Article ID Journal Published Year Pages File Type
5897068 Cytokine 2015 10 Pages PDF
Abstract

•Colitis manifests with diarrhea, hypoproteinemia and malabsorption of nutrients.•A novel model of localized colonic injury induced by bipolar electro-cautery has been described.•In this model, up-regulation of proinflammatory cytokines protein and mRNA occurs in the whole gut.•A decreased jejunal amino acid absorption swiftly follows localized colonic injury.•The spreading effects of colitis to non-inflamed intestines may involve neuro-humoral pathways.

BackgroundColitis is associated with functional abnormalities in proximal non-inflamed gut areas, but animal models to study small bowel dysfunction in colitis have limitations. This study aims to determine small intestinal alanine absorption and cytokine expression in a novel model of colonic ulceration induced by electro-cautery.MethodsA descending colon ulcer was induced in rats by a bipolar electro-cautery probe. Ulcer score was determined using Satoh's criteria. Jejunal alanine absorption was measured immediately and at different time intervals post ulcer induction. Levels of interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) protein and m-RNA were determined in mucosal scrapings obtained from the colon, duodenum, jejunum and ileum at various time intervals after colonic ulcer induction.ResultsThe mean ulcer score was 3 up to 48 h, followed by healing by 96 h post ulcer induction. Small bowel histology was normal throughout. Jejunal alanine absorption was reduced by 12-34% immediately and up to 72 h after cautery and returned to normal at 96 h. IL-1 and TNF-α mRNA increased significantly in the colon, duodenum, jejunum and ileum 3 h post electro-cautery and returned to normal at 48 h, while that of IL-6 increased significantly at 48 h post ulcer induction. Similarly, IL-1, IL-6 and TNF-α protein levels increased in the duodenum, jejunum, ileum and colon up to 48 h post ulcer induction.ConclusionsElectrically induced localized colonic injury increased production of pro-inflammatory cytokines in non-inflamed segments of the small intestine and was associated with derangements of jejunal absorptive function.

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