ICC density predicts bacterial overgrowth in a rat model of post-infectious IBS

To investigate the interstitial cells of Cajal (ICC) number using a new rat model.Sprague-Dawley rats were assigned to two groups. The first group received gavage with Campylobacter jejuni (C. jejuni) 81-176. The second group was gavaged with placebo. Three months after clearance of Campylobacter from the stool, precise segments of duodenum, jejunum, and ileum were ligated in self-contained loops of bowel that were preserved in anaerobic bags. Deep muscular plexus ICC (DMP-ICC) were quantified by two blinded readers assessing the tissue in a random, coded order. The number of ICC per villus was compared among controls, Campylobacter recovered rats without small intestinal bacterial overgrowth (SIBO), and Campylobacter recovered rats with SIBO.Three months after recovery, 27% of rats gavaged with C. jejuni had SIBO. The rats with SIBO had a lower number of DMP-ICC than controls in the jejunum and ileum. Additionally there appeared to be a density threshold of 0.12 DMP-ICC/villus that was associated with SIBO. If ileal density of DMP-ICC was0.12 ICC/villus, 54% of rats had SIBO compared to 9% among ileal sections with0.12 (P0.05). If the density of ICC was0.12 DMP-ICC/villus in more than one location of the bowel, 88% of these had SIBO compared to 6% in those who did not (P0.001).In this post-infectious rat model, the development of SIBO appears to be associated with a reduction in DMP-ICC. Further study of this rat model might help understand the pathophysiology of post-infectious irritable bowel syndrome.