Effect Of Exercise On Mitochondrial Autophagy Of Skeletal Muscle And The Function Of FUNDC1

Objective: To investigate the effect of different time length and different intensity exercises on the mitochondrial autophagy of skeletal muscle and the function of FUNDC1,a treadmill exercise program was established to observe the effect of exercise during 2 weeks or 4 weeks,with moderate intensive exercise or high intensive exercise on the mitochondrial structure and function of skeletal muscle.To verify the mitochondrial autophagy pathway of skeletal muscle mediated by FUNDC1 and induced by exercise with immunofluorescence and mitochondrial autophagy protein expression changes.Methods: Sixty male SD rats were divided into 2 weeks of quiet control group(2Con),2 weeks of moderate intensive exercise group(2M-ex),2 weeks of intensive exercise group(2Hi-ex),4 weeks of quiet control group(4Con),4 weeks of moderate intensive exercise group(4M-ex)and 4 week intensive exercise group(4Hi-ex),soleus muscle is separated for detection.The mitochondrial,autophagy and so on ultrastructural changes in skeletal muscle was observed by transmission electron microscope during different time length and different intensity exercises to study the morphological changes;the protein expressions of PGC-1? and COX-I were detected by Western blot;the content of mitochondrial number mark enzyme CS were measured to analyze the changes of mitochondrial function;the co-localization of LC3 and FUNDC1 was observed by immunofluorescence double staining combined with laser confocal microscopy.The protein expressions of AMPK?? p-AMPK?(Thr172)?ULK1? FUNDC1? LC3? p62 were detected with Western blot to verify the function of FUNDC1 in the autophagy pathway.Results:(1)The group of 4 weeks under moderate intensive exercise and intensive exercise group were observed more and larger mitochondria,both sides of the sarcomere and muscle film gathere more obvious than 2 weeks under the same intensive exercise groups.The expression of autophagy associated protein expression,PGC-1?,COX-I and CS content are higher than 2 weeks of the same intensive exercise groups(p < 0.05).(2)Intensive exercise autophagy marker protein LC3,p62 expressions are more than moderate intensive exercise group during the same time length,but PGC-1?,COX-I protein expression are less than moderate intensive exercise group,CS content is less than moderate intensive exercise group(p < 0.05)(3)The results of the immunofluorescence bidyed results show that the co-localization of FUNDC1 and LC3 respectively with mitochondria increases after the exercise.And the expression of autophagy related protein AMPK?,p-AMPK?(Thr172),ULK1,FUNDC1,LC3 and p62 increase(p < 0.05).Conclusion:(1)After exercising,skeletal muscle mitochondrial structure and function changes obviously,the mitochondrial autophagy protein expression,biosynthesis of mitochondria and mitochondrial function of 4 weeks under moderate intensive exercise and intensive exercise respectively higher than the same intensive exercise group of 2 weeks.(2)The intensive exercise group have higher autophagy in the medium intensive exercise group,and the mitochondrial synthesis and mitochondria quantity decrease,and the large intensive exercise could cause the mitochondrial function to be damaged(3)Exercise induces AMPK? protein expression increase,increases ULK1,and then phosphorylates outer membrane protein FUNDC1,which connects LC3 to induce autophagy.