The comprehensive pathophysiological changes in a novel rat model of postinflammatory visceral hypersensitivity

So far, a comprehensive animal model that can mimic both the central and peripheral pathophysiological changes of irritable bowel syndrome (IBS) is lacking. Here, we developed a novel IBS rat model combining trinitro-benzene-sulfonic acid (TNBS) and chronic unpredictable mild stress (CUMS) (designated as TC-IBS) and compared it with the TNBS-induced and CUMS-induced models. TC-IBS showed a pronounced depression phenotype with increased corticotropin-releasing hormone receptor (CRHR)1 and CRHR2 expression at the frontal cortex and increased serum ACTH concentration. Visceral hypersensitivity (VH), as evidenced by colorectal distention (CRD) test, was highest in TC-IBS, accompanied by increased serum 5-hydroxytryptamine (5-HT) level and colonic 5-HT receptor 3A (5-HT_3AR)/5-HT receptor 2B expression, impaired tight junction protein expression including occludin, zonula occludens-1, and phosphorylated myosin light chain. Palonosetron, a second generation of 5-HT_3AR antagonist, alleviated VH significantly in TC-IBS. 16S rRNA sequencing showed that TNBS plus CUMS induced a significant disturbance of the gut microbiota. Cytokine profile analysis of TC-IBS model indicated an innate immune activation both in serum and colonic mucosa. Further, fecal microbiota transplantation improved VH and some pathophysiological changes in TC-IBS. In summary, we established a postinflammatory IBS model covering multifactorial pathophysiological changes, which may help to develop therapies that target specific IBS subtype.-Ma, J., Li, J., Qian, M., He, N., Cao, Y., Liu, Y., Wu, K., He, S. The comprehensive pathophysiological changes in a novel rat model of postinflammatory visceral hypersensitivity.