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

Abstract

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)). MItrained 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.

Effect of Swimming Training and Crocin Consumption on Intrinsic Apoptosis Pathway in Muscle Tissue of High-Fat Diet-induced Obese Rats

“…Moreover, the increase of protein kinase B (PKB) is a major actor in the phosphatidylinositol-3 kinase (PI3K) signaling pathway that plays a role in cellular processes, including cell survival, metabolism, cell growth, and proliferation. Increased expression and enhanced PKB activity inhibit apoptotic pathways by phosphorylation of anti-apoptotic proteins of the Bcl-2 family and inactivation of apoptotic promoter proteins such as Bax and BAK or directly by controlling caspase activity (12). However, researchers believe that physical activity is a potential source of oxidative stress and can lead to the imbalance of proinflammatory and inflammatory cytokines and cell death (21).…”

“…It was found that high-intensity interval training and low-intensity continuous training had significant effects on increased Bcl-2 and decreased P53 levels in the heart tissue of rats although low-intensity continuous training had no significant effect on reduced Bax level in rats (11). Moreover, high-intensity interval training was effective on reduced caspase-9 levels in the heart tissue of rats with myocardial infarction (12). It seems that the type of training and training physiology in different settings have different effects on the physiology of the body, as the study by Charmas and Gromisz stated that swimming training had a significant effect on the improvement of physical composition (13).…”

“…It seems that regular exercise activities can prevent tissue damage by reducing oxidative stress and increasing antioxidants. However, the intensity of exercise, the type of exercise, and the length of the training period are among the most important factors in the anti-apoptotic effects of sports exercises (11,12). It was found that high-intensity interval training and low-intensity continuous training had significant effects on increased Bcl-2 and decreased P53 levels in the heart tissue of rats although low-intensity continuous training had no significant effect on reduced Bax level in rats (11).…”

Molecular mechanisms of exercise contributing to tissue regeneration

“…39,302,303 Overall, CITED4 acts as downstream of C/ EBPβ, thereby activating the mTOR pathway, promoting exerciseinduced cardiomyocyte proliferation and protecting from adverse cardiac remodeling. [303][304][305] Another potential downstream mediator of the cell proliferation and development induced by exercise are forkhead box class O family (FOXOs). Akt/FOXO3a signaling pathway is activated in exercise-induced autophagy, which is beneficial for remedying sarcopenia.…”