عباسعلی گائینی - Dept.of Exercise Physiology, University of Shiraz, Shiraz, Iran
محمد همتی نفر - Dept. of Exercise Physiology, University of Tehran, Tehran

Background and Objective: Exercise training (ET) has cardioprotective effects and can induce new cardiomyocyte formation in physiological cardiac remodeling. Sca-۱ is one of the most important surface markers of cardiac stem cells, which repair heart muscle following myocardial infarction (MI). The purpose of this study was to investigate the effects of exercise training intensity on the gene expression of Sca۱ in rats with MI. Materials and Methods: Male Wistar rats underwent LAD coronary artery ligation surgery, the occurrence of MI was then confirmed by echocardiography. Four weeks after surgery, the rats with MI were divided randomly into groups including low-intensity training (LIT), moderate intensity training (MIT), high-intensity training (HIT), MI-Sedentary (MI-SED) and a sham group (Sham). Training groups performed exercise training protocols for ۶ weeks. The rats were sacrificed after the exercise training interventions and the data obtained from their cardiac tissues were analyzed via one-way ANOVA and Bonferroni tests. Results: Results showed that values of ejection fraction, fractional shortening and Sca-۱ mRNA have a significant difference among all groups (P<۰.۰۵). Results demonstrated that ejection fraction and fractional shortening values in the exercise training groups increased significantly compared to the MI-SED group. However, their values were significantly lower compared to the Sham group. LIT significantly increased mRNA levels of Sca-۱ compared with MI-SED. Conclusion: It seems that low-intensity interval training improves cardiac function and is more effective on the mRNA levels of Sca-۱ in rats with MI.    

Key words: Myocardial infarction, Heart Failure, Exercise training intensity, Sca-۱ gene