Objective: To evaluate the efficacy of Sijunzi decoction in treatment of 2

4

6-trinitrobenzene sulfonic acid (TNBS)-induced ulcerative colitis and investigate its effect on expression of tight junction protein Occludin in mucosal epithelial cells. Method: SD rats were divided into normal group

model group (TNBS-induced colitis)

Sijunzi Tang(SJZT) high dose group

middle dose group and low dose group (crude drug 5.6

2.8

1.4 g·kg-1)

and Salazosulfapyridine treatment group (SASP

0.4 g·kg-1)

n=8 in each group(P < 0.05). Experimental ulcerative colitis models were induced by rectal instillation of TNBS in all groups except normal group. 24 h after modeling

drugs were given intragastrically continuously for ten days according to their respective doses in each group. Their diet conditions

mental state

disease activity index (DAI) scores

stool frequency and body weight were observed. 24 h after the last administration

the rats were sacrificed and their colon was taken. The pathological changes of colonic mucosa were visually observed and their scores of colon macroscopic damage index (CMDI) were recorded. Lesion areas were taken for HE staining

and colon tissues damage index (TDI) was evaluated under light microscopy

expression of Occludin proteins in colon of the rats was detected by immunohistochemical method. Result: DAI scores

CMDI scores and TDI scores in model group were higher than those in control group

Occludin protein expression was lower than in control group. However

SJZT and SASP treatment could reduce damage to mucosa of TNBS-induced UC models

increase the expression of tight junction proteins Occludin

inhibit the increase of colonic permeability

and protect the colonic mucosal barrier function(P < 0.05). Conclusion: SJZT can increase Occludin protein expression and promote the recovery of colonic mucosal barrier function in UC rats

which may be one of its mechanism for treatment of colitis.