AIM:To evaluate the impacts of Schistosoma japoni-cum(S.japonicum) ova on the tight junction barriers in a trinitrobenzenesulfonic acid(TNBS)-induced colitis model.METHODS:Balb/c mice were randomly divided into three groups:control group;TNBS + ovagroup and TNBS + ova + group.TNBS was used intracolonic to in-duce colitis and mice of the TNBS + ova + group were pre-exposed to S.japonicum ova as a prophylactic intervention.Colon inflammation was quantified using following variables:mouse mortality,weight loss,co-lon extent and microscopic inflammation score.Serum expression of tumor necrosis factor-αand interferon-γ were assessed to evaluate the systemic inflamma-tory response.NOD2 and its mRNA were also tested.Bacterial translocations were tested by culturing blood and several tissues.ZO-1 and occludin were chosen as the representations of tight junction proteins.Both the proteins and mRNA were assessed.RESULTS:Ova pre-treatment contributed to the reliefof colitis and decreased the mortality of the models.NOD2 expression was significantly downregulated when pretreated with the ova.The TNBS injection caused a significant downregulation of ZO-1 and oc-cludin mRNA together with their proteins in the colon;ova pre-exposure reversed these alterations.Treat-ment with S.japonicum ova in the colitis model caused lower intestinal bacterial translocation frequency.CONCLUSION:S.japonicum ova can maintain epithelial barrier function through increasing tight junction pro-teins,thus causing less exposure of NOD2 to the lumi-nal antigens which may activate a series of inflamma-tory factors and induce colitis. AIM: To evaluate the impacts of Schistosoma japoni-cum (S. japonicum) ova on the tight junction barriers in a trinitrobenzenesulfonic acid (TNBS) -induced colitis model. METHODS: Balb / c mice were randomly divided into three groups: control group; TNBS + ovagroup and TNBS + ova + group. TNBS was used intracolonic to in-duce colitis and mice of the TNBS + ova + group were pre-exposed to S. japonicum ova as a prophylactic intervention. Colon inflammation was quantified using the following variables: mouse mortality, weight loss, co-lon extent and microscopic inflammation score. Serum expression of tumor necrosis factor-α and interferon-γ were assessed to evaluate the systemic inflamma-tory response. NO2 and its mRNA were also tested.Bacterial translocations were tested by culturing blood and several tissues. ZO-1 and occludin were chosen as the representations of tight junction proteins. Both the proteins and mRNA were assessed .RESULTS: Ova pre-treatment contributed to the reliefof colitis and decreased the mo rtality of the models. NOD2 expression was significantly downregulated when pretreated with the ova. TNBS injection caused a significant downregulation of ZO-1 and oc-cludin mRNA together with their proteins in the colon; ova pre -ized reversed these alterations.Treat- ment with S. japonicum ova in the colitis model caused lower intestinal bacterial translocation frequency. CONCLUSION: S. japonicum ova can maintain epithelial barrier function through increasing tight junction pro-teins, thereby causing less exposure of NOD2 to the lumi-nal antigens which may activate a series of inflamma-tory factors and induce colitis