A RAT MODEL OF CHRONIC HELICOBACTER-PYLORI INFECTION - STUDIES OF EPITHELIAL-CELL TURNOVER AND GASTRIC-ULCER HEALING

Background: Our aim was to infect rats with Helicobacter pylori and to study the effects of the infection on the gastric mucosa in normal an d in ulcer-operated rats. Methods: A mouse-adapted H., pylori (cagA(-) , VacA(-)) strain was inoculated into 23 rats. Another 20 uninfected r ats served as controls. Two months later a gastric ulcer was induced i n some rats. The animals were killed 3, 6, or 15 days after the ulcer operation. Tissues were taken for histology and for culture of H. pylo ri. Serum antibodies were determined. Results: All inoculated rats wer e infected by H. pylori after 2 months, mainly in the antrum. In these rats a mild to moderate chronic inflammation and a significantly incr eased frequency of apoptotic cells were observed in the antrum and in the ulcer margin, the ulcer healing was delayed, and the serum level o f H. pylori-specific Ig was increased. Conclusions: H. pylori infectio n in rats was successful and was accompanied by a mild to moderate muc osal inflammation. Gastric ulcer healing was delayed in infected rats, probably due to the inflammation and the increased apoptosis in epith elium.