Study Of The Correlation Between Interferon-γand Tight Junction Proteins Of Colonic Mucosa In Patients With Ulcerative Colitis

Objective:Ulcerative colitis (UC) is a chronic non-specific inflammatory disease involving the rectum and colon mucosa. It’s etiology and pathogenesis has not yet entirely clear.There is also not completely targeted therapy. Large amounts of evidence have suggested that the immune abnormalities regulated by cytokines, such as interferon-γ (IFN-γ), have played a very important role in the pathogenesis of UC. At the same time, barrier dysfunction caused by aberrant epithelial barrier structure have been found in patients’ colonic mucosa of UC. In order to analyze the correlation of IFN-γ and the expression of tight junction protein and the clinicopathologic features of UC, we detect the expression of IFN-γ, tight junction protein occludin and zo-1and its genes OCLN and ZO-1of colonic mucosa in UC patients, to explore whether there is an association between IFN-γ and the pathogenesis of UC, and provide experimental basis for the search for new therapeutic targets.Materials and Methods:A total of60subjects were divided into UC group (n=40) and control group (n=20). The expressions of gene OCLN and ZO-1were detected by real-time fluorescent quantitative reversed transcriptive PCR (Real-time qRT-PCR). And the expressions of tight junction proteins occludin and zo-1were detected by immunohistochemical staining.Results:1Expression of IFN-γThe expression of IFN-γ in UC group was significantly higher compared with control group(P<0.01). And the expression of IFN-γ of the severe group was significantly higher compared with the other three groups with DAI (P<0.01).But there was no statistical significant differences of the expressions of IFN-γ between different groups of histological grade (P>0.05).2Expressions of gene OCLN and ZO-1The expressions of gene OCLN and ZO-1in UC group were significantly lower compared with control group(P<0.01). There were no statistical significant differences of the expressions of gene OCLN and ZO-1between different groups of age, sex, disease activity index (DAI) and histological grade (P>0.05).3Expressions of protein occludin and zo-1The expressions of protein occludin and zo-1in UC group were significantly lower compared with control group(P<0.05). There were no statistical significant differences of the expressions of protein occludin and zo-1between different groups of DAI and histological grade (P>0.05).4Correlation of IFN-γ and gene OCLN and ZO-1and protein occludin and zo-1In UC, there was a negative correlation of IFN-γ and the expressions of protein occludin and zo-1and their gene OCLN and ZO-1.And the correlation coefficients are-0.298,-0.325,-0.794,-0.820respectively (P<0.05).Conclusions:1The expressions of protein occludin and zo-1and their gene OCLN and ZO-1in UC group were lower compared with control group. The result suggested that the dysfunction of the intestinal barrier function was caused by the decreased expression of the tight junction proteins, which played an important role in the pathogenesis of UC.2The expression of IFN-γ in UC group was significantly higher compared with control group. And with the increase of disease activity, the expression of IFN-y was significantly higher in UC group. The result suggested that IFN-γ was involved with the pathogenesis and severity of UC.3In UC, there was a negative correlation of IFN-γ and the expressions of protein occludin and zo-1and their gene OCLN and ZO-1, which suggested that, for IFN-γ, the probable pathogenesis of UC was the dysfunction of the intestinal barrier function caused by the decreased expression of the tight junction proteins.