| Background and Aims:Inflammatory bowel disease(IBD),comprising Crohn’s disease(CD)and ulcerative colitis(UC),is a chronic inflammatory disorder characterized by chronic uncontrolled mucosal inflammation leading to chronic diarrhoea and abdominal pain and occurring in genetically susceptible individuals exposed to environmental factors.The purpose of this study is to investigate expression and localization of tight junction protein claudin-1,claudin-2 and claudin-4and evaluate the significance of these levels on etiology of the intestinal tight junction barrier in UC disease states and find therapeutic strategies to promote restoration.Methods:This work was conducted on 40 Wister rats equally divided into 2groups as normal control group and oxazolone-induced colitis group.20 Wister rats received 7.5mg/ml oxazolone rectally.Colon samples were used to analyze tight junction proteins by immunohistochemistry,western blot and real-time polymerase chain reaction.Enzyme Linked Immunosorbent Assay was performed on rat serum and colon tissuse to assess inflammatory factor levels.Results:The DAI and histopathological inflammation score of the oxazolone-induced colitis group were significantly greater compared with those of the control group(P<0.05).The expressions of IL-4 and IL-5 in colon tissue and serum were significantly increased(P<0.05).A significant increase was observed in claudin-2 levels in oxazolone-induced colitis group(P<0.05).However,the expression levels of claudin-1 and claudin-4 in the colonic tissue were significantly lower in the oxazolone-induced colitis group compared with those in the control group(P<0.05).Conclusion:Intestinal barrier dysfunction is a main feature of the UC.Particularly the changes of tight junction protein claudin-1,-2,-4 expression were found in colon samples of active UC and was suggested to contribute to impaired epithelial barrier.This characteristic may have potential applicability for prognostic,diagnostic and therapeutic approaches. |
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