Relationship between the Extent of DNA Damage and Gastritis in Normal and Helicobacter pylori-Infected Patients

BACKGROUND/AIMS The role of Helicobacter pylori in gastric carcinogenesis is unclear, but H. pylori infection is thought to predispose carriers to gastric cancer. The aim of this study was to investigate the relationship between the extent of DNA damage in normal gastric epithelial cells and H. pylori-positive and -negative gastritis according to histological diagnosis. We also compared the percentage of cometed cells on the surface of the gastric epithelial cells to the percentage beneath the gastric mucosal cells using serial incubations times. METHODS The comet assay is a rapid, efficient and reproducible measure of DNA damage in single cell and it was used in this study. DNA damage was evaluated in 52 cases using alkaline single cell gel electrophoresis (comet assay). Comparisons were made between 19 normal individuals, 19 patients with H. pylori-positive and -negative gastritis and 14 mixed cases with different histology gradings to determine if there was a relationship between histological diagnosis and DNA damage (comet percentage). RESULTS The comet percentages in specimens from cases with normal histology were significantly higher than the comet percentages in specimens from cases with H. pylori-positive gastritis. In addition, there was a significant increase in the percentage of cometed cells on the surface of gastric epithelial cells in both normal and H. pylori-infected cells compared to the subsequent gastric cell layers of the same specimen. CONCLUSIONS A relationship between the comet percentage and the histological diagnosis was observed.