AIM:To establish and evaluate a colonoids model of intestinal barrier dysfunction with irritable bowel syndrome(IBS).METHODS:The colonic recess of 20～22 g male C57BL/6 mice were isolated and cultured in ma-trix glue to proliferate and differentiate into 3D hollow spheres with colonic epithelioid structure.The following experi-ments were carried out:(1)Colonoids and colonic tissues of mice were detected by immunofluorescence to identify colo-noids.(2)Fluorescein isothiocyanate dextran 4(FD4)evaluated the epithelial barrier function of colonoids.(3)To ex-plore the changes in the epithelial barrier of colonoids induced by interferon-γ(IFN-γ)at different concentrations and time points.FD4 and HE staining were used to evaluate the barrier function.RT-qPCR was used to detect the mRNA expres-sion of occludin and zonula occludens-1(ZO-1)in tight junctions of colonoids.Immunofluorescence was used to detect the distribution and localization of occludin and ZO-1 proteins.RESULTS:(1)The expression of EdU proliferation and in-testinal epithelial cell lineage markers in colonoids was consistent with that in mouse colonic tissues.(2)In the control group,FD4 did not infiltrate the colonoids lumen,but FD4 significantly infiltrated the colonoids lumen induced by ethyl-ene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid(EGTA).(3)From 18 h,the IFN-γ at 60,100,200 and 240 ng/mL could significantly infiltrate into the cavity of colonoids(0.033,0.032,0.042 and 0.001),and the barri-er injury of colonoids could be seen by HE staining.After 18 h,all concentrations of IFN-γ could significantly decrease the mRNA expression of occludin and ZO-1,and the fluorescence of occludin and ZO-1 decreased significantly(P<0.05).CONCLUSION:(1)The cultured organoids are colonoids with complete epithelial barrier.(2)IFN-γ could in-duce the decrease of the transcriptional levels of occludin and ZO-1 in the tight junction of colonoids,the decrease of the expression of corresponding proteins,and the change of localization and distribution,thus increasing the epithelial perme-ability of colonoids.This model is highly consistent with the pathophysiological state of IBS colonic mucosal barrier dys-function,which provides a new tool and method for studying the direction of colonic mucosal barrier dysfunction in IBS.