Exposure to alcohol and tobacco smoke causes oxidative stress in rats

Background: Tobacco smoking and alcohol abuse causes oxidative stress in humans and underlay numerous chronic degenerative diseases. Liver is the main organ exposed to alcohol toxic metabolites, whereas tobacco smoke is chiefly harmful to the lungs. Methods: The aim of the current study was the assessment and comparison of selected oxidative stress markers, reduced glutatione (GSH), glutathione S-transferase (GST), superoxide dismutase (SOD), catalase, nitrites and protein nitrosylation and DNA damage in the livers and in the lungs of alcohol-addicted rats exposed to tobacco smoke alone or in combination with a single dose of ethanol. Results: The highest levels of GSH were measured in the liver of smoke only exposed animals and in the lungs of rats exposed to smoke and alcohol. In the liver of animals treated with a single dose of alcohol or with smoke and alcohol, GST was significantly higher than in the group exposed to smoke only. SOD and catalase showed the highest activities in the livers of rats receiving a single dose of alcohol. High concentration of nitrites was observed in the lungs of animals treated with smoke and alcohol in combination, which corresponded to elevated protein nitrosylation in this group, whereas in the livers of these animals relatively low level of nitrites was accompanied with the lowest concentration of nitrosylated proteins. In the liver of alcohol only treated rats the highest nitrites corresponded to the highest protein nitrosylation. In the lungs of all treatment groups the range of DNA damage was higher, than the respective values in the livers. Although alcohol is not considered a specific toxicant to the lungs it was found to cause oxidative stress in this organ. Conclusions: The obtained results suggest that in the ethanol-addicted rats combined exposure to smoke and alcohol differentially modulate endogenous antioxidant defense system and reactions to oxidative stress.