Changes in the Expression and Distribution of Claudins, Increased Epithelial Apoptosis, and a Mannan-Binding Lectin-Associated Immune Response Lead to Barrier Dysfunction in Dextran Sodium Sulfate-Induced Rat Colitis

Background/Aims: This animal study aimed to define the underlying cellular mechanisms of intestinal barrier dysfunction. Methods: Rats were fed 4% with dextran sodium sulfate (DSS) to induce experimental colitis. We analyzed the sugars in 24-hour urine output by high pressure liquid chromatography. The expression of claudins, mannan-binding lectin (MBL), and MBL-associated serine proteases 2 (MASP-2) were detected in the colonic mucosa by immunohistochemistry, and apoptotic cells in the colonic epithelium were detected by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling method assay. Results: The lactulose and sucralose excretion levels in the urine of rats with DSS-induced colitis were significantly higher than those in the control rats. Mannitol excretion was lower and lactulose/ mannitol ratios and sucralose/mannitol ratios were significantly increased compared with those in the control group (p