[Antioxidant enzyme activity in the gastric mucosa in precancerous conditions]

The primary defense against oxidation damage of tissues are anti-oxidant enzymes, e.g. superoxide dismutase, catalase and glutathione peroxidase. Some non-enzymatic substances have a significant anti-oxidant action (e.g. vitamin C, E, beta-carotene and others). The objective of the present work was to follow up the Cu/Zn superoxide dismutase activity, catalase and glutathione peroxidase (anti-oxidant enzymes of the gastric mucosa) in subjects with the risk of developing gastric cancer, e.g. those suffering from atrophic gastritis, hyperplastic polyps and gastric adenoma.

The authors examined 80 subjects (50 men and 30 women) aged 25 - 71 years. In all during endoscopic examination bioptic specimens of the mucosa were taken at standard sites of the gastric corpus and antrum for histological and enzymological examination. Enzymological examination: activity of Cu/Zn-superoxide dismutase (Randox Lab. Ltd. GB kit), catalase activity (modified method of Cavarocchia et al.) and glutathione peroxidase activity (method according to Paglia and Valentine). The Cu/Zn-superoxide dismutase activity was elevated in the group of patients with gastritis after gastrectomy (67%) and with gastric adenoma (35%), the catalase activity in patients with gastritis after gastrectomy (40%) and the glutathione peroxidase activity in patients with the diagnosis of gastritis after gastrectomy (185%), atrophic gastritis (46%) hyperplastic polyp (50%) and gastric adenoma (50%).

The increased activity of anti-oxidant enzymes was due to a higher concentration of the superoxide anion radical, hydrogen peroxide and organic peroxides (lipoperoxides); the source of active types of oxygen are phagocytic leucocytes in the chronically inflamed gastric mucosa.