Effect Of Resistance And Endurance Exercise On Expression Of MuRF-1,MAFbx And Caspase-3 MRNA In Skeletal Muscle Of Ageing SAMP8 Mice

Exercise can lead to skeletal muscle hypertrophy preventing atrophy.Proteolytic events involve the ubiquitination and subsequent degradation of proteins marked by E3 ligases.Exercise-responsive genes involved in the muscle cell ubiquit proteasome pathway system include muscle ring finger-1(MuRF-1),and atrogin-1(muscle atrophy F-box),both of which share a common transcription factor,In catabolic states where proteolysis is increased,two genes specific to muscle atrophy,MuRF-1 and MAFbx,are upregulated.These encode ubiquitin ligases,which bind to and mediate ubiq-uitination of myofibrillar proteins for subsequent degradation during muscle atroph.proteolytic system dEs not break down actomyosin complexes R myofibrils, even though it degrades monomelic actin or myosin.Since cytokines or insulin resistance are common in catabolic states and will activate caspases.Exercise can cause skeletal muscle hypertrophy,but the different exercise form,load exercise, exercise frequency can make a great difference to skeletal muscle hypertrophy, simultaneously also displays to difference expression of MuRF-1,MAFbx and the Caspase-3.21 SAMP8 senile male mice were divide into three groups randomly.Elderly control(C),elderly endurance exercise(E),elderly resistance exercise groups(R). Choose treadmill exercise as endurance training mode;the training,Selection of the laddering weight training as resistance training mode.The mice after eight weeks training,the musculature were dyed by HE then observed by light microscope in Rder to obtain the gastrocnemius muscle in the cross-sectional area.The other musculature were detected by real-time fluorescence staining by quantitatie polymerase chain reaction(PCR) method to get expression level of MuRF-1 mRNA,MAFbx mRNA,Caspase-3 mRNA.From the aspects of muscular atrophy and apoptosis, investigating different influence of old mice skeletal muscles in movement patterns.Results:1)The senile SAMP8 mice underwent eight weeks of the endurance exercise and resistance exercise.before and after exercise,The difference was not statistically significant(P＞0.05).After training the ratio of the weight in wet base of gastrocnemius to weight(RM),RM of resistance exercise group is greater than endurance exercise group and control group,has extremely significant significant(P＜ 0.01),endurance exercise group is greater than control group,has no significant difference(P＞0.05).2)relative expression of MAFbx mRNA:endurance exercise is lower than controls group,has statistically significant(P＜0.05).resistance exercise group is lower than controls group,has extremely significant significant(P＜0.01),endurance exercise group is lower than control group,has no significant difference(P＞0.05).3)relative expression of MuRF-1 mRNA:endurance exercise is lower than controls group,has extremely statistically significant(P＜0.01).resistance exercise group is lower than controls group,has extremely significant significant(P＜0.01), endurance exercise group is lower than control group,has no significant difference(P＞0.05).4)relative expression of Caspase-3 mRNA:endurance exercise is lower than controls group,has statistically significant(P＜0.01).resistance exercise group is lower than controls group,has significant significant(P＜0.05),endurance exercise group is lower than control group,has no significant difference(P＞0.05).5)CSA of skeletal muscle fibers:endurance exercise is greater than controls group, has no significant difference(P＞0.05).resistance exercise group is greater than controls group,has extremely significant significant(P＜0.01),endurance exercise group is lower than control group,has no significant difference(P＜0.05).Conclusions:1)after The senile SAMP8 mice underwent eight weeks resistance exercise,the expression level of MuRF-1 mRNA,MAFbx mRNA,caspase-3 mRNA are decreased evidently in gastrocnemius,the cross-sectional area and relative mass of gastrocnemius are increased significantly.2)after The senile SAMP8 mice underwent eight weeks endurance exercise,the expression level of MuRF-1 mRNA,MAFbx mRNA,caspase-3 mRNA are decreased evidently in gastrocnemius,the cross-sectional area and relative mass of gastrocnemius have no significantly change.3)resistance exercise cause Skeletal muscle hypertrophy,in a certain extent,by reducing the gene expression level of correlative proteolytic factRs to achieve in skeletal muscle.4)Though endurance exercise can not cause skeletal muscle hypertrophy,the gene expression level of correlative proteolytic factors are reduced after training,the metabolism of skeletal muscle may be improved by endurance training.