EVALUATION OF METHYLENE-BLUE AND TRIPLE THERAPY FOR ERADICATION OF HELICOBACTER-PYLORI INFECTION IN THE NUDE-MOUSE MODEL

Objective: To determine how far Helicobacter pylori infection can be eradicated with methylene blue and triple therapy (amoxicillin, metronidazole, bismuth subnitrate), using a nude mouse model. Methods: Four weeks after inoculation of H. pylori into the stomach, two groups of nude mice were administered methylene blue or triple therapy via the stomach for 1 week. A control group of nude mice was given culture fluid alone after the inoculation. The number of H. pylori and histological changes in the stomach were determined weekly for 5 weeks, starting from the completion of drug administration. Results: In the methylene blue treatment group, the concentration of H. pylori was significantly reduced for 1-3 weeks after treatment compared with the control group. In the triple therapy group, the concentration of H. pylori was significantly reduced until the end of the study (5 weeks), starting immediately after drug administration, compared with the control group. Histologically, the formation of erosions in the methylene blue treatment group was slightly less than that of the control group for 1-4 weeks after the drug treatment. Infiltration of mononuclear cells into the submucosal layer in the treatment group was slightly less than that of the control group in the 4th week. The histological changes in the triple therapy group were similar to those of the methylene blue treatment group. Conclusion: The nude mouse model is useful in studying the treatment of human H. pylori-associated gastroduodenal diseases.