OBJECTIVE: To assess the impacts of electroacupuncture (EA) on the gait, oxidative stress, inflammatory reaction, and protein degradation in the rats of denervated skeletal muscle atrophy, and explore the potential mechanism of EA for alleviating denervated skeletal muscle atrophy. METHODS: Forty male SD rats, 8 weeks old, were randomly assigned to a sham-surgery group, a model group, an EA group, and a p38 MAPK inhibitor group, with 10 rats in each group. The right sciatic nerve was transected to establish a rat model of denervated skeletal muscle atrophy in the model group, the EA group and the p38 MAPK inhibitor group. In the sham-surgery group, the nerve was exposed without transection. One day after successful modeling, the rats in the EA group received EA at "Huantiao" (GB30) and "Zusanli" (ST36) on the right side, using a continuous wave with a frequency of 2 Hz and current intensity of 1 mA, for 15 min in each session, EA was delivered once a day, 6 times a week. In the p38 MAPK inhibitor group, the rats received the intraperitoneal injection with SB203580 (5 mg/kg), once a day, 6 times a week. The intervention was composed of 3 weeks in each group. After the intervention completion, the CatWalk XT 10.6 animal gait analysis system was used to record the gait parameters of rats. The wet weight ratio of the gastrocnemius muscle was calculated after the sample collected. Using HE staining, the fiber morphology and cross-sectional area of the gastrocnemius muscle were observed; ELISA was employed to measure the content of interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α in the gastrocnemius muscle; the biochemical hydroxyamine method was adopted to detect the content of superoxide dismutase (SOD) and malondialdehyde (MDA) in the gastrocnemius muscle; with immunohistochemistry and Western blot used, the expression of p38 mitogen-activated protein kinase (p38 MAPK), phosphorylated (p)-p38 MAPK, muscle atrophy F-box gene (Atrogin-1), muscle RING finger 1 (Murf-1), nuclear factor E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) was detected in the gastrocnemius muscle. RESULTS: Compared to the sham-surgery group, in the model group, the standing duration, the swing time and the step cycle were increased (P<0.001), the footprint area of the maximum contact time, the print area, the average intensity of the maximum contact time, the average intensity, the swing speed, and the step length were decreased (P<0.001); the wet weight ratio of gastrocnemius muscle and fiber cross-sectional area were reduced (P<0.001); the content of IL-6, IL-1β, TNF-α and MDA in gastrocnemius muscle elevated (P<0.001), and that of SOD reduced (P<0.001); the positive and protein expression of p-p38 MAPK, Atrogin-1 and Murf-1 elevated (P<0.001) and that of Nrf2 and HO-1 dropped (P<0.001). When compared with the model group, in the EA group and the p38 MAPK inhibitor group, the standing duration, the swing time and the step cycle decreased (P<0.01), the footprint area of the maximum contact time, the print area, the average intensity of the maximum contact time, the average intensity, the swing speed, and the step length increased (P<0.01); the wet weight ratio of gastrocnemius muscle and fiber cross-sectional area were improved (P<0.01, P<0.05); the content of IL-6, IL-1β, TNF-α and MDA in gastrocnemius muscle dropped (P<0.05, P<0.01), and that of SOD elevated (P<0.01, P<0.05); the positive and protein expression of p-p38 MAPK, Atrogin-1 and Murf-1 dropped (P<0.01, P<0.05) and that of Nrf2 and HO-1 increased (P<0.01, P<0.05). CONCLUSION Electroacupuncture may alleviate skeletal muscle atrophy in denervated skeletal muscle atrophy rats by mediating the p38 MAPK activity, thereby suppressing oxidative stress, inflammatory reaction, and protein degradation.
Animals ; Electroacupuncture ; Male ; Rats ; p38 Mitogen-Activated Protein Kinases/genetics* ; Rats, Sprague-Dawley ; Muscular Atrophy/metabolism* ; Muscle, Skeletal/metabolism* ; Humans ; Signal Transduction ; Superoxide Dismutase/genetics* ; Tumor Necrosis Factor-alpha/genetics* ; Oxidative Stress ; MAP Kinase Signaling System ; Acupuncture Points

This study aims to explore the role and mechanism of CXC chemokine receptor 3 (CXCR3) in cisplatin-induced skeletal muscle atrophy. Wild-type mice were divided into two groups: cisplatin group and control group (treated by normal saline). The results showed that, compared to the control group, the expression levels of CXCR3 mRNA and protein were significantly up-regulated in the skeletal muscle of the cisplatin group, suggesting that CXCR3 may play an important role in the model of cisplatin-induced skeletal muscle atrophy. To further investigate its role and potential mechanisms, CXCR3 knockout mice and wild-type mice were treated with cisplatin to induce skeletal muscle atrophy. The results revealed that CXCR3 knockout not only failed to alleviate cisplatin-induced skeletal muscle atrophy, but also further reduced body weight, skeletal muscle mass, and muscle fiber cross-sectional area. Further analysis showed that, in the cisplatin-induced muscle atrophy model, CXCR3 knockout significantly up-regulated the expression levels of E3 ubiquitin ligases in skeletal muscle and down-regulated the expression levels of myogenic regulatory factors. To explore the molecular mechanism by which CXCR3 gene deletion exacerbated cisplatin-induced skeletal muscle atrophy, transcriptomic sequencing was performed on the atrophied skeletal muscles of wild-type and CXCR3 knockout mice. The results showed that, compared to wild-type mice, 14 genes were significantly up-regulated and 12 genes were significantly down-regulated in the skeletal muscle of CXCR3 knockout mice. Gene set enrichment analysis (GSEA) revealed a significant enrichment of genes related to fatty acid β-oxidation. Quantitative real-time PCR validation results were consistent with the transcriptomic sequencing results. These findings suggest that CXCR3 may counteract cisplatin-induced skeletal muscle atrophy by up-regulating E3 ubiquitin ligases, down-regulating myogenic regulatory factors, and enhancing the recruitment of fatty acid β-oxidation-related genes.
Animals ; Cisplatin/adverse effects* ; Muscular Atrophy/physiopathology* ; Mice ; Receptors, CXCR3/metabolism* ; Ubiquitin-Protein Ligases/metabolism* ; Mice, Knockout ; Oxidation-Reduction ; Fatty Acids/metabolism* ; Muscle, Skeletal/metabolism* ; Mice, Inbred C57BL ; Male

Skeletal muscle atrophy is characterized by a reduction in both the size and quantity of skeletal muscle fibers, resulting in impaired muscle strength and function. It mainly includes disuse muscle atrophy, aging muscle atrophy, denervated muscle atrophy and muscle atrophy caused by disease etc. As a cost-effective way, exercise has been widely used in the prevention and treatment of skeletal muscle atrophy, but its mechanism for improving skeletal muscle atrophy remains unclear. Recent studies have indicated that insulin-like growth factor 1 (IGF-1) plays an important role in improving muscle atrophy through exercise, in addition to promoting the survival of neurons, lowering blood sugar, and anti-inflammation. This article reviews recent findings on the mechanisms by which IGF-1 mediates exercise-induced improvement in skeletal muscle atrophy, providing a theoretical basis for the prevention and treatment of this disease.
Insulin-Like Growth Factor I/physiology* ; Muscular Atrophy/therapy* ; Humans ; Exercise/physiology* ; Muscle, Skeletal ; Animals ; Insulin-Like Peptides

OBJECTIVE: To compare the effects of piriformis muscle release versus preservation in total hip arthroplasty (THA) via supercapsular percutaneously-assisted total hip (SuperPATH) approach on muscle injury. METHODS: Forty-nine patients undergoing initial THA via SuperPATH approach between June 2022 and June 2023 were randomly divided into two groups, with 24 patients in trial group and 25 patients in control group. The trial group received piriformis muscle release intraoperatively, whereas the control group underwent muscle preservation. There was no significant difference in baseline data such as gender, age, body mass index, disease type, American Society of Anesthesiologists (ASA) grading, and preoperative muscle infiltration, muscle atrophy, muscle injury serological indicators, Harris score, etc. ( P>0.05). The incision length, operation time, intraoperative blood loss, total blood loss, hospital stay, preoperative and postoperative 1-day muscle injury serological indicators [including creatine kinase (CK) and lactic dehydrogenase (LDH)], and incidence of complications between two groups were recorded. Harris score was used to evaluate the recovery of hip joint function. MRI was used to evaluate the extent of hip muscle injuries (gluteus minimus, gluteus medius, piriformis, obturator internus, quadratus femoris), including tendon integrity, degree of muscle fat infiltration, and degree of muscle atrophy preoperative and 1 year postoperatively. RESULTS: The operation time, intraoperative blood loss, and total blood loss in the trial group were significantly shorter than those in the control group ( P<0.05). There was no significant difference in the incision length and length of hospital stay between the two groups ( P>0.05). Both groups showed a significant increase in serum CK and LDH levels on postoperative day 1 compared to preoperative levels ( P<0.05), but there was no significant difference between the two groups ( P>0.05). All patients were followed up, the follow-up time for the trial group and the control group was (14.8±2.8) and (15.1±3.0) months, respectively, with no significant difference ( t=-0.400, P=0.691). Incisions healed by first intention in both groups, with 1 case in the trial group and 2 cases in the control group experiencing venous thrombosis in the calf muscle space. There was no complication such as deep vein thrombosis, pulmonary embolism, hip dislocation, prosthesis loosening, or periprosthetic infection in the lower limbs. There was no significant difference in the incidence of complications between the two groups ( P>0.05). At 1 year after operation, both groups of patients showed a significant increase in Harris scores compared to preoperative levels ( P<0.05), but there was no significant difference between the two groups ( P>0.05). Compared with preoperative results, both groups showed significant fat infiltration in the piriformis and obturator muscles at 1 year after operation ( P<0.05), while there was no significant fat infiltration in the gluteus minimus, gluteus medius, and quadratus femoris muscles ( P>0.05). At 1 year after operation, except for the higher incidence of piriformis muscle fat infiltration in the control group compared to the trial group ( P<0.05), there was no significant difference in the incidence of other muscle infiltrations between the two groups ( P>0.05). At 1 year after operation, both groups of piriformis and obturator muscles showed significant muscle atrophy compared to preoperative levels ( P<0.05). The gluteus minimus and gluteus medius showed mild atrophy compared to preoperative levels, while the maximum transverse diameter of the quadriceps muscle slightly increased, but the differences were not significant ( P>0.05). There was no significant difference in the maximum cross-sectional diameter or cross-sectional area changes of each muscle between the two groups ( P>0.05). At 1 year after operation, the continuity of the gluteus medius and quadratus femoris muscles in both groups was intact. Both groups had some patients with incomplete continuity of the piriformis muscle, obturator internus, and gluteus minimus, but the difference was not significant ( P>0.05). CONCLUSION The SuperPATH approach THA may cause injury to the piriformis, gluteus minimus, and obturator internus. The piriformis muscle release does not increase muscle injury, but it can shorten the operation time and reduce bleeding.
Humans ; Arthroplasty, Replacement, Hip/adverse effects* ; Male ; Female ; Muscle, Skeletal/surgery* ; Middle Aged ; Aged ; Postoperative Complications/epidemiology* ; Adult ; Operative Time ; Muscular Atrophy ; Creatine Kinase/blood* ; Length of Stay ; Treatment Outcome

Spinal muscular atrophy (SMA) is a common fatal autosomal recessive genetic disorder in childhood, primarily caused by homozygous deletion of the SMN1 gene. Its main characteristics include the degenerative changes in the anterior horn motor neurons of the spinal cord, leading to symmetrical progressive muscle weakness and atrophy of the proximal limbs. However, SMA patients with the same genetic background often exhibit different degrees of disease severity. In addition to the well-established modifier gene SMN2, the effect of other modifier genes on clinical phenotypes should not be overlooked. This paper reviews the latest advancements in the pathogenic and modifier genes of SMA, aiming to provide a deeper understanding of the pathogenic mechanisms and phenotypic differences in SMA, as well as to offer new strategies and targets for treating this condition.
Humans ; Muscular Atrophy, Spinal/genetics* ; Phenotype ; Survival of Motor Neuron 1 Protein/genetics* ; Genes, Modifier ; Survival of Motor Neuron 2 Protein/genetics*

OBJECTIVES: To explore the efficacy and adverse reactions of nusinersen combined with risdiplam in the treatment of spinal muscular atrophy (SMA). METHODS: A retrospective analysis was conducted on the clinical data of 10 pediatric SMA patients treated with nusinersen combined with risdiplam at the Children's Medical Center of Xiangya Hospital, Central South University. RESULTS: Among the 10 SMA patients, there were 4 with type I, 4 with type II, and 2 with type III. Nine patients initially received nusinersen monotherapy, while 1 patient received nusinersen combined with risdiplam. The median duration of combination therapy with nusinersen and risdiplam for the 10 patients was 10.5 months (range: 0.5-20.0 months), with 6 patients undergoing combination therapy for more than 6 months, showing improvements in motor and/or respiratory function. The remaining 4 patients had combination treatment durations of 0.5, 1.0, 1.3, and 4.0 months, respectively, with no significant overall improvement. After combined treatment, 5 patients experienced skin hyperpigmentation, 2 had lumbar puncture site pain, 1 experienced vomiting, 1 had increased sputum production, and 1 had reduced total sleep time. All adverse reactions were mild and did not require medical intervention. CONCLUSIONS Nusinersen combined with risdiplam demonstrates efficacy in the treatment of SMA, and no significant adverse reactions have been observed.
Humans ; Oligonucleotides/adverse effects* ; Male ; Female ; Child, Preschool ; Retrospective Studies ; Infant ; Muscular Atrophy, Spinal/drug therapy* ; Drug Therapy, Combination ; Child ; Azo Compounds ; Pyrimidines

OBJECTIVE: To assess the carrier frequency of spinal muscular atrophy (SMA) in women of childbearing age in Chongqing and to evaluate prenatal diagnostic outcomes in high-risk couples. METHODS: A total of 17 926 women of childbearing age attending Chongqing Health Center for Women and Children between May 2021 and November 2023 were enrolled, including 3 398 pre-pregnant women and 14 528 pregnant women, all of whom had no clinical phenotype or family history of SMA or related neuromuscular disorders. Real-time quantitative PCR (RT-qPCR) was used to determine the copy number variations in exons 7 and 8 (E7, E8) of the SMN1 gene. High-risk carriers were identified based on the genetic screening results. Multiplex ligation-dependent probe amplification (MLPA) was employed for prenatal diagnosis of fetuses from high-risk couples. This study was approved by the Medical Ethics Committee of Chongqing Health Center for Women and Children (Ethics No.2021-RGI-02). RESULTS: Among the 17 926 women of childbearing age, 298 (1.66%) were identified as heterozygous carriers, including 278 (1.55%) with concurrent deletions of E7 and E8, and 20 (0.11%) with isolated deletions of E7. Seven high-risk couples were identified, six of whom were prenatal couples. Of the two fetuses from these high-risk pregnancies, both exhibited heterozygous deletions of E7 and E8 in the SMN1 gene, while four fetuses showed no abnormalities. CONCLUSION This study provides a comprehensive assessment of the carrier frequency of SMA among women of childbearing age in Chongqing, offering valuable data for the primary and secondary prevention of SMA-related birth defects in the region.
Humans ; Female ; Muscular Atrophy, Spinal/diagnosis* ; Pregnancy ; Prenatal Diagnosis/methods* ; Adult ; Survival of Motor Neuron 1 Protein/genetics* ; Genetic Carrier Screening/methods* ; DNA Copy Number Variations/genetics* ; China ; Genetic Testing ; Heterozygote

The maintenance of skeletal muscle quality involves various signal pathways that interact with each other. Under normal physiological conditions, these intersecting signal pathways regulate and coordinate the hypertrophy and atrophy of skeletal muscles, balancing the protein synthesis and degradation of muscle. When the total rate of protein synthesis exceeds that of protein degradation, the muscle gradually becomes enlarged, while when the total rate of protein synthesis is lower than that of protein degradation, the muscle shrinks. Myocyte atrophy mainly involves two protein degradation pathways, namely ubiquitin-proteasome and autophagy-lysosome. Protein degradation pathway is activated during muscle atrophy, resulting in the loss of muscle mass. Muscle atrophy can occur under various conditions such as malnutrition, aging and cachexia. Skeletal muscle atrophy caused by orthopedic diseases mainly includes disuse muscular atrophy caused by fracture and denervation muscular atrophy. The signal pathways that control and coordinate protein synthesis and degradation in skeletal muscle include insulin-like growth factor 1 (IGF1)-Akt-mammalian target of rapamycin (mTOR), myostatin-activin A-Smad, G protein α inhibitory peptide 2 (Gαi2)-PKC, nuclear factor κB (NF-κB), ectodysplasin A2 receptor (EDA2R)-NF-κB inducing kinase (NIK) and mitogen-activated protein kinase (MAPK) pathways. This paper provides a comprehensive review of the protein degradation pathways in skeletal muscle atrophy and the associated signal pathways regulating protein degradation in muscular atrophy.
Humans ; Muscular Atrophy/etiology* ; Muscle, Skeletal/pathology* ; Signal Transduction ; Animals ; Insulin-Like Growth Factor I/metabolism* ; Myostatin/physiology* ; TOR Serine-Threonine Kinases/metabolism* ; Autophagy/physiology* ; NF-kappa B/metabolism* ; Proteolysis ; Proteasome Endopeptidase Complex/physiology*

Objective: To investigate the clinical features and gene variation characteristics of children with dynein cytoplasmic 1 heavy chain 1 (DYNC1H1) gene associated spinal muscular atrophy with lower extremity predominant (SMALED) 1. Methods: The clinical data of 4 SMALED1 children admitted to Peking University First Hospital from December 2018 to May 2021, who were found to have pathogenic variation of DYNC1H1 gene through genetic testing, except for other genes known to be related to motor retardation, were retrospectively summarized to analyze the phenotype and genotype characteristics. Results: There were 3 males and 1 female. The age of onset was 1 year, 1 day, 1 day and 4 months, respectively. The age of diagnosis was 4 years and 10 months, 9 months, 5 years and 9 months, and 3 years and 1 month, respectively. The clinical manifestations were muscle weakness and muscular atrophy of lower limbs, 2 cases with foot deformity, 1 case with early non progressive joint contracture, 1 case with hip dislocation and 1 case with mental retardation. De novo heterozygous missense variations in DYNC1H1 gene were found in all 4 children. According to the rating of American College of medical genetics and genomics, they were all possible pathogenic and pathogenic variations, with p.R598C, p.P776L, p.Y1109D variations had been reported, and p.I1086R variation had not been reported. Conclusions: For those with unexplained lower limb muscle weakness, muscle atrophy, joint contracture and foot deformity, upper limb motor ability related retention, with or without mental retardation, as well as the motor ability progresses slowly, it is necessary to consider the possibility of SMALED1 and the detection of DYNC1H1 gene when necessary.
Female ; Male ; Humans ; Intellectual Disability ; Retrospective Studies ; Muscular Atrophy, Spinal/genetics* ; Lower Extremity ; Muscle Weakness ; Muscular Atrophy ; Contracture ; Cytoplasmic Dyneins/genetics*

Humans ; Muscular Atrophy, Spinal/therapy*