency and repeatability.There is consistency and coordination among palm preload force,palm wrench force,and palm wrench maximum force.Their contributions to the therapeutic effect are similar.Body weight is an important factor affecting cervical spine fixed-point rotation manipulation.

BACKGROUND:The development of artificial intelligence in the medical field is rapidly advancing,with increasing research on its applications in the field of bone trauma.Through bibliometric analysis,this paper analyzed the research hotspots of artificial intelligence in the field of bone trauma in recent years,and predicted the future research trend. OBJECTIVE:To summarize the development history,research status,hot spots,and future development trends of artificial intelligence technology in the field of bone trauma to provide new insights for future research. METHODS:This study selected relevant literature from the Web of Science core database,covering the period from the inception to August 2023,and retrieved 420 articles related to the application of artificial intelligence,machine learning,and deep learning in the field of bone trauma.After manual screening,202 articles related to this article were exported,and Citespace software was used for visual analysis of cooperation of countries,institutions,cited journals,citation analysis,keyword co-occurrence,and other aspects. RESULTS AND CONCLUSION:(1)The overall number of publications from the 202 selected articles showed an upward trend,indicating significant research potential for future studies.The country with the highest centrality and the highest publication volume was the United States.The University of California(USA)was the most prolific research institution.(2)The top five most commonly used keywords in bone trauma research using artificial intelligence were deep learning,artificial intelligence,bone density,machine learning,and diagnosis.The keyword with the highest centrality was bone density,and the keyword with the highest frequency was deep learning.(3)The top 10 most cited reference papers provided comprehensive insights into the feasibility of applying artificial intelligence techniques to the diagnosis of bone trauma from various perspectives.Among them,eight papers focused on bone and joint injuries and deep convolutional neural networks.One paper discussed the use of deep learning in detecting osteoporosis in CT scans to prevent fragility fractures,while another paper explored the correlation between the application of artificial intelligence in identifying changes in skin texture and the recognition of bone characteristics.(4)In the future,the research hotspots of artificial intelligence will mainly focus on the specific study of fractures caused by bone and joint trauma and osteoporosis.The research trend mainly focuses on improving the performance of artificial intelligence algorithms,using new artificial intelligence technologies to accurately classify and quickly and efficiently diagnose bone injuries,especially for the diagnosis of complex and hidden fractures.By establishing finite element analysis models,more standardized evaluations of bone injuries can be achieved.