The Effects of Exercise Training Intensity on the Expression of C/EBPβ and CITED4 in Rats with Myocardial Infarction

Background: Exercise training (ET) has a cardioprotective effect and can induce new cardiomyocyte formation in physiological cardiac remodeling. However, following a large myocardial infarction (MI), the changes in cardiac regeneration and the subsequently different intensities of ET remain unexplored. We investigated the effect of different intensities of ET on the expression of C/EBPβ and CITED4 after an MI. Methods: Adult male Wistar rats were exposed to left coronary artery ligation (LAD). Following an echocardiographic evaluation at four weeks after surgery, MI-operated animals were randomly assigned to either the MI-sedentary (MI-Sed) or the MI-trained groups (low intensity interval training (LIIT), moderate intensity interval training (MIIT), and high intensity interval training (HIIT)). MI-trained animals performed six weeks ET protocols (five days/week). Results: Ten weeks after surgery, HIIT and MIIT animals had significantly higher LV ejection fraction compared to MI-Sed animals. HIIT animals had significantly diminished mRNA levels of C/EBPβ compared to MI-Sed. The mRNA level of CITED4 in HIIT and MIIT were significantly high compared to MI-Sed. Conclusions: The present study demonstrates that cardiac functions are ET intensity-dependent, following a MI. It seems that higher intensities of ET are most effective agents in promoting the expression of C/EBPβ and CITED4. Thus, ET has emerged as an important variable in preclinical and clinical investigations.