OBJECTIVE To investigate the influence of CYP2C19 gene polymorphism on platelet function and inflammatory cytokines in elderly patients with ischemic stroke， and to analyze potential factors associated with poor prognosis. METHODS A retrospective study was conducted on elderly patients with ischemic stroke admitted to our hospital from June 2024 to June 2025， wh o underwent CYP2C19 genotype testing and received antiplatelet therapy with clopidogrel. The levels of platelet function indicators and inflammatory cytokines before and after treatment were compared among patients with different metabolic phenotypes. Based on the prognosis at 6 months post-treatment， patients were divided into poor prognosis group and good prognosis group. Univariate analysis was performed on general data， metabolic phenotype， the levels of platelet function indicators and inflammatory cytokines. Variables with P ＜0.05 and the levels of inflammatory cytokines before treatment were included in a multivariate Logistic regression analysis to identify independent risk factors for poor prognosis. Multiple linear regression was used to further analyze the relationship between metabolic phenotypes and inflammatory cytokines. RESULTS A total of 448 elderly patients with ischemic stroke were included； among them， 162 cases were normal metabolic phenotype， 218 were intermediate metabolic phenotype， and 68 were poor metabolic phenotype. No rapid or ultrarapid metabolic phenotypes were observed. After treatment， platelet aggregation rate， the levels of P-selectin and platelet activated complex-1 （PAC-1）， high-sensitivity C-reactive Protein （hs-CRP）， interleukin-1β （IL-1β）， IL-6 and tumor necrosis factor-α （TNF-α） in the normal metabolic phenotype group， intermediate metabolic phenotype group， and poor metabolic phenotype group （except for platelet aggregation rate， and the levels of P-selectin and PAC-1 in the poor metabolic phenotype group） were significantly lower than those before treatment in the same group. Moreover， the above indicators in the normal metabolic phenotype group were significantly lower than those in the intermediate and poor metabolic phenotype groups at the corresponding time， and the levels of platelet function indicators in the intermediate metabolic phenotype group were significantly lower than those in the poor metabol ic phenotype group at the corresponding time （ P ＜0.05）. Univariate and multivariate Logistic regression analyses showed that combined with hypertension， combined with diabetes mellitus， and intermediate or poor metabolic genotypes were independent risk factors for poor prognosis in elderly patients with ischemic stroke （ P ＜0.05）. Multiple linear regression analysis showed that serum levels of hs-CRP， IL-1β， IL-6 and TNF-α before treatment were significantly higher in patients with intermediate and poor metabolic genotypes compared to those with normal metabolic genotype （ P ＜0.05）， with a greater magnitude of increase in inflammatory cytokines observed in the patients with poor metabolic genotype. CONCLUSIONS The elderly ischemic stroke patients with CYP2C19 intermediate and poor metabolic genotypes have poor inhibition effect on platelet and higher levels of inflammatory cytokines than normal metabolic genotype； CYP2C19 gene polymorphism， and in combination with hypertension and diabetes， can be used as independent predictors of poor prognosis.

ObjectiveTo optimize the extraction method for polysaccharides from turnip（Brassica rapa）， and analyze and evaluate the primary structure of the isolated and purified turnip polysaccharide fraction（BP-1） and its hypoglycemic effects in diabetic zebrafish. MethodsTaking polysaccharide yield as the evaluation index， a semi-bionic extraction method was employed. Single-factor experiments and Box-Behnken response surface methodology were used to investigate three factors of solid-to-liquid ratio， extraction time and extraction temperature， in order to optimize the extraction process. BP-1 was isolated and purified using the Sevage method and DEAE-52 cellulose column chromatography. Structural characterization of the turnip polysaccharides was performed using ultraviolet-visible spectrophotometry（UV）， gas chromatography-mass spectrometry（GC-MS）， Congo red assay， and Fourier-transform infrared spectroscopy（FT-IR） to determine purity， monosaccharide composition， triple-helix structure， and functional groups. The microstructure of the polysaccharides was observed using scanning electron microscopy（SEM） and atomic force microscopy（AFM）. Zebrafish were divided into the blank group（adding E3 medium）， and BP-1-1， BP-1-10， BP-1-50， BP-1-200， BP-1-1 000 groups（adding BP-1 solutions at concentrations of 1， 10， 50， 200， 1 000 mg·L^-1， respectively）， and zebrafish embryos were subjected to a 96-hour exposure experiment. The maximum tolerated concentration of BP-1 in zebrafish was determined by evaluating its effects on phenotype， survival rate， malformation rate， and heart rate. Experimental animals were randomly divided into the blank group， model group， BP-1-10 group（10 mg·L^-1）， BP-1-50 group（50 mg·L^-1）， and BP-1-200 group（200 mg·L^-1）. The blank group was cultured in E3 medium， the model and treatment groups were induced to establish a diabetic model in 4 day-post-fertilization（dpf） zebrafish embryos using 10 g·L^-1 of glucose combined with 500 µmol·L^-1 of alloxan. The treatment groups received corresponding doses of BP-1 solution， while the blank and model groups received an equal volume of saline. Glucose and insulin（INS） levels were measured using enzyme-linked immunosorbent assay（ELISA） kits， the effects on the liver were observed by hematoxylin-eosin（HE） histopathological sections. The mRNA expression levels of glucagon（Glucagon）， insulin（Insa）， and phosphoenolpyruvate carboxykinase 1（PCK1） were detected with real-time fluorescence quantitative polymerase chain reaction（Real-time PCR）. ResultsThe optimized extraction conditions were determined as follows：solid-to-liquid ratio of 1∶40（g·mL^-1）， extraction time of 66 min， and extraction temperature of 79 ℃. Under these conditions， the yield of turnip polysaccharides was （10.34±0.96）%. UV analysis indicated that BP-1 contained no proteins or nucleic acids， GC-MS analysis revealed that BP-1 consisted of six monosaccharides（arabinose， rhamnose， ribose， mannose， galactose and glucose）. Congo red assay indicated that the molecular conformation did not exhibit a triple-helix structure， FT-IR analysis showed the presence of α-glycosidic bonds and uronic acids， SEM analysis revealed an irregular flaky structure with a flat and smooth surface， AFM analysis suggested that the aggregated structure might be formed by the entanglement of molecular chains and intramolecular hydrogen bonding. The maximum tolerated concentration of BP-1 in zebrafish over 96 h was determined to be 200 mg·L^-1. Pharmacodynamic results showed that， compared with the blank group， the model group exhibited significantly increased glucose levels and significantly decreased INS levels（P<0.01）. Compared with the model group， the BP-1-50 group significantly reduced glucose levels and increased INS levels（P<0.05）. Histopathological examination of liver tissue revealed that various doses of BP-1 had a certain reparative effect on damaged liver tissue. The liver tissue structure in the BP-1-200 group was nearly normal， with hepatocytes appearing plump. Real-time PCR results showed that， compared with the blank group， the model group exhibited significantly upregulated mRNA expressions of Glucagon and PCK1， and significantly downregulated mRNA expression of Insa（P<0.01）. Compared with the model group， the BP-1-50 and BP-1-200 groups showed significantly downregulated mRNA expressions of Glucagon and PCK1， and significantly upregulated mRNA expression of Insa（P<0.01）. ConclusionThe semi-bionic extraction method for turnip polysaccharides yields a high extraction rate， is simple to operate， has low costs， making it suitable for large-scale industrial production. BP-1 consists of six monosaccharides， contains α-glycosidic bonds and uronic acids， exhibits hypoglycemic activity， and provides a certain protective effect on the liver of alloxan-induced diabetic model zebrafish.

ObjectiveTo optimize the extraction method for polysaccharides from turnip（Brassica rapa）， and analyze and evaluate the primary structure of the isolated and purified turnip polysaccharide fraction（BP-1） and its hypoglycemic effects in diabetic zebrafish. MethodsTaking polysaccharide yield as the evaluation index， a semi-bionic extraction method was employed. Single-factor experiments and Box-Behnken response surface methodology were used to investigate three factors of solid-to-liquid ratio， extraction time and extraction temperature， in order to optimize the extraction process. BP-1 was isolated and purified using the Sevage method and DEAE-52 cellulose column chromatography. Structural characterization of the turnip polysaccharides was performed using ultraviolet-visible spectrophotometry（UV）， gas chromatography-mass spectrometry（GC-MS）， Congo red assay， and Fourier-transform infrared spectroscopy（FT-IR） to determine purity， monosaccharide composition， triple-helix structure， and functional groups. The microstructure of the polysaccharides was observed using scanning electron microscopy（SEM） and atomic force microscopy（AFM）. Zebrafish were divided into the blank group（adding E3 medium）， and BP-1-1， BP-1-10， BP-1-50， BP-1-200， BP-1-1 000 groups（adding BP-1 solutions at concentrations of 1， 10， 50， 200， 1 000 mg·L^-1， respectively）， and zebrafish embryos were subjected to a 96-hour exposure experiment. The maximum tolerated concentration of BP-1 in zebrafish was determined by evaluating its effects on phenotype， survival rate， malformation rate， and heart rate. Experimental animals were randomly divided into the blank group， model group， BP-1-10 group（10 mg·L^-1）， BP-1-50 group（50 mg·L^-1）， and BP-1-200 group（200 mg·L^-1）. The blank group was cultured in E3 medium， the model and treatment groups were induced to establish a diabetic model in 4 day-post-fertilization（dpf） zebrafish embryos using 10 g·L^-1 of glucose combined with 500 µmol·L^-1 of alloxan. The treatment groups received corresponding doses of BP-1 solution， while the blank and model groups received an equal volume of saline. Glucose and insulin（INS） levels were measured using enzyme-linked immunosorbent assay（ELISA） kits， the effects on the liver were observed by hematoxylin-eosin（HE） histopathological sections. The mRNA expression levels of glucagon（Glucagon）， insulin（Insa）， and phosphoenolpyruvate carboxykinase 1（PCK1） were detected with real-time fluorescence quantitative polymerase chain reaction（Real-time PCR）. ResultsThe optimized extraction conditions were determined as follows：solid-to-liquid ratio of 1∶40（g·mL^-1）， extraction time of 66 min， and extraction temperature of 79 ℃. Under these conditions， the yield of turnip polysaccharides was （10.34±0.96）%. UV analysis indicated that BP-1 contained no proteins or nucleic acids， GC-MS analysis revealed that BP-1 consisted of six monosaccharides（arabinose， rhamnose， ribose， mannose， galactose and glucose）. Congo red assay indicated that the molecular conformation did not exhibit a triple-helix structure， FT-IR analysis showed the presence of α-glycosidic bonds and uronic acids， SEM analysis revealed an irregular flaky structure with a flat and smooth surface， AFM analysis suggested that the aggregated structure might be formed by the entanglement of molecular chains and intramolecular hydrogen bonding. The maximum tolerated concentration of BP-1 in zebrafish over 96 h was determined to be 200 mg·L^-1. Pharmacodynamic results showed that， compared with the blank group， the model group exhibited significantly increased glucose levels and significantly decreased INS levels（P<0.01）. Compared with the model group， the BP-1-50 group significantly reduced glucose levels and increased INS levels（P<0.05）. Histopathological examination of liver tissue revealed that various doses of BP-1 had a certain reparative effect on damaged liver tissue. The liver tissue structure in the BP-1-200 group was nearly normal， with hepatocytes appearing plump. Real-time PCR results showed that， compared with the blank group， the model group exhibited significantly upregulated mRNA expressions of Glucagon and PCK1， and significantly downregulated mRNA expression of Insa（P<0.01）. Compared with the model group， the BP-1-50 and BP-1-200 groups showed significantly downregulated mRNA expressions of Glucagon and PCK1， and significantly upregulated mRNA expression of Insa（P<0.01）. ConclusionThe semi-bionic extraction method for turnip polysaccharides yields a high extraction rate， is simple to operate， has low costs， making it suitable for large-scale industrial production. BP-1 consists of six monosaccharides， contains α-glycosidic bonds and uronic acids， exhibits hypoglycemic activity， and provides a certain protective effect on the liver of alloxan-induced diabetic model zebrafish.

ObjectiveTo explore the expression levels of long non-coding RNA （lncRNA） H19 and microRNA-22-3p （miR-22-3p） in the serum of patients with acute myocardial infarction （AMI） and their diagnostic value for AMI. MethodsA total of 176 AMI patients were selected as the experimental group and were divided into ST-segment elevation myocardial infarction （STEMI） group （n=95） and non-ST-segment elevation myocardial infarction （NSTEMI） group （n=81） based on their medical history and electrocardiogram. Meanwhile， 156 patients with negative angiography during the same period were selected as the control group （CON group）. The relative expression levels of lncRNA H19 and miR-22-3p in the serum of the two groups were detected by real-time fluorescence quantitative polymerase chain reaction. The diagnostic value of miR-22-3p and lncRNA H19 in AMI was evaluated by receiver operating characteristic curve （ROC） analysis. The levels of serum cardiac troponin I （cTnI）， creatine kinase （CK）， creatine kinase MB isoenzyme （CK-MB）， and high-sensitivity C-reactive protein （CRP） were detected in all study subjects. Spearman correlation analyses were used to evaluate the correlations between lncRNA H19 and miR-22-3p and cTnI， CK， CK-MB and CRP. ResultsCompared with the control group， the expression level of lncRNA H19 was upregulated and the expression level of miR-22-3p was downregulated in the AMI group （all P<0.01）； compared with the NSTEMI group， the expression level of lncRNA H19 was upregulated and the expression level of miR-22-3p was downregulated in the STEMI group （P<0.01）. The areas under the ROC curves （AUC） for the diagnosis of AMI by miR-22-3p， lncRNA H19 and their combination were 0.555， 0.977， and 0.983， respectively. lncRNA H19 was positively correlated with cTnI， CK， CK-MB and CRP （P<0.05）， and negatively correlated with left ventricular ejection fraction （LVEF） （P<0.001）； miR-22-3p was negatively correlated with cTnI， CK and CRP， and positively correlated with LVEF （P<0.05）. ConclusionThe expression level of lncRNA H19 is elevated and the expression level of miR-22-3p decreased in AMI patients， and their levels may have potential value as an auxiliary biomarker for AMI diagnosis and cardiac function assessment.

Objective: To conduct a scoping review on the types, construction methods and predictive performance of health literacy prediction models based on machine learning methods, so as to provide the reference for the improvement and application of such models. Methods: Publications on health literacy prediction models conducted using machine learning methods were retrieved from CNKI, Wanfang Data, VIP, PubMed and Web of Science from inception to May 1, 2024. The quality of literature was assessed using the Prediction Model Risk of Bias ASsessment Tool. Basic characteristics, modeling methods, data sources, missing value handling, predictors and predictive performance were reviewed. Results: A total of 524 publications were retrieved, and 22 publications between 2007 and 2024 were finally enrolled. Totally 48 health literacy prediction models were involved, and 25 had a high risk of bias (52.08%), with major issues focusing on missing value handling, predictor selection and model evaluation methods. Modeling methods included regression models, tree-based machine learning methods, support vector machines and neural network models. Predictors primarily encompassed factors at four aspects: individual, interpersonal, organizational and society/policy aspects, with age, educational level, economic status, health status and internet use appearing frequently. Internal validation was conducted in 14 publications, and external validation was conducted in 4 publications. Forty-two models reported the areas under the receiver operating characteristic curve, which ranged from 0.52 to 0.983, indicating good discrimination. Conclusion Health literacy prediction models based on machine learning methods perform well, but have deficiencies in risk of bias, data processing and validation.

Hyperlipidemic acute pancreatitis(HLAP)is triggered by severe disturbances in lipid metabolism,progresses rapidly,and is associated with a high risk of complications.Its pathogenesis involves multiple mechanisms,including chylomicron accumulation and free fatty acid toxicity,activation of inflammatory pathways,and disruption of intracellular calcium homeostasis.Recent studies have shown that polymorphisms in lipid metabolism-related genes can influence HLAP susceptibility,disease severity,and lipid-lowering drug efficacy by regulating lipoprotein metabolism,fatty acid oxidation,and inflammatory responses.This article systematically reviews the associations between major lipid metabolism gene polymorphisms and HLAP/hypertriglyceridemia,gene-gene and gene-environment interactions,and the potential impact of these polymorphisms on the therapeutic responses to fibrates,statins,and PCSK9 inhibitors.It also discusses the current status and challenges of genotype-based individualized prevention and treatment strategies,aiming to provide a theoretical basis and future directions for precision screening and personalized management of HLAP.

Objective To observe the effect of a heavy load exercise on the ultrastructure,function and fission of skeletal muscle mitochondria in rats,and to analyze the changes of the phosphorylation expression of mitochondrial fission protein and upstream kinase at different times postexercise,and to explore the effect of acute heavy load exercise on mitochondrial fission in skeletal muscle of rats and its possible mechanism.Methods Forty-eight adult male Sprague-Dawley rats were randomly divided in-to a quiet control group(C,n=8)and an exercise group(E,n=40).Rats in the E group exercised on a treadmill down a 16° decline at 16 m/min for 90 min and were further divided into 0 h,12 h,24 h,48 h,and 72 h postexercise subgroups.Soleus muscle was isolated and mitochondria were ex-tracted at the corresponding time points after exercise.The ultrastructure of mitochondria in the soleus muscle was observed using transmission electron microscopy,and mitochondrial quantity and morphomet-ric analysis were conducted.Moreover,the colocalization and quantity of dynamin-related protein 1(Drp1)and cytochrome C oxidease subunit Ⅳ(COXⅣ)in the soleus muscle were detected using im-munofluorescence double-labeling techniques.Meanwhile,protein levels of soleus musclep-Drp1Ser616,p-Drp1Ser637,p-extracellular regulatory protein kinaseThr202/Tyr204(p-ERKThr202/Tyr204),p-protein kinaseAThr197(p-PKAThr197),and mitochondrial NADH of ubiquinone oxidoreductase subunit B8(NDUFB8)and ubiqui-nol-cytochrome C reductase core protein 2(UQCRC2)were determined by using Western blotting.An-other twenty-four rats were randomly divided into a DMSO group(CD),a U0126 group(CU),an Ex-ercise+DMSO group(ED),and an Exercise+U0126 group(EU).Six mice in each group were giv-en a single intra-bitoneal injection of DMSO or ERK inhibitor U0126 20 min before acute downhill running.Then,their phosphorylated expressions of ERKThr202/Tyr204 and Drp1Ser616 in soleus muscle were de-tected by Western blotting.Results(1)From 0 h to 48 h after exercise,the soleus muscle mitochon-dria showed swelling,rounding,and uneven distribution of mitochondria,among which the degree of mitochondrial damage was the most serious at 12 h and 24 h after exercise.Moreover,the protein ex-pression of NDUFB8 and UQCRC2 in the mitochondria fractions from soleus muscle was significantly lower at 12 h post-exercise(P<0.05).(2)The co-localization of Drp1 and COXⅣ in the skeletal muscle increased significantly at 12 h to 24 h after a heavy load exercise compared with group C and group E0(P<0.01).Moreover,the mitochondrial area,circumference,aspect ratio and Ferret diameter in the skeletal muscle were significantly lower at 12 h to 24 h postexercise(P<0.05).Meanwhile,the number of mitochondria was significantly higher at 24 h after exercise(P<0.01).(3)The phosphoryla-tion of ERKThr202/Tyr204,PKAThr197 and Drp1Ser616 was significantly higher at 24 h after exercise(P<0.01),while that of Drp1Ser637 was significantly lower at 48 h and 72 h post-exercise(P<0.01).However,the phosphorylated expressions of ERKThr202/Tyr204 and Drp1Ser616 were significantly down-regulated by U0126 treatment before exercise.Conclusion A session of heavy load exercise caused mitochondrial structure and function damage and induced mitochondrial fission in the skeletal muscle,and then to maintain the homeostasis of skeletal muscle cells by cleaving damaged mitochondria.The mechanism of promot-ing skeletal muscle repair may be related to the positive and negative regulation of Drp1 activity by the phosphorylation of Drp1Ser616 and Drp1Ser637,respectively.Among them,the activation of ERKThr202/Tyr204 mediates the phosphorylation activation of Drp1Ser616,but PKAThr197 is not an upstream kinase that medi-ates the inactivation of Drp1Ser637 phosphorylation.

The interaction between epithelial cells and macrophages plays a crucial role in the progression of lung diseases,including immune de-fense,inflammation regulation,tissue repair,and regeneration.However,an imbalance in this inter-action can contribute to the development of vari-ous lung diseases.In idiopathic pulmonary fibrosis,chronic obstructive pulmonary disease,and lung cancer,macrophages can promote disease progres-sion by secreting cytokines that act on epithelial cells.Simultaneously,activated epithelial cells re-lease cytokines to recruit and activate more macro-phages in a positive feedback loop.Thus,compre-hensive studies of the interactions between epithe-lial cells and macrophages in various lung diseases have the potential to identify new therapeutic tar-gets and develop innovative strategies for disease management.This review aims to summarize the current knowledge regarding the interaction be-tween epithelial cells and macrophages in idiopath-ic pulmonary fibrosis,chronic obstructive pulmo-nary disease,and lung cancer,with the goal of in-spiring new research directions for the treatment of lung diseases.

Objective:To systematically search and summarize high-quality evidence-based evidence on the prevention and management of refeeding syndrome in patients with anorexia nervosa, and to provide a basis for preventive management of patients at high risk.Methods:A computerized search was conducted for evidence on the prevention and management of refeeding syndrome in patients with anorexia nervosa in relevant domestic and international databases and professional team websites, including clinical decision-making, guidelines, expert consensus, evidence summaries and systematic evaluations, and randomized controls. The search timeframe was from database construction to August 2024. Two researchers trained in systematic evidence-based knowledge independently performed literature screening, quality assessment, and extraction and summarization of evidence according to inclusion and exclusion criteria.Results:A total of 15 publications were included, which contained 4 guidelines, 3 expert consensus, 3 clinical decision-making, 3 systematic evaluations, and 2 randomized control trials. Thirty-one pieces of evidence for the prevention and management of refeeding syndrome were summarized in seven areas: treatment team, risk factors, risk assessment, preventive measures, clinical diagnosis, management measures, and patient safety.Conclusions:The best evidence summarized in this study for the prevention and management of refeeding syndrome in anorexia nervosa provides an evidence-based basis for practitioners to implement refeeding syndrome prevention and management measures.

Objective To observe the effect of a heavy load exercise on the ultrastructure,function and fission of skeletal muscle mitochondria in rats,and to analyze the changes of the phosphorylation expression of mitochondrial fission protein and upstream kinase at different times postexercise,and to explore the effect of acute heavy load exercise on mitochondrial fission in skeletal muscle of rats and its possible mechanism.Methods Forty-eight adult male Sprague-Dawley rats were randomly divided in-to a quiet control group(C,n=8)and an exercise group(E,n=40).Rats in the E group exercised on a treadmill down a 16° decline at 16 m/min for 90 min and were further divided into 0 h,12 h,24 h,48 h,and 72 h postexercise subgroups.Soleus muscle was isolated and mitochondria were ex-tracted at the corresponding time points after exercise.The ultrastructure of mitochondria in the soleus muscle was observed using transmission electron microscopy,and mitochondrial quantity and morphomet-ric analysis were conducted.Moreover,the colocalization and quantity of dynamin-related protein 1(Drp1)and cytochrome C oxidease subunit Ⅳ(COXⅣ)in the soleus muscle were detected using im-munofluorescence double-labeling techniques.Meanwhile,protein levels of soleus musclep-Drp1Ser616,p-Drp1Ser637,p-extracellular regulatory protein kinaseThr202/Tyr204(p-ERKThr202/Tyr204),p-protein kinaseAThr197(p-PKAThr197),and mitochondrial NADH of ubiquinone oxidoreductase subunit B8(NDUFB8)and ubiqui-nol-cytochrome C reductase core protein 2(UQCRC2)were determined by using Western blotting.An-other twenty-four rats were randomly divided into a DMSO group(CD),a U0126 group(CU),an Ex-ercise+DMSO group(ED),and an Exercise+U0126 group(EU).Six mice in each group were giv-en a single intra-bitoneal injection of DMSO or ERK inhibitor U0126 20 min before acute downhill running.Then,their phosphorylated expressions of ERKThr202/Tyr204 and Drp1Ser616 in soleus muscle were de-tected by Western blotting.Results(1)From 0 h to 48 h after exercise,the soleus muscle mitochon-dria showed swelling,rounding,and uneven distribution of mitochondria,among which the degree of mitochondrial damage was the most serious at 12 h and 24 h after exercise.Moreover,the protein ex-pression of NDUFB8 and UQCRC2 in the mitochondria fractions from soleus muscle was significantly lower at 12 h post-exercise(P<0.05).(2)The co-localization of Drp1 and COXⅣ in the skeletal muscle increased significantly at 12 h to 24 h after a heavy load exercise compared with group C and group E0(P<0.01).Moreover,the mitochondrial area,circumference,aspect ratio and Ferret diameter in the skeletal muscle were significantly lower at 12 h to 24 h postexercise(P<0.05).Meanwhile,the number of mitochondria was significantly higher at 24 h after exercise(P<0.01).(3)The phosphoryla-tion of ERKThr202/Tyr204,PKAThr197 and Drp1Ser616 was significantly higher at 24 h after exercise(P<0.01),while that of Drp1Ser637 was significantly lower at 48 h and 72 h post-exercise(P<0.01).However,the phosphorylated expressions of ERKThr202/Tyr204 and Drp1Ser616 were significantly down-regulated by U0126 treatment before exercise.Conclusion A session of heavy load exercise caused mitochondrial structure and function damage and induced mitochondrial fission in the skeletal muscle,and then to maintain the homeostasis of skeletal muscle cells by cleaving damaged mitochondria.The mechanism of promot-ing skeletal muscle repair may be related to the positive and negative regulation of Drp1 activity by the phosphorylation of Drp1Ser616 and Drp1Ser637,respectively.Among them,the activation of ERKThr202/Tyr204 mediates the phosphorylation activation of Drp1Ser616,but PKAThr197 is not an upstream kinase that medi-ates the inactivation of Drp1Ser637 phosphorylation.