Objective:To explore the effect of regular aerobic exercise on oxidative stress, inflammatory reaction and apoptosis with a rat model of colitis.Methods:Forty-five C57BL/6 mice were randomly divided into a control group, a model group and a model exercise group, each of 15. Colitis was induced in the rats of the model and model exercise groups through administration of 3.5% sodium dextran sulfate. The control group and the model group were kept quiet in their cages, while the model exercise group performed voluntary wheel running for 8 weeks after the successful modelling. Any histopathological changes in the colon tissue were observed after hematoxylin and eosin staining. Oxidative stress, inflammatory reaction and apoptosis were measured from colon tissue homogenates.Results:Compared with the control group, the average expression of the tumor necrosis factor α (TNF-α), interleukin (IL)-1β, IL-6 and prostaglandin E2 (PGE2) as well as levels of reactive oxygen species (ROS), malondialdehyde (MDA) and nitric oxide (NO) and inducible nitric oxide synthase (iNOS) and Caspase-3 activity and the protein expression of cyclooxygenase 2 (COX2), nuclear factor kappa B (NF-κB) p65, apoptosis inducing factor (AIF), cytochrome c (Cyt C) and Bax had all increased significantly in the other two groups, while the levels of IL-10 and glutathione (GSH), the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) and the protein expression of Bcl-2 protein had decreased significantly in the model group. Compared with the model group, the average content of TNF-α, IL-1 β, IL-6, PGE2, ROS, MDA and NO, the activity of iNOS and Caspase-3 and the protein expression of COX2, NF-κB p65, AIF, CytC and Bax had decreased significantly, while that of IL-10 and GSH, the activity of SOD and GPx and the protein expression of Bcl-2 protein had increased significantly in the model exercise group.Conclusion:Regular aerobic exercise has a protective effect against colitis through improving oxidative stress, inflammation and apoptosis, at least in rats.