Acute and chronic histological changes of the small bowel secondary to C. jejuni infection in a rat model for post-infectious IBS.

Background: Campylobacter jejuni has been implicated in the pathogenesis of post-infectious irritable bowel syndrome (PI-IBS) in humans, effects which may be because of cytolethal distending toxin (CDT). In this study, we characterized both acute and chronic-phase histological changes of the small bowel in rats exposed to wild-type C. jejuni 81-176, or a strain that does not produce CDT, by using a validated rat model of PI-IBS.

Methods: Sprague-Dawley rats were given 1.0 × 10(8) CFU of either wild-type C. jejuni 81-176 (C+, PI/C+) or the CDT-negative strain (CDT-), or vehicle alone (Control). Acute-phase rats (C+, CDT-) were euthanized on days 2, 4, 8, 16, and 32. Chronic-phase rats (PI/C+, Control) were euthanized 3 months after clearing the initial infection. Segments of duodenum, jejunum, and ileum were resected and the contents plated for C. jejuni culture, and tissue sections were stained for histology.

Results: We observed preferential infection of the ileum and jejunum by Campylobacter jejuni. Compared with controls, epithelial cell basal membrane ballooning, villous tip disruption, and reduced villous-to-crypt ratios were observed for both C+ and CDT- rats. Villous widening, the only result significantly different in C+ vs. CDT- rats, was greatest at day 4 (134.1 ± 21.12 μm vs. 109.9 ± 10.6 μm for CDT-, P < 0.01). Little or no cellular inflammatory changes were seen during acute C. jejuni infection. Three months after clearing the initial infection, no histological changes remained.

Conclusion: Significant histological changes, with the absence of inflammatory cells, are seen in the duodenum, jejunum, and ileum of rats during acute infection with C. jejuni. These changes occurred irrespective of the presence or absence of the CDT toxin.