Brain and lungs of rats are differently affected by cigarette smoke exposure: Antioxidant effect of an organoselenium compound

Cigarette smoke exposure has been associated with oxidative stress in several organs. Antioxidant effect of diphenyl diselenide (PhSe)₂, an organoselenium compound, on oxidative damage induced by sub-chronic cigarette smoke exposure in brain and lungs of rats was investigated. Animals were exposed 5 times/week to one, two, three and four cigarettes for exposure periods of 15 min during the first, second, third and fourth weeks. Reactive species (RS) levels, enzymatic antioxidant defenses (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) activities) and non-enzymatic antioxidant defenses (ascorbic acid and non-protein thiol (NPSH) levels) were examined in brain and lungs of rats. An increase in RS levels induced by cigarette smoke in both tissues of rats was demonstrated. Cigarette smoke altered enzymatic antioxidant defenses (GST, CAT and SOD activities) in both tissues, and reduced the non-enzymatic antioxidant defenses in lungs. (PhSe)₂ (0.5 mg/kg/day, 5 times/week) restored RS levels and antioxidant defenses in brain of rats exposed to cigarette smoke. (PhSe)₂ treatment increased NPSH levels, GST and GR activities per se in lungs of rats. In conclusion, sub-chronic exposure to cigarette smoke caused alterations in antioxidant defense system and a tissue-specific oxidative stress in brain and lungs of rats. (PhSe)₂ restored antioxidant defenses in lungs and brain of rats.