A novel modulatory role of vitamin D₃ in exercise-induced apoptosis of rat skeletal muscle.

摘要

The present study has been designed to investigate the possible modulating role of vitamin D₃ on chronic exercise-induced apoptosis in skeletal (gastrocnemius) muscle of rats. Rats were run for 8 weeks on a treadmill at a speed of 36 m min-1 to induce apoptosis in their skeletal muscle. Vitamin D₃ (0.03 micro g/100 g and 0.06 micro g/100 g, s.c.) treatment, thrice weekly, was started three days prior to subjecting the animals to chronic exercise and was continued for 8 weeks of the experimental protocol. Oxidative stress was assessed by measuring the levels of TBARS, super oxide anion generation and reduced glutathione in gastrocnemius muscle. Further, serum level of corticosterone (glucocorticoid), a potent indicator of stress, was measured. Moreover, the apoptotic cell death was assessed using DNA gel electrophoresis. Chronic treadmill exercise produced profound DNA smearing. The levels of TBARS, super oxide anion generation and serum corticosterone were noted to be increased and the level of GSH was noted to be decreased in rats subjected to chronic treadmill exercise. However, treatment with vitamin D₃ markedly reduced DNA smearing. Moreover, the chronic exercise-induced increases in TBARS level, superoxide anion generation and corticosterone levels were significantly attenuated by treatment with vitamin D₃. In addition, vitamin D₃ markedly increased the exercise-induced decrease in GSH level. It suggests that antioxidant potential of vitamin D₃ and its novel efficacy in modulating exercise-induced corticosterone levels in rats may contribute to its anti-apoptotic effect.