The exact mechanism of the TNBS-induced ulcerative colitis animal model remains unclear. It is believed that when TNBS dissolved in ethanol is administered intracolonically, ethanol acts as an organic solvent that dissolves the mucus layer on the intestinal mucosa and disrupts the mucosal barrier, thereby increasing mucosal permeability to TNBS in the intestinal lumen. Since the intestinal immune system cannot completely eliminate the large amount of TNBS entering the mucosa, TNBS covalently binds to lysine residues on colonic epithelial cells, altering surface proteins and forming autoantigens. This triggers a series of immune responses directed against the intestinal mucosa. Therefore, the combined use of TNBS and ethanol is critical for the successful establishment of this model.

Modeling method: The ulcerative colitis model was established by intracolonic infusion of TNBS/ethanol solution.
Positive drug: Azathioprine tablets
Evaluation indicators: CMDI score, HE staining

CMDI

HE staining of colon tissue