BACKGROUND:Sarcopenia obesity is characterized by the coexistence of sarcopenia and obesity with a continuously increasing prevalence.Aerobic exercise can alleviate the progression of sarcopenic obesity,but the overall metabolic changes in skeletal muscle after exercise are still unclear.OBJECTIVE:To investigate the effects of exercise on various aspects of the energy metabolic pathways in the skeletal muscle of mice with sarcopenic obesity.METHODS:Male C57BL/6J mice were randomly divided into normal control(normal diet)and model(high-fat diet)groups.After 12 weeks of feeding,sarcopenic obesity model mice were screened by body mass and behavior assessments.The sarcopenia obesity mice were then divided into the sedentary and exercise groups.Mice in the exercise group were subjected to treadmill training on the basis of a high-fat diet.After 8 weeks of intervention,body mass,lipid metabolism,muscle volume of calf muscle group of the hind limb,skeletal muscle morphology,and expressions of energy metabolic pathway-related genes were detected.RESULTS AND CONCLUSION:Compared with the normal control group,the levels of triglycerides,total cholesterol,and free fatty acid in the sedentary group were significantly increased,along with significantly increased lipid droplets in skeletal muscle(P<0.05).Compared with the sedentary group,all of the above indicators in the exercise group showed a significant decreasing trend(P<0.05).Compared with the normal control group,grip strength and fatigue latency time,muscle volume,and fiber cross-sectional area were significantly decreased in the sedentary group,but the mRNA expression of Atrogin-1 and Murf-1 was elevated(P<0.05).Compared with the sedentary group,grip strength and fatigue latency time,muscle volume,and fiber cross-sectional area were significantly improved in the exercise group(P<0.05),while the mRNA expression of Atrogin-1 and Murf-1 was reduced(P<0.05).Compared with the normal control group,the mRNA expression of intramuscular transcription factors Pparα and Pgc-1α was decreased in the sedentary group(P<0.05),the mRNA expression of fatty acid synthesis-related enzymes Srebp1c and Fasn was elevated(P<0.05),and the mRNA expression of the β-oxidation system Cpt1β,Acox1,Acox3 and fatty acid metabolism Arf1 and Plin3 was decreased(P<0.05).Compared with the sedentary group,the abnormal expression of the above genes was significantly reversed in the exercise group(P<0.05).To conclude,aerobic exercise can alleviate lipid deposition and improve muscle quality and strength of sarcopenic obesity mice by regulating the expression of genes in the intramuscular energy metabolism network.

BACKGROUND:Sarcopenia obesity is characterized by the coexistence of sarcopenia and obesity with a continuously increasing prevalence.Aerobic exercise can alleviate the progression of sarcopenic obesity,but the overall metabolic changes in skeletal muscle after exercise are still unclear.OBJECTIVE:To investigate the effects of exercise on various aspects of the energy metabolic pathways in the skeletal muscle of mice with sarcopenic obesity.METHODS:Male C57BL/6J mice were randomly divided into normal control(normal diet)and model(high-fat diet)groups.After 12 weeks of feeding,sarcopenic obesity model mice were screened by body mass and behavior assessments.The sarcopenia obesity mice were then divided into the sedentary and exercise groups.Mice in the exercise group were subjected to treadmill training on the basis of a high-fat diet.After 8 weeks of intervention,body mass,lipid metabolism,muscle volume of calf muscle group of the hind limb,skeletal muscle morphology,and expressions of energy metabolic pathway-related genes were detected.RESULTS AND CONCLUSION:Compared with the normal control group,the levels of triglycerides,total cholesterol,and free fatty acid in the sedentary group were significantly increased,along with significantly increased lipid droplets in skeletal muscle(P<0.05).Compared with the sedentary group,all of the above indicators in the exercise group showed a significant decreasing trend(P<0.05).Compared with the normal control group,grip strength and fatigue latency time,muscle volume,and fiber cross-sectional area were significantly decreased in the sedentary group,but the mRNA expression of Atrogin-1 and Murf-1 was elevated(P<0.05).Compared with the sedentary group,grip strength and fatigue latency time,muscle volume,and fiber cross-sectional area were significantly improved in the exercise group(P<0.05),while the mRNA expression of Atrogin-1 and Murf-1 was reduced(P<0.05).Compared with the normal control group,the mRNA expression of intramuscular transcription factors Pparα and Pgc-1α was decreased in the sedentary group(P<0.05),the mRNA expression of fatty acid synthesis-related enzymes Srebp1c and Fasn was elevated(P<0.05),and the mRNA expression of the β-oxidation system Cpt1β,Acox1,Acox3 and fatty acid metabolism Arf1 and Plin3 was decreased(P<0.05).Compared with the sedentary group,the abnormal expression of the above genes was significantly reversed in the exercise group(P<0.05).To conclude,aerobic exercise can alleviate lipid deposition and improve muscle quality and strength of sarcopenic obesity mice by regulating the expression of genes in the intramuscular energy metabolism network.