Effects Of Aerobic Exercise On Telomerase Activity And Cell Proliferation Of Myocardial Cells In Rats After MI

Objective:The effects of aerobic exercise on telomerase activity of rat myocardial cells and cardiac myocyte proliferation after MI had been investigated.Methods:Thirty male SD rats were divided randomly into 3 groups,it was included control(sham),myocardial infarction(MI)and myocardial infarction exercise(ME)group,10 in each group.Operation of the left anterior descending coronary artery was designed to establish the MI model.Except no ligation of the Sham group,the remaining procedure as with other groups.For ME group,there was an 8-weeks of intermittent aerobic exercise after one week of myocardial infarction surgery.After the end of the experiment,we detected the ventricular thickness and ejection function of rats with two-dimensional echocardiogram.The ratio of heart weight to body weight and left ventricular weight to body weight was counted.The expression level of plasma and myocardium insulin growth factor was detected with ELISA.The GATA4 and Nkx2.5mRNA level of cardiac muscle tissue was detected with RT-qPCR to measure the capacity of myocardial cells proliferation.The activity of myocardial telomerase was detected with ELISA,and the mRNA level of TERT and TERC was detected with RT-qPCR.Results:1.The surgery of myocardial infarction resulted in reducing of rat myocardial cell,thinning of cardiac ventricular wall and reducing of ejection function.Compared with the Sham group,the ejection fraction(EF)of MI group significantly decreased(P?0.01),as well as the ratio of HW/BW and LVW/BW(P?0.05vs.P<0.05).After 8 weeks of intermittent aerobic exercise,the sum of posterior wall of left ventricular thickness and ventricular septum thickness in diastole and the value of EF of ME group were significantly increased than MI group(P<0.05vs.P?0.05vs.P?0.05).2.Intermittent aerobic exercise after myocardial infarction activated myocardial cell proliferation of rat.The expression of IGF-1 in plasma and myocardium was significantly higher in ME group than in MI group(P<0.05vs.P<0.05).Compared with the Sham group,the expression level of Nkx2.5 mRNA was significantly increased in MI group(P?0.05),while the GATA4 and Nkx2.5mRNA expression level of myocardium was significantly increased in ME group than in MI group(P?0.01vs.P?0.05).3.Intermittent aerobic exercise after myocardial infarction can apparently increase the level of telomerase expression in myocardial tissue of rats.The telomerase expression level of myocardium was significantly increased in ME group than in MI group(P?0.01).Compared with the Sham group,the TERT mRNA expression level of myocardium was significantly increased in MI group(P?0.05),while the protein expression level of myocardial telomerase and the mRNA expression level of TERT and TERC was significantly increased in ME group than in MI group(P?0.01vs.P?0.01).Conclusions:1.The intermittent aerobic exercise could obviously promote the edge area of myocardial infarction myocardial cell proliferation after MI,improve heart function..2.Intermittent aerobic exercise could activate telomerase activity in cardiomyocytes of rats after MI,and promote the proliferation of cardiomyocytes.