RESUMO
BACKGROUND: In murine Helicobacter infection it has been demonstrated that the degree of gastric mucosal inflammation is determined by mouse strain. This is a valuable tool for investigating genetic, immunological or bacterial determinants for the outcome of human Helicobacter infection. This study aims to devise a robust method to facilitate these investigations. MATERIALS AND METHODS: C57BL/6, BALB/c and (C57BL/6 x BALB/c) F1 mice were given 10(8)H. felis by gavage on days 1, 3 and 5 of the experiment Sections of the lesser and greater curve of stomach were examined at 12 weeks to assess active gastritis using a semi-quantitative and a quantitative method by counting neutrophils in glands in four zones of the mucosa. RESULTS: Semi-quantitative scoring for active inflammation, based on the Sydney System, was inadequate with little discrimination between strains. Quantifying the level of active inflammation, counting the number of neutrophils in inflamed gastric glands and taking the total number of neutrophils in three inflamed pits within each zone (cardia, body, transitional zone and antrum) showed clear differences between the two parental strains for the degree of active gastritis and furthermore, using this system the phenotype of the (C57BL/6 x BALB/c) F1 was found to be between the two parental extremes. CONCLUSIONS: This novel method provides a numerical value for active inflammation in the stomach that is accurate, reproducible and discriminatory.