The effect of 8 weeks of vitamin D supplementation and aerobic exercise on sirtuin-1 protein levels and oxidative stress markers of myocardial tissue in middle-aged male rats

Exercise training and vitamin D supplementation play an important role in cardiovascular health. However, the effects of combining these two strategies and their molecular role in cardiac adaptations are less known. Therefore, the present study was conducted with the aim of determining the effect of vitamin D supplementation and aerobic exercise on oxidative stress markers and Sirtuin-1 (SIRT-1) levels in the myocardial tissue of middle-aged male rats.

Forty male rats (12-14 months, 350-400 g) after two weeks of familiarization and maximal aerobic speed test, were randomly divided into four groups: control (Con), aerobic training (AT), vitamin D (Vit-D) and aerobic exercise + vitamin D (AT+Vit_D) were divided. The training consisted of eight weeks of incremental training (5 days per week). Vit_D and AT+Vit-D groups received 500 units of vitamin D along with 0.3 ml of olive oil (kg/body weight). Olive oil was also used as a placebo. 48 hours after the last intervention session, the heart tissue of the animals was removed. The activities of Superoxide dismutase (SOD) and Glutathione peroxidase (GPx) as well as the concentration of Malondialdehyde (MDA), Hydrogen peroxide (H2O2) and SIRT-1 protein were measured. Data analysis was done by one-way ANOVA test at P < 0.05 level.

The findings showed that the SIRT-1 was significantly higher in the AT than in the Con group (P < 0.05). Also, the MDA levels in the AT were lower than in the Con group (P < 0.05). No significant difference was observed in MDA and SIRT-1 among other groups (P > 0.05). In addition, there was no significant difference in the ‌ GPx, SOD and H2O2 between the groups (P > 0.05).

In general, the findings of the present study showed that regular aerobic exercise is beneficial for reducing oxidative damage to the heart tissue in middle age. Also, aerobic training in middle age leads to an increase in SIRT-1 protein. Considering the important role of SIRT-1 in preventing heart diseases and strengthening the antioxidant defense system, aerobic exercise seems to be an effective strategy to reduce cardiovascular diseases associated with aging. In addition, the findings of the present study showed that vitamin D supplementation along with aerobic exercise does not produce synergistic effects in improving oxidative stress markers or SIRT-1. However, due to the small amount of studies in this regard and also some limitations of the current research, it is suggested to conduct more studies in this regard.