CLDN1 and abscess: Bu and BAs treatment markedly reduced cumulative scores characterized by inflammatory infiltration, goblet cell loss, crypt density, submucosal inflammation, and crypt abscesses, and substantially increased mucus layer thickness and goblet cell numbers (Fig. 5f–i), as well as mRNA and protein levels of ZO-1, Claudin-1, and Occludin in the colon, when compared to the results of the Con group (Supplementary Fig. 7).