Figure 1.

Disease progression during Helicobacter felis infection in C57BL/6 mice. (A) Histological scores of H. felis infected B6 stomachs postinfection. *p<0.05 compared with B6 mock controls. (B) Colonization scores over the course of the infection. *p<0.05 compared with 4-week B6 H. felis–infected stomachs. In these two graphs, the horizontal line represents the median score, and the circles represent individual animals and indicate the numbers of animals used in the experiments in this study. Representative hematoxylin–eosin stains of infected stomachs over time are shown in C–G. (C) A mock-infected mouse showing the normal glandular structure of the stomach (histologic score 0). (D) Four weeks postinfection the stomach shows significant gastritis while maintaining normal gastric glandular architecture (histologic score = 4). (E) A stomach infected for 16 weeks shows significant gastric atrophy, whereas a 52-week infected animal shows intestinal metaplasia (histologic scores of 8 and 9, respectively) (F). (G) A 52-week infected stomach that has gastric carcinoma in situ, as indicated by the invasion of the abnormal gastric glands through the muscularis layer (histologic score = 9). Periodic acid-Schiff (PAS) stains of infected stomachs over time are shown in H–L. The mock-infected shows the normal magenta-stained neutral mucus distribution of the stomach (H). These neutral mucins are not significantly altered 4 weeks after infection (I) but are lost as the infection proceeds and dysplasia and gastric adenocarcinoma develop (J–L). Bar = 50 μm.