Abstract

Smoking elevates risk of peptic ulcer and gastrointestinal cancer in human being. In this study, the severity of the damage was assessed by detection of nitric oxide levels, oxidative stress of gastric juice in smokers and non-smokers. 43 smoker patients with active peptic ulcer as case group and 43 non-smokers without peptic ulcer, 43 smokers without peptic ulcer and 43 non-smokers with active peptic ulcer as control groups were selected for this study. The levels of nitric oxide in gastric juice and the rate of DNA damage, those of total antioxidant capacity and the activities of superoxide dismutase and glutathione peroxidase in gastric mucosa were determined using standard methods. The rate of DNA damage in case group was significantly higher than those of controls groups. Comparing with two control groups, increase in nitric oxide levels of case group was noticed. Comparing with control group, significant elevation in the mean activities of superoxide dismutase and glutathione peroxidase was observed in the case group. Total antioxidant capacities of control groups were higher than that of case group. Results of the study shows that damage rate of DNA have a direct correlation with the presence of toxic agents in cigarette smoke and tar especially NO^o. Increase in activity of antioxidant enzymes, superoxide dismutase and glutathione peroxidase, and decrease in total antioxidant capacity in gastric juice; confirm the presence of oxidative stress in smokers' gastric juice.

Key words: Cigarette smoking, DNA damage, oxidative and nitrosative stress, nitric oxide, dyspepsia.