Effects of Continuous and Interval Aerobic Exercise on Expressions of Myostatin and Its Receptor in Infarcted heart

Objectives:To discuss the influence of continuous and interval aerobic exercise on myocardial myostatin, ActRIIB and myocardial function in myocardial infarction (MI) rats.Methods:3-month-old male Sprague-Dawley rats were randomly divided into:sedentary control group (A) , sedentary MI group (B) , MI with continuous aerobic exercise group (C) and MI with aerobic interval training group (D) .The MI model in rats were established by ligation of left anterior descending (LAD) coronary artery.After a 5day's adaptability training (10~15m/min, 30min/d) , rats in Group C were subjected to 8week treadmill training at the speed of 16m/min for 60min/d, 5d/wk and rats in Group D warmed up at the speed of 10m/min on the treadmill for 10min at first, and then ran at the speed of 25m/min for 7min, 15m/min for3min, sequentially alternating, 60min/d, 5d/wk, total 8 weeks.Hemodynamic measurement and electrocardiogram were performed to evaluate the cardiac function after 8weeks training.Then the hearts were picked out and expression levels of myostatin, ActRIIB, α-actin andα-myosin were detected by RT-PCR, Western Blot or immunofluorescence.Results:Compared to control rats, the MI rats were found to have impaired cardiac function and decreased the expression levels ofα-actin andα-myosin, increased the expression levels of Myostatin and ActRIIB.Continuous and aerobic interval training both can increase the expressions ofα-actin andα-myosin and decrease the expressions of Myostatin and ActRIIB significantly, but the latter is better.Conclusion:Both continuous and aerobic interval training can effectively promote myocardial function, which related to increasing the expression levels ofα-actin andα-myosin and decreasing the levels of Myostatin and ActRIIB, and aerobic interval training has a better effect.