Influence of high-intensity interval training and intermittent fasting on myocardium apoptosis pathway and cardiac morphology of healthy rats

Aim: To evaluate the influence of intermittent fasting and high-intensity interval training (HIIT) on myocardial apoptosis signaling and cardiac morphological characteristics in healthy rats. Methods: Male Wistar rats (n = 60) were divided into four groups: sedentary control (SED-C), intermittent fasting (SED-IF), high-intensity interval training (HIIT-C), and high-intensity interval training plus intermittent fasting (HIIT-IF). SED-C and HIIT-C groups were treated daily with ad libitum chow; SED-IF and HIIT-IF received the same standard chow every other day. HIIT-C and HIIT-IF rats were submitted to an HIIT protocol five times a week for 12 weeks. At the end of the experiment, functional capacity, cardiac morphology, and expression of apoptosis signaling pathways-related proteins were analyzed. Key findings: HIIT increased cardiomyocyte cross-sectional area, collagen interstitial fraction, and the proapoptotic proteins AIF and caspase-3 expression, and reduced pro-apoptotic protein CYTC expression and the cleaved-to-non-cleaved PARP-1 ratio in myocardium. Intermittent fasting reduced cardiomyocyte cross-sectional area, collagen interstitial fraction, and expression of Bax, CYTC and cleaved PARP-1, and increased expression of the anti-apoptotic protein BCL-2. SMAC, ARC, and caspase-8 expression was not changed by HIIT or intermittent fasting. Significance: HIIT promotes cardiomyocyte hypertrophy and interstitial fibrosis, and modulates the apoptosis signaling pathway in healthy rat myocardium. Intermittent fasting reduces pro-apoptotic and increases antiapoptotic signaling, besides attenuating HIIT-induced cardiomyocyte hypertrophy and myocardial interstitial fibrosis.

Automated summary

The study shows that high-intensity interval training promotes cardiomyocyte hypertrophy and interstitial fibrosis in healthy rat myocardium, while also modulating the apoptosis signaling pathway. Conversely, intermittent fasting reduces cardiomyocyte hypertrophy, collagen interstitial fraction, and pro-apoptotic protein expression, and increases antiapoptotic protein expression.