Caloric restriction alleviates ischemia-reperfusion-induced myocardial injury in elderly mice via the AKT-mTOR pathway

Caloric restriction (CR) has been shown to improve cardiac function, especially to restore cardiac tolerance during ischemia-reperfusion(I/R). However, evidence about the effects of caloric restriction on the myocardium of aged mice during I/R and mechanisms remain scarce. Our aim was to fill the gap by establishing a mouse model. We determined the effects of CR on fat content, adiponectin and leptin by ELISA. Blood glucose, insulin-related indexes, intraperitoneal glucose tolerance test (IP-GTT) and ultrastructure were also recored and analyzed in aged mice and young mice after I/R. In addition, we also examined the related proteins expression levels of AKT-mTOR pathway in mouse cardiac tissue by Western blot. The results showed that the fat content, the blood glucose and insulin levels decreased after CR, the adiponectin and leptin increased after CR. Besides, CR relieved myocardial injury in mice induced by I/R. Additionally, compared with the elderly ad libitum (AL) group, the expression levels of p-Akt, p-ULK ₁ , and p-FoxO ₁ proteins in the elderly CR group increased, while the protein levels of p-raptor and p-mTOR decreased. Overall, our results suggested that Akt-mTOR-induced autophagy was involved in the relief of myocardial injury in aged mice on I/R after CR.