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.324343358Pravda, J., Radical induction theory of ulcerative colitis (2005) World J Gastroenterol, 11 (16), pp. 2371-2384Gaudier, E., Hoebler, C., Physiological role of mucins in the colonic barrier integrity (2006) Gastroenterol Clin Biol, 30 (8-9), pp. 965-974Laukoetter, M.G., Nava, P., Nusrat, A., Role of the intestinal barrier in inflammatory bowel disease (2008) World J Gastroenterol, 14 (3), pp. 401-407Berkes, J., Viswananthan, V.K., Savkovic, S.D., Hecht, G., Intestinal epithelial responses to enteric pathogens: Effects on the tight junction barrier, iron transport, and inflammation (2003) Gut, 52 (3), pp. 439-451Clayburgh, D.R., Shen, L., Turner, J.R., A porous defense: The leaky epithelial barrier in intestinal disease (2004) Lab Invest, 84 (3), pp. 282-291Usami, Y., Chiba, H., Nakayama, F., Ueda, J., Matsuda, Y., Sawada, N., Reduced expression of claudin-7 correlates with invasion and metastasis in squamous cell carcinoma of the esophagus (2006) Hum Pathol, 37 (5), pp. 569-577Gumbiner, B., Stevenson, B., Grimaldi, A., The role of the cell adhesion molecule uvomorulin in the formation and maintenance of the epithelial junctional complex (1988) J Cell Biol, 107 (4), pp. 1575-1587Gumbiner, B.M., McCrea, P.D., Catenins as mediators of the cytoplasmic functions of cadherins (1993) J Cell Sci Suppl, 17, pp. 155-158Yeager, M., Unger, V.M., Falk, M.M., Synthesis, assembly and structure of gap junction intercellular channels (1998) Curr Opin Struct Biol, 8 (6), pp. 810-811Hynes, R.O., Zhao, Q., The evolution of cell adhesion (2000) J Cell Biol, 150 (2), pp. F89-F96Kypta, R., Bernfield, M., Burridge, K., Geiger, B., Goodenough, D., Humphries, M., Hynes, R., Yurchenco, P., Junções celulares, adesão celular e matriz extracelular (2006) Biologia Molecular Da Célula, pp. 1065-1125. , In: Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P. (eds.), Porto Alegre: ARTMEDDemetter, P., de Vos, M., van Damme, N., Baeten, D., Elewaut, D., Vermeulen, S., Focal up-regulation of E-cadherin catenin complex in inflamed bowel mucosa but reduced expression in ulcer-associated cell lineage (2000) Am J Clin Pathol, 114 (3), pp. 364-370Aust, D.E., Terdiman, J.P., Willenbucher, R.F., Chew, K., Ferrell, L., Florendo, C., Altered distribution of β-catenin, and its binding proteins E-cadherin and APC, in ulcerative colitisrelated colorectal cancers (2001) Mod Pathol, 14 (1), pp. 29-39Kucharzik, T., Walsh, S.V., Chen, J., Parkos, C.A., Nusrat, A., Neutrophil transmigration in inflammatory bowel disease is associated with differential expression of epithelial intercellular junction proteins (2001) Am J Pathol, 159 (6), pp. 2001-2009Laukoetter, M.G., Nava, P., Nusrat, A., Role of the intestinal barrier in inflammatory bowel disease (2008) World J Gastroenterol, 14 (3), pp. 401-407Gassler, N., Rohr, C., Schneider, A., Kartenbeck, J., Bach, A., Obermüller, N., Inflammatory bowel disease is associated with changes of enterocytic junctions (2001) Am J Physiol Gastrointest Liver Physiol, 281 (1), pp. G216-G228Ozawa, M., Ringwald, M., Kemler, R., Uvomorulin-catenin complex formation is regulated by a specific domain in the cytoplasmic region of the cell adhesion molecule (1990) Proc Natl Acad Sci USA, 87 (11), pp. 4246-4250Schmitz, H., Barmeyer, C., Fromm, M., Runkel, N., Foss, H.D., Bentzel, C.J., Altered tight junction structure contributes to the impaired epithelial barrier function in ulcerative colitis (1999) Gastroenterology, 116 (2), pp. 301-309Takahashi, M., Fukuda, K., Sugimura, T., Wakabayashi, K., Beta-catenin is frequently mutated and demonstrates altered cellular localization in azoxymethane-induced rat colon tumors (1998) Cancer Res, 58 (1), pp. 42-46Parrish, A.R., Catania, J.M., Orozco, J., Gandolfi, A.J., Chemically induced oxidative stress disrupts the E-cadherin/catenin cell adhesion complex (1999) Toxicol Sci, 51 (1), pp. 80-86Meyer, T.N., Schwesinger, C., Ye, J., Denker, B.M., Nigam, S.K., Reassembly of the tight junction after oxidative stress depends on tyrosine kinase activity (2001) J Biol Chem, 276 (25), pp. 22048-22055Dorudi, S., Sheffield, J.P., Poulsom, R., Northover, J.M., Hart, I.R., E-cadherin expression in colorectal cancer. An immunocytochemical and in situ hybridization study (1998) Am J Pathol, 142 (4), pp. 981-986Chen, J., Huang, X.F., The signal pathways in azoxymethane induced colon cancer and preventive implications (2009) Cancer Biol Ther, 8 (14), pp. 1313-1317Jankowski, J.A., Bedford, F.K., Boulton, R.A., Cruickshank, N., Hall, C., Elder, J., Alterations in classical cadherins associated with progression in ulcerative and Crohn's colitis (1998) Lab Invest, 78 (9), pp. 1155-1167Hermiston, M.L., Gordon, J.I., Inflammatory bowel disease and adenomas in mice expressing a dominant negative N-cadherin (1995) Science, 270 (5239), pp. 1203-1207Karayiannakis, A.J., Syrigos, K.N., Efstathiou, J., Valizadeh, A., Noda, M., Playford, R.J., Expression of catenins and E-cadherin during epithelial restitution in inflammatory bowel disease (1998) J Pathol, 185 (4), pp. 413-418Nollet, F., Berx, G., van Roy, F., The role of the E-cadherin/ catenin adhesion complex in the development and progression of cancer (1999) Mol Cell Biol Res Commun, 2 (2), pp. 77-85Sheehan, J.F., Brynjolfsson, G., Ulcerative colitis following hydrogen peroxide enema: Case report and experimental production with transient emphysema of colonic wall and gas embolism (1960) Lab Invest, 9, pp. 150-168Marques, L.H.S., Silva, C.M.G., Lameiro, T.M.M., Almeida, M.G., Cunha, F.L., Pereira, J.A., Avaliação dos níveis de peroxidação lipídica em células da mucosa cólica após aplicação de enemas com peróxido de hidrogênio: Estudo experimental em ratos (2010) Rev Bras Colo-proctol, 30 (3), pp. 272-280Martinez, C.A., Ribeiro, M.L., Gambero, A., Miranda, D.D., Pereira, J.A., Nadal, S.R., The importance of oxygen free radicals in the etiopathogenesis of diversion colitis in rats (2010) Acta Cir Bras, 25 (5), pp. 387-395Longatti, T.S., Acedo, S.C., de Oliveira, C.C., Miranda, D.D., Priolli, D.G., Ribeiro, M.L., Inflammatory alterations in excluded colon in rats: A comparison with chemically induced colitis (2010) Scand J Gastroenterol, 45 (3), pp. 315-324Damiani, C.R., Benetton, C.A., Stoffel, C., Bardini, K.C., Cardoso, V.H., Di Giunta, G., Oxidative stress and metabolism in animal model of colitis induced by dextran sulfate sodium (2007) J Gastroenterol Hepatol, 22 (11), pp. 1846-1851Liu, Q., Shimoyama, T., Suzuki, K., Umeda, T., Nakaji, S., Sugawara, K., Effect of sodium butyrate on reactive oxygen species generation by human neutrophils (2001) Scand J Gastroenterol, 36 (7), pp. 744-750Glotzer, D.J., Glick, M.E., Goldman, H., Proctitis and colitis following diversion of the fecal stream (1981) Gastroenterology, 80 (3), pp. 438-441Agarwal, V.P., Schimmel, E.M., Diversion colitis: A nutritional deficiency syndrome? (1989) Nutr Rev, 47 (9), pp. 257-261Butzner, J.D., Parmar, R., Bell, C.J., Dalal, V., Butyrate enema therapy stimulates mucosal repair in experimental colitis in the rat (1996) Gut, 38 (4), pp. 568-573Nonose, R., Spadari, A.P., Priolli, D.G., Máximo, F.R., Pereira, J.A., Martinez, C.A., Tissue quantification of neutral and acid mucins in the mucosa of the colon with and without fecal stream in rats (2009) Acta Cir Bras, 24 (4), pp. 267-275Martinez, C.A., Nonose, R., Spadari, A.P., Máximo, F.R., Priolli, D.G., Pereira, J.A., Quantification by computerized morphometry of tissue levels of sulfomucins and sialomucins in diversion colitis in rats (2010) Acta Cir Bras, 25 (3), pp. 231-240Sousa, M.V., Priolli, D.G., Portes, A.V., Cardinalli, I.A., Pereira, J.A., Martinez, C.A., Evaluation by computerized morphometry of histopathological alterations of the colon wall in segments with and without intestinal transit in rats (2008) Acta Cir Bras, 23 (5), pp. 417-424Caltabiano, C., Máximo, F.R., Spadari, A.P., Miranda, D.D.C., Serra, M.M., Ribeiro, M.L., 5-aminosalicylic (5-ASA) can reduce the levels of oxidative DNA damage in cells of colonic mucosa with and without fecal stream (2011) Dig Dis Sci, 56 (4), pp. 1037-1046Gupta, R.B., Harpaz, N., Itzkowitz, S., Hossain, S., Matula, S., Kornbluth, A., Histologic inflammation is a risk factor for progression to colorectal neoplasia in ulcerative colitis: A cohort study (2007) Gastroenterology, 133 (4), pp. 1099-1105Ribeiro, M.L., Priolli, D.G., Miranda, D.D., Arçari, D.P., Pedrazzoli Jr., J., Martinez, C.A., Analysis of oxidative DNA damage in patients with colorectal cancer (2008) Clin Colorectal Cancer, 7 (4), pp. 267-272Lodish, H., Berk, A., Zipursky, S.L., Matsudaira, P., Baltimore, D., Darnell, J., A integração das células nos tecidos (2004) Biologia Celular E Molecular, pp. 968-1002. , In: Lodish H, Berk A, Zipursky SL, Matsudaira P, Baltimore D, Darnell J. (eds.), Rio de Janeiro: RevinterDuband, J.L., Thiery, J.P., Spatio-temporal distribution of the adherens junction-associated molecules vinculin and talin in early avian embryo (1990) Cell Differ Dev, 30 (1), pp. 55-76Rao, R.K., Basuroy, S., Rao, V.U., Karnaky, K.J., Gupta, A., Tyrosine phosphorylation and dissociation of occludin-ZO-1 and E-cadherin-b-catenin complexes from the cytoskeleton by oxidative stress (2002) Biochem J, 368 (PART. 2), pp. 471-481Schmehl, K., Florian, S., Jacobasch, G., Salomon, A., Körber, J., Deficiency of epithelial basement membrane laminin in ulcerative colitis affected human colonic mucosa (2000) Int J Colorectal Dis, 15 (1), pp. 39-48Cooper, H.S., Murthy, S., Kido, K., Yoshitake, H., Flanigan, A., Dysplasia and cancer in the dextran sulfate sodium mouse colitis model. Relevance to colitis-associated neoplasia in the human: A study of histopathology, B-catenin and p53 expression and the role of inflammation (2000) Carcinogenesis, 21 (4), pp. 757-768Fodde, R., Tomlinson, I., Nuclear beta-catenin expression and Wnt signalling: In defence of the dogma (2010) J Pathol, 221 (3), pp. 239-241Baskol, M., Baskol, G., Koçer, D., Ozbakir, O., Yucesoy, M., Advanced oxidation protein products: A novel marker of oxidative stress in ulcerative colitis (2008) J Clin Gastroenterol, 42 (6), pp. 687-691Glei, M., Hovhannisyan, G., Pool-Zobel, B.L., Use of Comet-fish in the study of DNA damage and repair: Review (2009) Mutat Res, 681 (1), pp. 33-43