Effect of two protocols of high interval and continuous training on the levels of antioxidant enzymes in the liver of old rats

Ageing is associated with changes in the function of liver cells and the development of chronic liver disease. According to the theory of free radicals, the process of cellular aging is the result of a mutation caused by active oxygen species, more oxidative stress, and impairment in antioxidant defense of the cell. Exercise with the induction of antioxidant enzymes reduces free radicals and also prevents the aging process from producing free radicals. The aim of the present study was to investigate the effect of two protocols of interval and continuous training on the levels of antioxidant enzymes in the liver of old male rats.

An experimental study was conducted on 21 healthy rats (22-24 months). The rats were randomly divided into three groups: high intensity interval training (HIIT) (n=7), moderate-intensity continuous training (MCT) (n=7), and control group (n=7). A routine interval training program was conducted on a treadmill with an intensity of 80-100% of maximum oxygen consumption and a moderate intensity program with intensity 65-70% of maximal oxygen consumption, 5 sessions per week for 6 weeks. Then, 48 hours after the last exercise session, the liver tissue was isolated on ice and kept at -80 ° C until the test. The supernatant was used to determine the activity of superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) enzymes as an antioxidant state for liver tissue homogenization. One-way analysis of variance was used to determine the difference between groups (P <0.05).

Superoxide dismutase enzyme (SOD) and glutathione peroxidase (GPX) were increased significantly in the continuous (P=0.002, P=0.005 respectively) and interval training (P=0.001) groups compared to control group. Catalase was increased significantly in the interval training group compared to the control group (P=0.015).

In general, continuous and interval training increase the level of antioxidant enzymes in old male rats and this increase was more pronounced in high intensity interval training group.