Helicobacter pylori infection causes different clinical and pathological symptoms in human, such as chronic gastritis, peptic ulcer and gastric neoplasia. In this study, nitric oxide levels and activity of superoxide dismutase and glutathione peroxidase were examined to study the oxidative stress in H.Pylori infection.

43 patients infected with H.Pylori (18 males and 25 females), with the average age of 65/1 ± 74/44 years old, were selected as the treatment group, and 43 uninfected individuals (19 males and 24 females) with the average age of 47/1 ± 20/43 years old, as the control group.

The level of nitric oxide in gastric juice (gastric juice nitric oxide) was assessed by colorimetric Griess method, and the level of gastric mucosal superoxide dismutase and glutathione peroxidase enzymes activities were measured by colorimetric method.

The mean of nitric oxide level in the treatment group compared with the control group showed a significant decrease (p = .0001). The mean activity of superoxide dismutase enzyme and glutathione peroxidase enzyme in treatment group revealed a significantly decrease in comparison with that of the control group (p = .0001, in both).

In correlation coefficient test, a significantly inverse relationship was observed between the level of nitric oxide in gastric juice and the level of Gastric mucosal superoxide dismutase activity (superoxide dismutase enzyme activity of gastric mucosa) (r = -.355 and p = .023) It seems that H.Pylori, through making a change in the nature of nitric oxide in gastric juice, not only protect the bacteria but also may cause nitrosative stress in gastric juice, and also bring about an increase in oxidative stress in the stomach tissue.