Effectiveness of different exercise on antioxidant: a meta-analysis

Objective: To evaluate the protective effects of exercise on oxidative damage, which provides reference for revealing the mechanism of different exercise anti-oxidative damage by activating the Nrf2 signaling pathway.Methods: Literature were searched on the databases Web of Science, Cochrane, PubMed, EMBASE, China National Knowledge Infrastructure, VIP, Wan fang data, CBM to search for the data of exercise intervention on rats. Randomized controlled trials were included to compare exercise groups with control groups on relevant proteins about oxidative damage via Nrf2 Signaling Pathway. The quality of evidence and risk of bias were assessed using the GRADE system and the Cochrane Risk of Bias tool, respectively. Meta -analysis was also used, whenever possible. Two reviewers extracted the data independently. 39 eligible articles were included in this study, with a total of 781 rats.Results: The difference between groups was described by standard mean difference (SMD). Levels of ROS [SMD=5.22, 95% CI (1.82,8.62)], SOD [SMD=2.41 , 95% CI (1.12 , 3.69)], Nrf2 [SMD=1.51, 95% CI (0.55, 2.47)], NQO1 [SMD 1.25, 95% CI (0.56, 1.95)], HO-1 [SMD=1.83, 95% CI (0.64, 3.01)] in the exercise intervention group was higher than that in the control group (P<0. 05). Levels of GSH [SMD = 0.84, 95% CI (-3.48, 1.80)], MDA [SMD=0, 95% CI (-1.02, 1.03)]. There is no significant difference of the two results (GSH, MDA) in the exercise intervention group compared with the control group (P>0.05). Subgroup analysis demonstrated that aerobic exercise increases the expression of Nrf2 significantly (P<0.00001). The effect of resistance exercise on Nrf2 is not significant.Conclusion: Exercise can play an antioxidant role by activating the Nrf2 signaling pathway. Aerobic exercise and exercise intervention for >= 8 weeks significantly increased Nrf2 expression, resistance exercise and exercise intervention for <8 weeks had no significant effect on Nrf2 expression, and exhaustive exercise significantly decreased Nrf2 expression.