Voluntary Wheel Running Or Ladder-climbing Exercise Protects Against Myocardial Damage In Aged Rats

Objective: In the present study,we simulated the natural aging model by normal feeding of SD rats until 21 months.Two exercise modes including voluntary wheeling running and ladder-climbing intervention were used for 8 consecutive weeks,respectively.The purpose of this study is to explore the protective effect of exercise intervention on aging myocardium and its underlying mechanisms,thereby providing the guidance for exploring exercise prescription for the elderly.Methods: Totally 20 aged male rats were randomly divided into three groups including senior control group(OC,n = 8),senior ladder-climbing group(OP,n = 6),and senior voluntary wheel running group(OZ,n = 6).After exercise intervention for 8 weeks,the myocardium of rats was evaluated by transmission electron microscope.The expression of proteins correlated with autophagy,apoptosis,heat shock insults,energy metabolism,and antioxidant function was detected by Western blot analysis.Results:1.Compared with the control group,the ordered structure and better function of mitochondria in rats from the experimental group were observed.Compared with the control group,the regularly arranged structure of myofibrils in the experimental group were examined.2.Compared with the control group,the expression of Beclin-1,AMPK,Sirt1,PGC-1?,HSF1/HSP72 and Keap1/Nrf2 proteins in the OP group were increased significantly(p <0.05),and the expression of p62 and Bax proteins in the OP group was decreased significantly(p < 0.05).Similarly,the expression of Atg7,Beclin-1,Bcl-2,AMPK,Sirt1,PGC-1?,HSF1/HSP72 and Keap1/Nrf2 proteins in the OZ group was increased significantly(p < 0.05);in contrast,the expression of p62 and Bax proteins in the OZ group was decreased significantly(p < 0.05).Conclusion:1.Exercise intervention can execute the protection of myocardium in aging rats through inducing autophagy and suppressing apoptosis.2.Exercise intervention accomplishing the protein of myocardium of aging rats throughincreasing antioxidant activity and reducing oxidative stress-induced injury.3.Exercise intervention protects against myocardium of aging rats through promoting energy metabolism and improving myocardial mitochondrial function.4.Exercise throughincreasing myocardial heart shock proteins level to protect myocardium;5.Exercise has many beneficial effects on the aging myocardium,and it is suggested that the elderly keep exercise with appropriate intensity.