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Oxidative damage and antioxidant status in the lungs and bronchoalveolar lavage fluid of rats exposed chronically to cigarette smoke.

The effect of chronic smoke exposure on oxidative damage and antioxidant status was studied in rats. Ten-week-old female Sprague-Dawley rats were exposed to fresh mainstream cigarette smoke or filtered room air twice daily, or maintained as room controls, for 65 weeks. Animals were sacrificed 18-20 hours after the last treatment. The bronchoalveolar lavage (BAL) fluid, lung tissues, and plasma were processed to assess oxidative damage and antioxidant status. Compared with sham and room control groups, the levels of conjugated dienes and alpha-tocopheryl quinone were significantly higher in the lung tissues of rats exposed to cigarette smoke. The levels of malondialdehyde, protein carbonyls, reduced glutathione (GSH), ascorbic acid and vitamin E, and activities of catalase and GSH peroxidase in the lung tissues were not significantly altered by smoke exposure. No significant differences in any measurements were found in BAL fluid and plasma among the experimental groups. The results obtained support the view that cigarette smoking increases oxidative stress and suggest a metabolic adaptation of antioxidant systems following chronic smoke exposure.