The Effects Of Different Exercises On Skeletal Muscle Atrophy-related Proteins MuRF1, MAFbx, IGF-1 And Caspase-3

Objective: To observe the effects of different exercise interventions on disuse muscle atrophy(SMDA).To investigate the relationship between muscle atrophic proteins MuRF1,MAFbx,IGF-1 and Caspase-3 and SMDA under exercise intervention.Methods: Fifty-six male Sprague-Dawley rats aged 8 weeks were randomly divided into control group(C group,n=16)and suspension group(T group,n=40).Group C was not treated,and group T was suspended for 2 weeks using the tail suspension system(TSS).After 2 weeks,group C was randomly divided into blank control group 1(C1 group,n=8)and blank control group 2(C2 group,n=8).The T component was immediately after suspension(T1 group,n= 8),control group after suspension(TC group,n=8),aerobic exercise group(TA group,n=8),resistance exercise group(TR group,n=8)and aerobic and resistance exercise combined group(TAR)Group,n=8).After 2 weeks of suspension,body weight,gastrocnemius wet weight,body weight and gastrocnemius wet weight ratio were measured in the C1 group and the T1 group.The cross-sectional area(CSA)of the muscle fibers was observed by HE staining,and the gastrocnemius CSA was calculated by Image J software.The protein expressions of MuRF1,MAFbx,Caspase-3 and IGF-1 in the gastrocnemius of C1 and T1 rats were determined by Western blot.The rats in the C2 group and the TC group did not exercise.The rats in the TA group,the TR group and the TAR group underwent 4 weeks of aerobic exercise,resistance exercise,and aerobic and resistance combined with exercise intervention.After 4 weeks,the rats in each group were tested by the same method.index.Result:(1)After 2 weeks of tail suspension,compared with C1 group,T1 weight,gastrocnemius wet weight,gastrocnemius wet weight/body weight ratio and CSA decreased significantly;gastrocnemius MuRF1,MAFbx and Caspase-3 protein expression increased significantly,IGF-1 The expression of MuRF1,MAFbx,Caspase-3 and IGF-1 protein was not significantly different in the TC group than in the C2 group.The difference was not significant.(2)After 4 weeks of exercise intervention,the wet weight of the gastrocnemius,the wet weight/body weight ratio of the gastrocnemius and the CSA were significantly higher in the TA group,the TRgroup and the TAR group than in the TC group and the C2 group;the expression of MuRF1 protein in the TA group and the TR group was significantly lower than that in the TC group.The expression of MAFbx protein in TA,TR and TAR groups was significantly higher than that in TC group and C2 group.The expression of Caspase-3protein in the three exercise groups was significantly lower than that in the TC group and the C2 group,and the expression of IGF-1 protein was higher than that in the TC group and the C2 group.Conclusion:(1)After 2 weeks of tail suspension,significant muscle atrophy occurred in the gastrocnemius of rats,and the expression of MuRF1,MAFbx and Caspase-3 protein in skeletal muscle atrophy protein was increased,and the expression of anti-atrophic protein IGF-1 was decreased.(2)Suspension for 2 weeks After 4 weeks of natural recovery,the muscle atrophy state and related proteins can return to normal levels;(3)4 weeks of different exercise intervention can effectively relieve muscle atrophy caused by braking,and significantly increase the wet weight of the gastrocnemius muscle and the wet weight of the gastrocnemius.Body weight ratio and CSA are particularly evident in resistance exercise and resistance to aerobic exercise,and the mechanism may be related to down-regulation of MuRF1,Caspase-3and up-regulation of IGF-1 protein expression.