OBJECTIVE: The aim of this study is to verify if oxidative stress is related to changes in content and pattern of β-catenin protein expression in an experimental model of diversion colitis. METHODS: Sixty Wistar rats were submitted to intestinal bypass. The animals were divided into three groups according to the sacrifice to take place in six, 12 and 18 weeks. For each group, five animals only underwent laparotomy (control). The presence of colitis was diagnosed by histological study, and its severity, by inflammation grading scale. Cellular oxidative stress was measured by comet assay. Tissue expression of β-catenin protein was analyzed by the immunohistochemistry and quantification of its tissue content by computerized morphometry. Statistical analysis was performed with the Student's t-test, median, Mann-Whitney, ANOVA and Kruskal-Wallis, adopting a significance level of 5% (p <0.05). RESULTS: Colon segments without fecal stream developed colitis, which worsened with time of exclusion. Segments without fecal stream suffer higher levels of oxidative stress when compared to those with stream, and it worsens with time of exclusion. The levels of cellular oxidative stress are directly related to the degree of inflammation. The total content of β-catenin in segments without fecal stream reduces after six weeks, and does not vary thereafter. The content of β-catenin in the apical portion of the colon crypts decreases with time, whereas in the basal region, it increases. The total content of β-catenin is inversely related to the degree of inflammation and levels of tissue oxidative stress levels. CONCLUSION: There are changes in tissue content of E-cadherin and increased expression of β-catenin in proliferative regions of colonic crypts, related with oxidative tissue stress.
colon; colitis; oxidative stress; adherens junctions; cell adhesion molecules; catenins; comet assay; immunohistochemistry; fatty acids, volatile; rats
