Anti‑aging effects of melatonin on the myocardial mitochondria of rats and associated mechanisms.

The present study investigated the anti-aging effects of melatonin on the myocardial mitochondria of D-galactose-aged rats and associated mechanisms. A total of 30 male Sprague‑Dawley (SD) rats were randomly divided into three equal groups: An accelerated aging group that received 125 mg/kg/day D‑galactose; a melatonin‑treated group of D‑galactose‑aged rats that received 10 mg/kg/day melatonin; and a control group receiving normal saline. ATP, ADP and AMP levels in the left ventricular myocardium of rats were determined by high performance liquid chromatography and the total adenylic acid number (TAN) was subsequently calculated. Bax, Bcl‑2, and cytochrome c (cyt‑c) protein expression levels in myocardial mitochondria and cytoplasm were quantified by western blot analysis. In the melatonin‑treated group, ATP levels were significantly higher when compared with the untreated control group and the accelerated‑ageing group (0.068 vs. 0.052 and 0.058; P=0.002 and P=0.045, respectively), and TAN was significantly increased in the melatonin‑treated group when compared with controls (P=0.011). In addition, cyt‑c levels in the cytoplasm, but not in the mitochondria, were significantly higher in the accelerated‑aging group compared with the control and melatonin‑treated groups (P=0.001 and P=0.002, respectively). Bcl‑2 and Bax ratios were significantly higher in the control and melatonin‑treated groups when compared with the accelerated‑aging group (P=0.004 and P=0.032, respectively). These results suggest that melatonin exhibits a protective effect on mitochondrial function in a rat model of accelerated aging.