Study On The Effect Of Exercise Training On Cardiac Structure And Function Of The Myocardial Infarction Rat

Objective:To explore the positive influence of 8 weeks of different exercise training [high intensity interval training(HIIT)and moderate intensity continuous training(MICT)]on the architecture and features of the heart from acute myocardial infarction(AMI)rats.Methods:Twenty-four male SD rats were successfully established as AMI models and were randomly classified into AMI+ sedentary group(SED),AMI + HIIT training group(HIIT group),and AMI + MICT training group(MICT group),and eight rats in per group.Another 8 rats of the same category were taken for sham surgery(only threading without ligating the LAD)and these 8 rats were included in the sham surgery group(Sham group).After 1 week of AMI modeling of the rats,the HIIT and MICT groups started exercise training,and the Sham and SED groups did not undergo any exercise intervention,and data and specimens were collected from the rats at the end of the 8-week exercise training.Results:In the rats in both the MICT and HIIT groups,myocardial microvascular density(MVD)was dramatically increased compared to the Sham and SED groups after 8weeks of exercise training(P<0.05);left ventricular ejection fraction(LVEF)was significantly improved in the MICT and HIIT groups versus the rats in the SED group(P<0.05),and the area of myocardial fibrosis was remarkably reduced(P<0.05),but there was no statistical difference between MICT and HIIT(P>0.05).Exercise significantly upregulated myocardial mi R-21 expression and activated the mi R-21-PTEN-Akt signaling pathway to improve cardiac function in infarcted rats.Pearson correlation analysis showed that myocardial mi R-21 expression was significantly negatively correlated with myocardial fibrosis(r=-0.804,P<0.05)and positively correlated with the number of new blood vessels and LVEF(r=0.799,P<0.05;r=0.834,P<0.05).Conclusion:Exercise training could effectively improve cardiac function and reduce the level of myocardial fibrosis after AMI in rats with no significant difference between HIIT and MICT;HIIT and MICT could stimulate vascular neovascularization in the marginal zone of AMI,and there was no statistical difference between the two exercise modalities;exercise training significantly upregulated myocardial mi R-21 expression and activated mi R-21-PTEN-Akt signaling pathway to improve cardiac function in rats with infarction,and there was no significant difference between MICT and HIIT.