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BACKGROUND: Sarcopenia is a progressive, generalized skeletal muscle disease that is closely related to the occurrence of osteoarthritis, fractures, limb disability and death in the elderly. Establishing animal models of sarcopenia is essential to understand the pathophysiology of sarcopenia and to identify effective treatment strategies. OBJECTIVE: To review the evaluation criteria of mouse models of sarcopenia and the modeling methods of mouse models of sarcopenia, and to analyze and compare the advantages and disadvantages of various modeling methods, in order to provide reference for the research and diagnosis and treatment of sarcopenia. METHODS: “Sarcopenia, skeletal muscle aging, mouse model, animal model” in Chinese and English were used as Chinese and English search terms, respectively. The search formula was “(sarcopenia OR skeletal muscle aging) AND (mouse model OR animal model).” CNKI, WanFang and PubMed were searched for related articles published from January 2010 and October 2022. A total of 59 articles were finally included for analysis. RESULTS AND CONCLUSION: There is a faster modeling time in SAMP8 mice and the type of muscle atrophy is consistent with that of patients with sarcopenia. Therefore, it is an ideal model. Although the surgical method can successfully induce muscle atrophy, it requires precise surgical operation, which is difficult and time-consuming. Hindlimb suspension modeling in mice is similar to that of the elderly and can be regarded as an effective model of senile sarcopenia. Although reagent injection molding is simple to perform, both the dose and number of days of administration of reagents are not clear and need to be further research direction. [ABSTRACT FROM AUTHOR]

BACKGROUND: The use of blood flow restriction training in clinical rehabilitation is becoming more common, in part due to technological advances and increased interest in research and medicine. OBJECTIVE: To explore the global trend and development prospects of clinical rehabilitation-related blood flow restriction training application, identify research gaps, and propose future research directions. METHODS: Web of Science, PubMed, and Elsevier were searched for literature related to clinical rehabilitation using blood flow restriction training published from 2001 to 2022. A total of 515 articles were included for further review. Bibliometrics, exploratory factor analysis and cluster analysis were used to reveal the emerging research fields and topics. RESULTS AND CONCLUSION: First of all, the overall research trend of the number of published articles shows a steady rise. The United States is the main research area in this field, and universities contribute the most to journals. Secondly, a core group of authors, led by Loenneke JP, Abe T and Dankel SJ, has been formed, with less collaboration among highly productive authors. Finally, research on blood flow restriction training focuses on skeletal muscle rehabilitation, cognitive functional activity, and chronic disease rehabilitation in clinical rehabilitation, with particular attention to the application of blood flow restriction in the recovery of symptoms such as muscle atrophy, knee pain, and joint effusion after anterior cruciate reconstruction surgery. Theoretical research on low-pressure blood flow restriction that is effective in relieving musculoskeletal symptoms has been hot in recent years, which can systematically guide the musculoskeletal rehabilitation in clinical practice. In the future, clinicians will extend follow-up periods, register larger and more diverse sample sizes, and use randomization techniques to determine appropriate prescribing indications for rehabilitating patients, ensure clinical safety, and quantitatively analyze and develop rehabilitation protocols with the maximum effect at the minimum effective dose for different clinical populations. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mesenchymal stem cells are multipotent stromal cells isolated from bone marrow, fat, umbilical cord and other tissues. It can differentiate into different cell types and secrete a variety of proteins with therapeutic potential, which has a good application prospect in the repair of muscle tissue. OBJECTIVE: To review the research progress of mesenchymal stem cells in promoting muscle tissue repair and provide a theoretical basis for further clinical application. METHODS: Relevant articles published from inception to 2022 were retrieved from CNKI, VIP, WanFang, PubMed, Embase and Web of Science databases. The keywords were “mesenchymal stem cells, muscle tissue, muscle injury, muscle atrophy, exosomes, scaffolds” in Chinese and English. The literature about mesenchymal stem cell migration promoting muscle fiber proliferation and repair was screened. Finally, 98 articles were included for review and analysis. RESULTS AND CONCLUSION: (1) The related mechanisms of mesenchymal stem cell migration promoting muscle fiber proliferation and repair are complex, mostly by anti-inflammatory, inhibiting interstitial fibrosis, inhibiting the fat formation and other ways to promote muscle fiber proliferation and repair. (2) The related biological scaffolds and cell co-culture based on mesenchymal stem cells can significantly compensate for the low survival rate of mesenchymal stem cells after colonization. (3) At present, mesenchymal stem cell therapy still has apparent limitations. In the future, mesenchymal stem cells combined with other therapies should become the primary development trend. [ABSTRACT FROM AUTHOR]

Objective To establish a PCR-based capillary electrophoresis (PCR/CE) to detect Survival Motor Neuron 1 (SMN1) and Survival Motor Neuron 2 (SMN2) genes and to evaluate its performance. Methods PCR/CE and Multiplex Ligation-dependent Probe Amplification (MLPA) for SMA gene diagnosis were used to blindly test the samples in sync. The performance of PCR/CE was assessed using MLPA results as the standard. Results A total of 336 samples were included in this study, consisting of 50 homozygous deletion types (14.9%), 65 heterozygous deletion types (19.3%), and 221 non-deletion types (65.8%). The results of PCR/CE for detecting SMN1 and SMN2 copy numbers (0, 1, 2, 3, ≥ 4) were in complete agreement with the results of the MLPA. Conclusions PCR/CE for gene testing related to SMA could accurately detect copy numbers of exon 7 and exon 8 of the SMN1 and SMN2 genes (0, 1, 2, 3, ≥ 4). [ABSTRACT FROM AUTHOR]

Diabetic muscular atrophy is a rare disease.There are few cases reported in the literature.Its pathogenesis is multifactorial and lacks clear clinical diagnosis basis.The diagnosis of the disease is mostly based on the clinical diagnosis of known or newly discovered diabetic patients.Because the disease is easy to be confused with other diseases, early diagnosis and treatment is difficult, which can easily lead to unnecessary examination and treatment of patients.This article reviewed the disease characteristics, pathogenesis, disease diagnosis and treatment progress of diabetic muscular atrophy, in order to improve the understanding and diagnosis and treatment of the disease. [ABSTRACT FROM AUTHOR]

Objective To explore the changes of laboratory parameters and safety of nusinersen in the treatment of spinal muscular atrophy(SMA). Methods Retrospective analysis was made on the six SMA patients treated with nusinersen in the Department of Neurology at The First Affiliated Hospital of Xi'an Jiaotong University from December 2021 to December 2022. We summarized the patients' clinical data, including genetic diagnosis results, disease classification, and clinical manifestations. Intrathecal injection of 5 mL/12 mg of nusinersen administered on the 1st, 14th, 28th, and 63rd days, followed by maintenance treatment every 4 months. After each administration, we compared and evaluated the patients' cerebrospinal fluid, blood routine, liver function, kidney function, and coagulation function with baseline values. We regularly followed up the patients and recorded adverse reactions after administration to evaluate medication safety. Results A total of six patients were diagnosed with SMA, including four cases of SMA3 type and two cases of SMA4 type. The deletion of exon 7 of the survival motor neuron gene 1(SMN1)in patients led to changes in motor neuron, most of which were caused by limb weakness; in severe cases, the patients were unable to stand. The baseline abnormal test indicators of patients included the increase of cerebrospinal fluid lactate dehydrogenase(CSF-LDH), the increase of creatine kinase(CK), and the decrease of creatinine(Cr). After four times of treatment, the patients' CSF-WBC, CSF-Glu, CSF-Pro, CSF-LDH, WBC, PLT, RBC, ALT, AST, GGT, BUN, uric acid(UA), INR, aPTT, and D-dimer had no significant difference from the baseline (P>0 05). The patients had no other significant adverse reactions except headaches, dizziness, and back pain after puncture. Conclusion Nusinersen has good safety on SMA patients. [ABSTRACT FROM AUTHOR]

BACKGROUND: Slipped capital femoral epiphysis is a common hip disease affecting children and adolescents, causing hip pain and lameness. The incidence of slipped capital femoral epiphysis varies widely, and the etiology is related to gender, mechanical, endocrine, obesity, and genetic factors. OBJECTIVE: To review the core mechanism of slipped capital femoral epiphysis, to discuss the imaging manifestations and quantitative index evaluation based on the pathophysiological mechanism, the progress of treatment methods and unresolved problems. METHODS: The first author used “slipped epiphysis of femoral head, complications, AVN, FAI, hip chondrolysis, SCFE imaging diagnose, X-ray, CT, MRI” as English search terms, and “slipped epiphysis of femoral head, complications, AVN, FAI, chondrolysis, X-ray, CT, MRI” as Chinese search terms. Relevant articles published in PubMed, Web of Science, Embase, CNKI, and Wanfang databases were searched by computer, and screened and evaluated, summed up, and finally 63 related articles were included for review. RESULTS AND CONCLUSION: (1) The current international mainstream views on the pathogenesis of slipped capital femoral epiphysis tend to be the combined effects of mechanical injury factors, endocrine factors and obesity genetic factors. (2) Imaging methods play an increasingly important role in the diagnosis of slipped capital femoral epiphysis. X-ray and three-dimensional CT are more commonly used in the diagnosis of slipped capital femoral epiphysis. MRI can be used to observe changes in epiphyseal plate edema other than bone changes. (3) Different diagnostic methods and measurement parameters can comprehensively and quantitatively evaluate the condition of slipped capital femoral epiphysis patients from the aspects of bone changes, softening injuries and muscle atrophy. (4) Complications of slipped capital femoral epiphysis include avascular necrosis of the femoral head, femoroacetabular impingement sign, chondrolysis, and degenerative arthritis, resulting in long-term and devastating clinical outcomes. (5) Based on the main pathological mechanism, the treatment methods mainly include surgery, endocrine and rehabilitation, and certain results have been achieved. (6) Clinically, patients with slipped capital femoral epiphysis mostly go to the doctor because of pain and claudication in the affected hip and knee. The imaging manifestations are mainly epiphyseal plate widening and relative displacement of femoral head epiphysis and metaphysis. (7) Therefore, in view of the clinicopathological features and complications of patients with slipped capital femoral epiphysis, doctors need to correctly understand the role of imaging in the auxiliary diagnosis of slipped capital femoral epiphysis, and they need to do a good job in the diagnosis and disease assessment on admission, evaluation of surgical effects, and postoperative follow-up, as well as the prediction of contralateral slipped epiphysis in patients with unilateral slipped capital femoral epiphysis, in order to provide an accurate and objective basis for clinical diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of TRB3 gene knockout on skeletal muscle atrophy and fibrosis in diabetic mice.Methods: Thirty TRB3 knockout(TRB3-/-) mice and 30 C57/BL6J mice were randomly divided into 4 groups, including TRB3 knockout diabetes model group(group A), normal TRB3 knockout control group(group B), normal control group(group C) and diabetes model group(group D). Normal control group mice were fed standard rat feed, and diabetic mice were injected intraperitoneally with low dose of streptozotocin to establish diabetic mice model. The forelimb grip strength test, suspension grid test and muscle function test were performed. Meanwhile, the levels of bone microstructure, anti-type I collagen and anti-type III collagen, atrophy gene MuRF1 and atrophy gene atrophy 1 were determined. Results: The hand grip strength of group A, B and D was significantly lower than that of group C, and the hand grip strength of group D was the lowest(P＜0.05). The inverted hanging time of mice in groups A, B and D was significantly lower than that in group C, and the inverted hanging time of mice in group D was the shortest(P＜0.05). CSA value of muscle function in groups A, B and D was significantly lower than that in group C, and CSA value of muscle function in group D was the lowest(P＜0.05). The bone microstructure indexes BMD, BV/TV, Tb.N and Tb.Th in groups A, B and D were significantly lower than those in group C, and the lowest values were in group D(P＜0.05). The values of Tb.Sp and SMI in group C were significantly higher than those in group C, and the values in group D were the highest(P＜0.05). The levels of anti-type I collagen and anti-type III collagen in groups A, B and D were significantly higher than those in group C, and the levels of anti-type I collagen and anti-type III collagen in group D were the highest(P＜0.05).The levels of atrophy gene MuRF1 and Atrogin-1 in groups A, B and D were significantly higher than those in group C, and the levels of Mu RF1 and Atrogin-1 in group D were the highest(P＜0.05). Conclusion: TRB3 gene knockout significantly reduced skeletal muscle atrophy and fibrosis and increased bone strength in diabetic mice. [ABSTRACT FROM AUTHOR]

Type 2 diabetes mellitus （T2DM） is a prevalent metabolic disorder that can lead to muscle atrophy. The characteristics of T2DM with sarcopenia including a loss of muscle mass, decrease of muscle strength, and function dampened with progress. This debilitating condition decrease the quality of life of patients. Therefore, exploring the pathogenesis of T2DM with sarcopenia is crucial for its prevention and treatment. Recently, it has been found that exosomes（ EXs） are involves in the proliferation and differentiation of skeletal muscle but also mediates the exchange of information between skeletal muscle and other tissue organs. Exercise is also known to be an effective way to regulate blood glucose levels and improve muscle mass and strength. Exercise stimulate the release of EXs and their accompanying microRNA（ miRNA）, which may help to slow down the progression of T2DM with sarcopenia. The purpose of this article is to review the pathogenesis of T2DM with sarcopenia by the potential ways in which exercise-induced EXs miRNA would have beneficial on this condition. This review may provide references for the exercise in preventing and treating T2DM with sarcopenia. [ABSTRACT FROM AUTHOR]

BACKGROUND: With the aging of population, sarcopenia in type 2 diabetes mellitus has gradually emerged in front of people. Increasing physical activity is an important approach to prevent and treat type 2 diabetes mellitus and its related sarcopenia. However, current intervention plan, effect evaluation and mechanism of different physical activities in type 2 diabetes-related sarcopenia are still not detailed. OBJECTIVE: To analyze the intervention program, effect evaluation and mechanism of physical activity in type 2 diabetes-related sarcopenia, thereby providing theoretical basis and practical suggestions for physical activity to improve the disease. METHODS: Search terms included “Diabetes Mellitus; T2DM; Sarcopenia; Muscular Atrophy; Exercise; Training; physical activity” in English and Chinese. PubMed and CNKI were searched for relevant literature published from January 1986 to February 2022, including review papers, research papers and meta-analysis. Finally, 53 literatures were included for the review. RESULTS AND CONCLUSION: Appropriate increase in non-leisure physical activity (daily steps above 5 401 per day) can reduce the probability of sarcopenia and maintain physical exercise function in elderly type 2 diabetes patients. Increasing leisure physical activity can prevent the incidence of sarcopenia in elderly type 2 diabetes patients, and any regular physical exercise can be effective. Resistance exercise is significantly superior to aerobic exercise in the prevention and treatment of type 2 diabetes-related sarcopenia. A resistance exercise of moderate intensity and above (3 times a week, 70%-85% 1RM) can effectively increase muscle mass and strength performance in type 2 diabetes patients with sarcopenia, while aerobic exercise mainly delays skeletal muscle loss. Combining resistance exercise with aerobic exercise, nutritional intervention and health education can increase patient compliance and improve treatment efficacy. Resistance exercise mainly improves protein synthesis by activating IRS-PI3K-Akt, mTORC1, p70S6K and 4EBP1 signaling pathways, and improve muscle mass and functions by stimulating muscle satellite cell proliferation and differentiation. Aerobic exercise mainly delays muscle loss by inhibiting ubiquitin protein ligases Atrogin-1 and MuRF1 and skeletal muscle autophagy. [ABSTRACT FROM AUTHOR]

BACKGROUND: There is no effective treatment for denervated skeletal muscle atrophy with poor prognosis, and moreover, the expression profiles of microRNA in vivo are unclear. OBJECTIVE: To analyze the microRNA expression profiles and the changes of transforming growth factor-β1/Smad3 signaling pathway in denervated skeletal muscle atrophy rats using high-throughput sequencing technology and to explore the role and mechanism of microRNA in skeletal muscle atrophy. METHODS: Twelve Sprague-Dawley rats were randomized into two groups: experimental group and control group. Animal models of denervated muscle atrophy were established using truncation of the sciatic nerve in the experimental group. In the control group, only the sciatic nerve was exposed followed by suturing. The bilateral gastrocnemius muscles were completely removed to calculate the muscle wet weight ratio. Atrophy and fibrosis were observed by hematoxylin-eosin staining and the cross-sectional area of the muscle was determined. Illumina HiSeq 2500 sequencing technology was used to identify the microRNA expression profiles in skeletal muscle tissue. In combination with volcano plot, hierarchical clustering map, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes pathway, differentially expressed genes involved in skeletal muscle metabolism were analyzed. Real-time fluorescent quantitative PCR was used to verify the differential expression of candidate genes in muscle tissue and western blot was used to detect the expression of transforming growth factor-β1 and p-Smad3 proteins. RESULTS AND CONCLUSION: Compared with the control group, the muscle wet weight ratio and cross-sectional area were significantly lower in the experimental group (P < 0.05), and the modeling results were in line with expectations. A total of 1 249 differentially expressed microRNAs were identified in the two groups (P < 0.05; | log2 Fold Change | > 0.0). There were 14 microRNAs with significant differential expression, of which 2 were up-regulated and 12 were down-regulated. The results of biological function and pathway analysis indicated that miR-1247-3p, miR-132-5p, miR-21-3p, miR-363-3p, and miR-451-5p with significant differential expression were significantly enriched in cell proliferation, differentiation, apoptosis and other biological processes as well as transforming growth factor-β signaling pathway. The results of real-time fluorescent quantitative PCR showed that the expression of miR-21-3p in the gastrocnemius muscle tissue of the experimental group was significantly lower (P < 0.001), which was consistent with the trend of the high-throughput sequencing results. Western blot results showed that the protein expression levels of transforming growth factor-β1 and p-Smad3 were significantly higher in the experimental group than the control group (P < 0.05). To conclude, microRNA plays a key role in the physiological and pathological processes of skeletal muscle atrophy. miR-21-3p may play a role in skeletal muscle cell metabolism by activating the biological activity of transforming growth factor-β1/Smad3 signaling pathway. [ABSTRACT FROM AUTHOR]

Objective* To investigate the morphologic and functional changes of the diaphragm of children during early mechanical ventilation under synchronized intermittent mandatory ventilation (SIMV) mode. Methods • Children were admitted to the Pediatric Intensive Care Unit (PICU) of Xinhua Hospital, Shanghai Jiao Tong University School of Medicine and received mechanical ventilation for at least 96 h from October 2020 to December 2021. Bedside ultrasonic testing was conducted to inspect the changes in the diaphragm at three different time points (0, 48, and 96 h, respectively). Kruskal-Wallis H test was conducted for examining the abdominal fat thickness, atrophy rate, diaphragm thickness and DE between the groups. The diaphragm thickness was further compared by Bonferroni's test for ex-post hoc comparisons. Univariate ANOVA was performed for analyzing the diaphragm contraction velocity, diaphragm thickening fraction and diaphragmatic atrophy rate between the groups. Results • Forty-six children in PICU with complete measurement data were included. Their average age was 2.94 (1.35, 7.00) years, including 23 males and 23 females. The main disease leading to perform mechanical ventilation was pneumonia (52.17%). There was no significant difference between the choice of ventilator parameters and oxygenation status during the observation period (P>0.05). In the early stage of mechanical ventilation (within 96 h), 50% of children showed atrophy of abdominal subcutaneous fat, 36.96% showed nutritional disorders (fasting and need parenteral nutrition support), and 93.5% of children received glucocorticoid therapy. However, there was no significant difference in the atrophy degree of abdominal subcutaneous fat between the three time points (all P>0.05). Bedside ultrasonography detected significant atrophy of bilateral diaphragm thickness at three different time points (all P=0.000). After 48 h of mechanical ventilation, the atrophy rate of the right diaphragm was 4.27%±7.36%, and the left diaphragm was 3.88%±6.85%. After 96 h of ventilation, the atrophy rate of the right diaphragm was 7.69%±7.74%, and the atrophy rate of the left diaphragm came to 7.55%±7.69%. The atrophy rate of the bilateral diaphragm was significantly higher in the first 48 h of mechanical ventilation than in the 48 h to 96 h (all P =0.000). However, there were no statistically significant differences in changes of diaphragm function-related indicators (diaphragm excursion, diaphragm contraction velocity, and diaphragm thickening fraction). Conclusion • The bedside ultrasound is a proven tool to detect diaphragmatic atrophy in mechanically ventilated children. Mechanical ventilation can induce structural atrophy of the diaphragm in children during early mechanical ventilation under SIMV mode, which is more pronounced in the first 48 h. However, the early morphological changes of the diaphragm have not affected its function. [ABSTRACT FROM AUTHOR]

BACKGROUND: Peripheral nerve injury is very common in clinic, but its regeneration rate is very slow. During nerve recovery, muscle atrophy has already occurred irreversibly, which seriously affects the quality of life of patients. Therefore, it is particularly important to find an effective method for the treatment of denervated muscle atrophy. OBJECTIVE: To summarize the biological characteristics of exosomes and their mechanisms of involvement in skeletal muscle formation and atrophy, focus on the process of denervated muscle atrophy and the role of exosomes in the treatment of denervated muscle atrophy, providing a new method for the treatment of denervated muscle atrophy. METHODS: Relevant articles were searched on PubMed database with English search words “exosome, skeletal muscle, muscle atrophy, muscle regenerate, peripheral nerve injury, denervation muscle atrophy”. Related articles were searched on Wanfang and CNKI databases, and the Chinese search words were “exosome, skeletal muscle, peripheral nerve injury, muscle atrophy, muscle regeneration, nerve repair, denervated muscle atrophy”, and some articles were searched with literature retrospective method. RESULTS AND CONCLUSION: (1) Exosomes are widely distributed in all kinds of body fluids. They act on recipient cells through paracrine or autocrine and affect the phenotype of recipient cells. (2) The main function of exosomes in muscle may be related to the delivery of RNA. Exosomal miRNAs secreted or ingested by muscle cells are involved in muscle development, growth, adaptation and regeneration. (3) After peripheral nerve injury, muscle loses its motor control and nutritional support, and then apoptosis and proteolysis increase, leading to muscle atrophy. (4) Exosomes from different cell sources repair injured nerves directly or indirectly, thereby alleviating muscle atrophy. It has been preliminarily confirmed that exosomes may also mediate the expression regulation of related regenerative genes in a miRNA-dependent manner to promote neural regeneration. Therefore, exosomes can act on nerve cells and delay denervated muscle atrophy. [ABSTRACT FROM AUTHOR]

BACKGROUND: Treatments for cervical spondylotic amyotrophy are still controversial. For cervical spondylotic amyotrophy patients, conservative treatment can generally stabilize or improve symptoms, but there is no cure. Surgical treatment is recommended for cervical spondylotic amyotrophy with progressive or severe neurological deterioration; however, most clinicians choose surgical methods based on their own clinical experience, and there is no unified standard or industry consensus. The prognosis of different types of cervical spondylotic amyotrophy is significantly different, which may influence the selection of surgical options. OBJECTIVE: To summarize and analyze the pathogenesis, diagnosis, clinical manifestations, types, treatments, and prognosis of cervical spondylotic amyotrophy by reviewing the related researches of cervical spondylotic amyotrophy, in order to provide reference for the selection of clinical treatment and surgical options. METHODS: Articles related to cervical spondylotic amyotrophy published from 1952 to 2020 were retrieved by computer in PubMed, EMbase, Web of Science, CNKI, and WanFang databases. Finally 44 articles that met the inclusion criteria were selected. RESULTS AND CONCLUSION: The clinical manifestations of cervical spondylotic amyotrophy are asymmetry, segmental and other characteristics of upper limb motor weakness accompanied by obvious muscle atrophy, while the lower limbs are not characterized by obvious sensory disturbance or spastic paralysis Clinically, according to the position of muscle atrophy, it is classified into proximal type, distal type and mixed type. This disease needs to be distinguished from motor neuron disease and muscular dystrophy to avoid misdiagnosis and erroneous treatment. The pathogenesis of cervical spondylotic amyotrophy is yet unclear. There are two views on ventral nerve root and spinal anterior horn injury. The latter is recognized by most scholars. The diagnosis of cervical spondylotic amyotrophy is mainly based on clinical symptoms, imaging examinations, and neuroelectrophysiological examinations. Some diseases, such as motor neuron disease, should be excluded in differential diagnosis. Surgical treatment is mainly used for cervical spondylotic amyotrophy. Anterior cervical spine anterior surgery is the first choice, and posterior surgery is preferred for patients with multi-segment cervical posterior longitudinal ligament ossification, anterior decompression impossible or high risk of decompression. Different types of cervical spondylotic amyotrophy patients have different prognostic results after surgery. Prognosis of the proximal type is better than that of the distal type, and prognosis of the mixed type is the worst. Surgery via the anterior cervical approach has better results than that via the posterior cervical approach. [ABSTRACT FROM AUTHOR]

BACKGROUND: Massage vibration therapy has definite effects on peripheral nerve injury. However, less is reported on its mechanism of action. OBJECTIVE: To explore the mechanism of massage vibration on peripheral nerve regeneration after injury. METHODS: Twenty-eight SD rats were randomly divided into sham operation group (n=8) and model group (n=20). Animal models of sciatic nerve injury were established in the model group by sciatic nerve clamping. Four rats in the model group were then randomly selected for model identification, and the remaining rats in the model group were randomly divided into sham intervention group (n=8) and massage vibration method group (n=8). In the sham operation group the skin was opened and sutured with no injury. The rats were intervened on the 7th day after modeling. In the massage vibration group, massage vibration was given using a vibrator by touching the skin of the right lower extremity at a frequency of 8 Hz, once a day, 2 min per time, for 4 consecutive weeks. In the sham intervention group, the vibrator only touched the skin but with no massage treatment. No treatment was given in the sham operation group. Incline plane test and behavioral indexes of sciatic function index were performed and measured after 7, 14, and 28 days of treatment, and muscle satellite cells, insulin-like growth factor 1, and MyoD biochemical index were detected after 28 days of treatment. The study protocol was approved by the Animal Experiment Ethics Committee of Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine. RESULTS AND CONCLUSION: In the inclined plane test, the inclination angle of the sham intervention group and the massage vibration group was significantly smaller than that in the sham operation group after 7, 14, and 28 days of treatment (P < 0.05), but there was no significant difference between the sham intervention group and the massage vibration group (P > 0.05). The sciatic function index value in the massage vibration group was significantly better than that in the sham intervention group after 14 and 28 days of treatment. The positive expression of muscle satellite cells, insulin-like growth factor 1, and MyoD in the massage vibration group was highest after 28 days of treatment, followed by the sham intervention group and sham operation group (P < 0.05). To conclude, massage vibration method can effectively promote the recovery of motor function, accelerate the expression of insulin-like growth factor 1 and MyoD, expedite the proliferation and differentiation of muscle satellite cells, alleviate skeletal muscle atrophy, and accelerate sciatic nerve regeneration after injury. [ABSTRACT FROM AUTHOR]

BACKGROUND: Sarcopenia is defined as a syndrome of progressive reduction in age-related skeletal muscle mass, accompanied by declines in muscle strength and/or function, triggering a series of undesirable consequences such as accidental fractures. OBJECTIVE: To review the progress in the definition, measurement methods, correlation with fractures, prevention and treatment of sarcopenia. METHODS: PubMed and CNKI were searched for literatures related to sarcopenia using the keywords of “sarcopenia/muscular atrophy/muscle/fracture/ treatment/prevention.” Keywords were searched alone and in combination, followed by full-text reading. RESULTS AND CONCLUSION: EWGSOP, IWGS, AWGS and other working groups have developed a standardized definition and diagnosis of sarcopenia. However, the criteria for defining sarcopenia vary slightly in literatures included in PubMed. Risk of fractures is increased in older adults with sarcopenia, and sarcopenia will have a worse effect in patients with osteoporosis. Animal experiments have verified that sarcopenia and osteoporotic fractures coexist in animal models, and sarcopenia can lead to delayed fracture healing. Exercise and nutrition intervention are currently used prevention and treatment programs. Osteocalcin, omega-3 polyunsaturated fatty acids, soluble activin IIB receptor and stem cell transplantation have great potential in the treatment of sarcopenia. [ABSTRACT FROM AUTHOR]

BACKGROUND: Skeletal muscle is the main tissue to maintain human health, and sarcopenia affects people’s health and quality of life. Muscle satellite cells are skeletal muscle stem cells activated to proliferate and differentiate when stimulated by exercise, promote muscle hypertrophy, and delay the occurrence of sarcopenia. OBJECTIVE: To provide exercise prevention and treatment guidance for age-related sarcopenia, muscle atrophy, and muscle injury repair, and provide theoretical support for subsequent research. METHODS: CNKI, PubMed, and Web of Science were searched for relevant documents published from 2010 to 2020 with the keywords of “skeletal muscle, satellite cells, proliferation, differentiation, muscle repair, scrcopenia” in Chinese and English, respectively. After initial screening of titles and abstracts, 100 articles were included for review. RESULTS AND CONCLUSION: There are many studies on the proliferation and differentiation of exercise-activated muscle satellite cells. Compared with endurance exercise (aerobic), resistance exercise has a significant effect. Different types of exercises can activate the proliferation and differentiation of different types of muscle satellite cells. Factors such as exercise intensity, load threshold, exercise time and frequency all influence the degree of satellite cell activation, proliferation and differentiation. Research on the interaction between exercise-activated muscle satellite cell proliferation and differentiation signaling pathways is insufficient, and it is found that exercise can regulate muscle extracellular matrix, oxidative stress levels, and autophagy to improve sarcopenia. How exercise activates the signal pathways of muscle satellite cell proliferation and differentiation to effectively promote synergy requires more in-depth research and exploration. [ABSTRACT FROM AUTHOR]

BACKGROUND: Studies have shown that reduced diameter and number of muscle fibers are related to muscle atrophy, especially type II muscle fibers. OBJECTIVE: To explore the correlation between the distribution characteristics of skeletal muscle fibers and bone mineral density in postmenopausal women with hip fractures. METHODS: The clinical data of 60 female postmenopausal patients undergoing surgical treatment for hip fractures were included. Bone mineral density and muscle content were measured by dual energy X-ray, and the Appendicular Skeletal Muscle Mass Index (ASMI) was calculated. According to the diagnostic criteria for osteoporosis, the included patients were divided into four groups with normal bone mass, reduced bone mass, osteoporosis, and severe osteoporosis, with 15 cases in each group. During operation, the patient’s gluteus medius muscle fibers were taken, and their diameter and distribution characteristics were observed under a microscope after slicing, fixing, and staining. Muscle content and femoral neck bone density at the healthy side were tested. Pearson correlation analysis was used to analyze the correlation between muscle fiber diameter and skeletal muscle content at the affected side and the bone mineral density of the contralateral femoral neck. RESULTS AND CONCLUSION: The body muscle content and trunk muscle content of the severe osteoporosis group were significantly lower than those of the other three groups (P < 0.05), but there was no significant difference between the other three groups (P > 0.05). The muscle content of the limbs in the normal bone mass group was significantly higher than that in the osteoporosis group and severe osteoporosis group (P < 0.05), and the muscle content of the limbs in the reduced bone mass group was higher than that in the severe osteoporosis group (P < 0.05). The ASMI value of the limbs in the severe osteoporosis group was significantly lower than that in the normal bone mass group and reduced bone mass group (P < 0.05). The femoral neck bone mineral density of postmenopausal women with hip fractures had a certain correlation with age, body mass, and type II muscle fiber diameter. The linear fitting R2 of femoral neck bone density with type II muscle fiber diameter and muscle content of the limbs was 0.103 and 0.243, respectively. To conclude, the bone mineral density of female patients with hip fractures is closely related to age, body mass index, muscle content of different body parts (body, limbs, trunk), and ASMI. Type II muscle fiber diameter and muscle content of the limbs have a positive correlation with femoral neck bone mineral density, suggesting that in the prevention of hip fractures in postmenopausal elderly women, we should adopt a comprehensive program of exercise, nutrition and drug treatment to increase bone mass and improve muscle quality. [ABSTRACT FROM AUTHOR]

BACKGROUND: Previous studies have shown that neurotrophin 3 (NT3)-chitosan can induce endogenous neurogenesis and axon regeneration in rats with spinal cord injury, and promote recovery of motor and sensory functions in rats. OBJECTIVE: To observe the effect of rehabilitation training combined with NT3-chitosan biomaterial scaffold on skeletal muscle morphological changes and functional recovery in rats with complete spinal cord injury. METHODS: Fifty adult female Wistar rats were randomly divided into five groups, 10 in each group. The sham group was not modeled; the remaining four groups were prepared with T7-T8 complete 5-mm spinal cord injury model, and the lesion control was not performed any intervention after modeling. The other three groups were given rehabilitation training, NT3-chitosan active biomaterial scaffold, NT3- chitosan active biomaterial scaffold combined with rehabilitation training intervention. Rehabilitation training started 2 weeks after modeling. Before operation, 2, 4, 6, 8, 10, and 12 weeks after operation, all of rats were subjected to double-blind open-field BBB scores. After 12 weeks, the skeletal muscles of the hind limbs (tibialis anterior muscle, gastrocnemius muscle, and soleus muscle) were taken for hematoxylin-eosin staining and acetylcholinesterase staining. The changes in muscle atrophy and motor endplates were assessed in each group. The experimental plan was approved by the Animal Experiment Committee of Capital Medical University (approval No. AEEI2018-105). RESULTS AND CONCLUSION: (1) The BBB score at each time point in the sham group was higher than that in the other four groups (P < 0.05); and the scores at 8, 10, and 12 weeks after the NT3-chitosan combined rehabilitation training group were higher than the lesion control group, the lesion control combined rehabilitation training group, and NT3-chitosan group (P < 0.05). (2) At 12 weeks after operation, hematoxylin-eosin staining showed that the cross-sectional area and diameter of muscle fibers of each skeletal muscle were smaller in the other four groups than that in the sham group (P < 0.05). The cross-sectional area and diameter of muscle fibers of each skeletal muscle in the NT3-chitosan combined rehabilitation training group were higher than the lesion control group, the lesion control combined rehabilitation training group, and NT3-chitosan group (P < 0.05). (3) At 12 weeks after operation, the acetylcholinesterase staining showed that the average optical density of the acetylcholinesterase on motor endplate of the muscle was lower in the other four groups than that in the sham group (P < 0.05); the average optical density of the acetylcholinesterase of the motor endplate in the NT3-chitosan combined rehabilitation training was significantly higher than that in the lesion control, lesion control combined rehabilitation training, and NT3-chitosan groups (P < 0.05). (4) The results show that NT3-chitosan combined with rehabilitation training can effectively prevent muscular atrophy of hind limb skeletal muscles in rats with complete spinal cord injury, improve the average optical density of the acetylcholinesterase of the motor endplate, reduce neuromuscular joint degeneration, and improve rat hindlimb motor function. [ABSTRACT FROM AUTHOR]

BACKGROUND: The regulation of mitochondrial energy metabolism by adenylate activated protein kinase (AMPK) is an important cause of fat accumulation in obese and type 2 diabetic patients. Chronic inflammation will further induce skeletal muscle atrophy. Aerobic exercise can increase the activity of AMPK and regulate energy metabolism, but the mechanism of aerobic exercise in improving skeletal muscle atrophy in type 2 diabetes by increasing AMPK is unclear. OBJECTIVE: To explore the effect of aerobic exercise on skeletal muscle atrophy in type 2 diabetic rats and the role of AMPK. METHODS: The model of type 2 diabetic rats was established by high fat feeding and streptozotocin injection, and the rats were divided into four groups: control group (n=6), exercise group (n=9), diabetic control group (n=8) and diabetic exercise group (n=12). The control group and the diabetic control group were kept for 4 weeks, and the exercise group and the diabetic exercise group were given aerobic exercise intervention for 4 weeks. After 4 weeks of aerobicexercise (running speed 16 m/min, 60 min/d, 5 days/week), the muscle atrophy of soleus was observed by immunohislochemicsl staining. The expression levels of AMPK, PGC-1α, MAFbx and MuRF1 were detected by western blot assay. The study protocol was approved by the Ethical Committee of School of Sport Science, Beijing Sport University in China on June 25, 2016, with approval No. 2016014. RESULTS AND CONCLUSION: Blood glucose of type 2 diabetes rats was significantly increased, and body weight and insulin levels of type 2 diabetes rats were significantly decreased (P < 0.01). The mean cross sectional area of sole us fiber in the diabetic group was significantly lower than that in the control group (P < 0.01), and the cross sectional area of soleus muscle fiber in the diabetic exercise group was significantly higher than that in the diabetic group (P < 0.01). The expression levels of AMPK and PGC-1α in the soleus muscle of diabetic rats were significantly lower than those in the control group, and the expression levels of MAFbx and MuRF1 were significantly higher than those in the control group (P < 0.01). The expression levels of AMPK, MAFbx and Mu RF! in the diabetic exercise group were significantly higher than those in the diabetic group (P < 0.01). These results suggest that aerobic exercise can improve milochondrial function, inhibit the expression of MAFbx and MuRF1, improve skeletal muscle atrophy and restore the metabolic balance of type 2 diabetes mellitus to some extent by activating AMPK/PGC-1α signaling pathway. [ABSTRACT FROM AUTHOR]

BACKGROUND: There are a large number of patients with brachial plexus injury in clinical practice, and surgical methods are various. The concerning reviews are few.OBJECTIVE: To review the anatomy, surgical methods and surgical history of brachial plexus injury, so as to provide clinical guidance for orthopedic surgeons.METHODS: The first author searched relevant articles in PubMed and CNKI databases from January 1972 to October 2018. The keywords were "brachial plexus, injury, diagnosis, treatment, classification" in English and Chinese, respectively. A total of 478 related articles were retrieved, and 73 articles were eligible for the inclusion criteria.RESULTS AND CONCLUSION:(1) Through the continuous basic researches and clinical practice of domestic and foreign scholars and doctors, the surgical treatment of brachial plexus injury surgery gradually becomes rich and mature, and has achieved great progress.(2)Great progress has been made in the treatment of brachial plexus injury. Due to the complexity of mechanism and anatomical structure of brachial plexus injury, there are still many problems. Although the changes after nerve injury have been described in terms of morphology,electrophysiology and histochemical changes, the essence of muscular atrophy has not been elucidated. The ultimate goal of brachial plexus injury treatment is to reconstruct the internal muscle of the hand, which determines the recovery effect of hand function.(3) Brachial plexus injury is still a worldwide problem in the field of medicine, and is an issue of concern. There are various methods, which have achieved good clinical outcomes, but the irreversible muscle atrophy is difficult to avoid.(4) How to accurately diagnose brachial plexus injury, improve and innovate the nerve displacement method, accelerate the nerve regeneration, and restore hand muscle function is the research focus and direction in the field of hand surgery. A further exploration is needed to provide foundation for further research and clinical practice. [ABSTRACT FROM AUTHOR]

Objective:By conducting screening studies on the deletion mutations in exon 7 and exon 8 (E7, E8) of SMN1 gene in pregnant women, an accurate, rapid, simple, and high-throughput prenatal screening and diagnosis of this gene locus was established. SMA patients can be prevented. Methods:QF-PCR was used to screen the deletion of SMN1 gene E7 and E8 in 162 cases of women in mid-pregnancy. When the spouses were carriers of SMA pathogenic genes, fetal DNA was extracted to detect SMN1 gene deletion. The high-risk fetal MLPA genetic diagnosis was performed at the same time. Results:A total of 162 pregnant women were screened and the presence of SMN1 E7 heterozygous carriers were found in 6 cases. As for the QF -PCR test results of the carriers' spouses,4 cases showed that E7 and E8 were all normal and 2 cases showed loss of heterogeneity. As to the two high-risk fetus whose both parents were SMA carriers,amniotic fluid DNA testing suggested that 1 fetus had E7 and E8 homozygous deletion, and the other one showed loss of heterogeneity. The results of MLPA were same with QF -PCR. Conclusions:QF-PCR can be used in the screening and diagnosis of SMA patients in large pregnant population. It has great clinical value to prevent the birth of SMA children. [ABSTRACT FROM AUTHOR]

Skeletal muscles are the body′s agent of motion and important sites for the control of metabolism. The respiratory muscles are unique among skeletal muscles, since they must work without sustained rest throughout life. The diaphragm is the principal inspiratory pump muscle,it is more resistant to developing fatigue than limb muscles. The blood flow and the oxidative capacity of the diaphragm exceed those of limb muscles. Muscle atrophy and contractile dysfunction can be found in a variety of diseases. The reductions in muscle mass is tilted toward reduced protein synthesis and enhanced protein degradation. During pathologic conditions, enhanced protein breakdown is the main reason resulting in myofiber atrophy. Recent studies have underlined a critical role for the autophagy-lysosome (AL) system in regulating muscle mass. The main function of AL system involves the delivery of cytoplasmic cargo sequestered inside double-membrane vesicles to the lysosome which can eliminate the cell of superfluous or damaged organelles and proteins. Basal autophagy is necessary to muscle homeostasis, since it is responsible for the removal of intracellular metabolites. But excessive activation of autophagy can aggravate catabolism and contribute to muscle loss. This review focuses on the AL system and discusses its beneficial or detrimental role in skeletal and diaphragm atrophy. [ABSTRACT FROM AUTHOR]

Objective To investigate the MRI manifestation of Hirayama disease. Methods Cervical spine MRI of 11 patients with clinically suspected Hirayama disease was retrospectively analyzed. The MRI examinations were performed in neutral position and flexion without and with intravenous contrast. Results In the neutral position, MRI showed straightening of the cervical spine, thinning and asymmetric flattening of the lower cervical cord in all patients as well as cervical intervertebral disc bulge in 6 patients. In neck flexion, the lower cervical cord thinning was more pronounced with anterior shift of the cord and dura mater as well as heterogeneous T1 isointensity and T2 hyperintensity in the widened posterior epidural space including small signal voids in 9 patients..The widened posterior epidural space enhanced in flexion. Conclusion MRI characteristic in neck flexion is diagnostic for Hirayama disease. [ABSTRACT FROM AUTHOR]

Objective To investigate the relationship between beta enolase gene two point rs121918403 (G/A), rs121918404 (G/A) polymorphism with skeletal muscle Atrophy in the patient with chronic obstructive pulmonary disease (COPD). Method Beta enolase genes were assayed by polymerase chain and one-way directed sequencing methods between 120 COPD patients and 60 age-matched controls in Kunming. Result There was no mutation in rs121918403 (G/A) and rs121918404 (G/A) of beta enolase gene in COPD patients and healthy subjects. Conclusion SNPs of two mutational sites of beta enolase are not correlated to skeletal muscle atrophy in COPD patients in Kunming. [ABSTRACT FROM AUTHOR]

Objective To investigate the feasibility of DNA sequencing analysis in molecular diagnosis for spinal muscular atrophy (SMA). Methods Two pairs of primers were utilized to amplify the region including 5 different bases in SMA-causative gene SMN1 and its homologue copy SMN2 by polymerase chain reaction (PCR). The first primer amplified a fragment 501 bp long spanning from SMN intron 6 to intron 7 targeting four different bases (g.31957, 32006, 32154 and 32269). The second primer reversely amplified a 189 bp long fragment within SMN exon 8 including one base-pair difference (g.32734). PCR procedure was followed by Sanger sequencing technique to identify the 5 different bases. SMA patients caused by SMN1 homozygous deletion were distinguished from carriers or normal controls by absence of SMN1 specific bases in sequence chromatograms. This assay was performed in 7 SMA suspected patients and their parents. The specimens were also detected by PCR- restriction fragment length polymorphism (RFLP) method. Results It was found that 6 of 7 SMA suspected patients showed only SMN2 specific bases at the 5 different base positions among the region from intron 6 to exon 8, which meant the patient displaying only SMN2-specific nucleotide a, T, g, g and A at g.31957, 32006, 32154, 32269 and 32734, while their parents (carriers) showed a/g, T/C, g/a, g/a and A/G at the same sites. SMN1 gene was deleted in the patient, and the deletion region was inferred from intron 6 to exon 8. Because carriers had both SMN1 and SMN2 genes, they can be discriminated from the SMN1 deleted patient. One of 7 patients yield an unique sequence chromatogram of a, T, g, g and A/G, indicating that exon 8 of SMN1 was not deleted in this patient. Conclusion DNA sequencing analysis is an alternative simple method for detecting SMA caused by homozygous deletion of SMN1. We recommend to replace the widely used PCR-RFLP method with DNA sequencing assay. [ABSTRACT FROM AUTHOR]