Oxidative damage of chronic PM2.5 exposure to rat lung tissue

Objective:To investigate the oxidative damage caused by chronic exposure to PM2.5 in rat lung tissues according to the PM2.5 concentration in the atmospheric environment.Methods:Forty healthy SD rats were randomly divided into 4 groups,the control group and the 5 mg/kg,10 mg/kg,20 mg/kg PM2.5 exposure groups.The rats in each group were administered by intratracheal instillation with 1ml/kg,2 times per week.After 8 weeks of exposure,the changes of lung histopathology,superoxide dismutase(SOD),malondialdehyde(MDA),catalase(CAT)and reduced glutathione/oxidized glutathione(GSH/GSSG)were detected.Results:Compared with the control group,the histopathological changes in the lung tissue of the three dose groups exposed to PM2.5 were significant.Masson staining showed obvious collagen fibrosis.The activities of SOD and CAT in the lung tissue of the exposed group were decreased,and the contents of MDA were increased with statistically significant(P<0.05),showing that the difference was the most obvious in the middle-dose group.The GSH/GSSG ratio in the lung tissue decreased,indicating that the degree of oxidative damage was aggravated.Conclusion:Chronic exposure to PM2.5 could induce oxidative stress in the lung tissue of rats and caused different degrees of oxidative damage.