[Development of mouse and rat model of Helicobacter pylori infection]

To develop different rodent model of H. pylori infection as to meet different requirement for different purpose of study.

40 two-grade Wistar rats, 40 two-grade C57BL/6 mice and 40 SPF BALB/c mice were randomly divided into two groups: experimental and control groups. Animals in the experimental group were inoculated orally Hp strain (Sydney Strain 1, SS1), 0.4 ml of inoculum per mouse, 1.5 ml per rat (10(9) organisms/ml) five times for a week. In 4, 8, 12 and 24 weeks after the last bacteria inoculum, 5 animals in the experimental and control groups were sacrificed respectively. Histology and Hp colonization were assessed by HE staining, Gimesa staining, Urease test, and Hp culture.

In 4 weeks, in all experimental animals bacteria were clearly visible at antrum and body, but the number of Hp colonization varied according to the animal strain. Heavy colonization was seen in C57BL/6 in antrum and body, and in BALB/c and Wistar colonization was located mainly at antrum, less at body, which tended to increase over the experiment time, especially in Wistar. Hp was negative in the controls. All animals had no inflammatory changes in 4 weeks, however, in 8, 12 and 24 weeks in Balb/c. Wistar and C57BL/6 of the experimental group, mild to moderate chronic active gastritis was observed in antrum and body, which increased in severity over time, atrophy gastritis was still not seen in 24 weeks. In contrast, in the controls, no remarkable changes were detected.

SS1 Hp can colonize in the glandular stomach mucosa of BALB/c, C57BL/6 mice and Wistar rats and leads to chronic active gastritis in long-term study. SS1 mouse and rat model is adaptable for animal experimentation of H. pylori including vaccine studies, screening for novel therapeutics and investigation of mechanisms of pathogenesis.