Physical exercise is effective in preventing cigarette smoke-induced pulmonary oxidative response in mice

Reactive oxygen species (ROS) are important in the pathogenesis of pulmonary injury induced by cigarette smoke (CS) exposure, and physical exercise (Ex) is useful in combating impaired oxidative process. We verified the preventive effects of Ex on lung oxidative markers induced by smoking. In this study, 36 mice (C57BL-6, 30-35 g) were split into four groups: control, CS, Ex, and CS plus Ex. Ex groups were given prior physical training in water (2×30 min/d, 5 days/wk, 8 weeks). After training, the CS groups were subjected to passive exposure to four cigarettes, 3 × per day, for 60 consecutive days. After 24 hours from the last exposure, CS animals were sacrificed, and lung samples were collected for further analysis. Left lung sample was prepared for histological analysis, and right lung was used for biochemical analysis (superoxide, hydroxyproline, lipid peroxidation [thiobarbituric acid reactive species], protein carbonylation [carbonyl groups formation], superoxide dismutase [SOD], catalase [CAT], and glutathione peroxidase [GPx] activities). Group comparisons were evaluated by analysis of variance (ANOVA). Results were expressed as mean ± standard deviation, with P<0.05 considered significantly different. Preventive Ex impeded histological changes and increased the enzymatic defense system (SOD and GPx) by reducing oxidative damage in lipids and proteins. This preventive effect of prior physical Ex alleviates damage caused by CS exposure.