[Effects of aerobic interval training on myocardial oxidative stress and inflammation in rats with myocardial infarction and its mechanism].

Objective

The present study was to determine the effects of aerobic interval training (AIT) on the expressions of SIRT1, Nox4 and inflammatory factor in the heart of rats with myocardial infarction (MI).

Methods

Male Sprague Dawley rats were randomly divided into sham-operated group (C), sedentary MI group (MI) and MI with AIT group (ME) (n=10). The MI model was established by ligation the left anterior descending coronary artery. Rats in C groups were subjected to the same surgery, but only threaded and not ligated. After surgery 1 week, rats in ME groups took adaptability training for 1 week, and then subjected to 4 weeks treadmill exercise training. After training, the hearts were collected for histological observation. The level of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in heart was assessed by ultraviolet spectrophotometry. The activity of lactate dehydrogenase (LDH) was determined by enzyme linked immunosorbent assay. The expression of sirtuin1 (SIRT1) mRNA was examined by real-time quantitative polymerase chain reaction (RT-qPCR). The protein expressions of SIRT1, NADPH oxidase 4 (Nox4), tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) were detected by Western blotting. The levels of reactive oxygen species (ROS) were detected by dihydroethidium (DHE) staining.

Results

Compared with the C group, the expression level of cardiac Nox4 protein was increased (P＜0.01), the level of MDA, activity of LDH and the level of ROS were increased significantly (P＜0.01), and the expressions of TNF-α and IL-1β protein were augmented in the heart of rats with MI (P＜0.01). However, the expressions of SIRT1 mRNA and protein and the activity of SOD were obviously decreased in MI group (P＜0.01). Furthermore, compared with the MI group, AIT increased the expressions of SIRT1 mRNA and protein and the activity of SOD in the heart of ME group (P＜0.01); Meanwhile, the expressions of cardiac Nox4, MDA level, LDH activity and ROS level were diminished in ME group (P＜0.01) as well as the decreased expressions of TNF-α and IL-1β protein (P＜0.01). SIRT1 expression was negatively related to the expressions of NOX4 and ROS.

Conclusion

AIT obviously inhibited myocardial oxidative stress and inflammatory reaction, improved cardiac function in rats with MI, and the mechanism was closely related to the activation of SIRT1-Nox4-ROS signaling pathway.