ABSTRACT
AIM:To investigate the protective effect of Zhenrenyangzang decoction (ZRYZ) on the intestinal mucosal barrier function and the expression of tight junction proteins,zonula occludens-1 (ZO-1) and occludin,in the co-lon of rats with trinitrobenzenesulfonic acid (TNBS)-induced ulcerative colitis in order to explore the possible mechanism involved. METHODS:Male Wistar rats were randomly divided into normal group, model group, salazosulfapyridine (SASP) positive control group,high-dose ZRYZ(ZRYZ-H) group and low-dose ZRYZ(ZRYZ-L) group. Except the nor-mal group,the rats in other groups were given the TNBS/50% ethanol mixed solution by enema to make the ulcerative coli-tis model. The rats in positive control group were given SASP suspension liquid. The rats in ZRYZ-H group and ZRYZ-L group were orally administered with ZRYZ at doses of 30.4 g/kg and 15.2 g/kg, respectively, while the rats in normal group and model group were orally administered with saline. All the drugs were administered to the rats for consecutive 21 d. Disease activity index (DAI) was investigated during the drug treatment, and colon samples were collected after drug administration for evaluating morphological damage score. Intestinal mucosal permeability was measured by detection of lac-tulose/mannitol (L/M) in urine. Colonic myeloperoxidase(MPO) activity and goblet cell number,serum diamine oxidase (DAO) and D-lactic acid (D-LA) levels, and the colonic expression of ZO-1 and occludin were also measured. RE-SULTS:Compared with normal group,DAI,morphological damage score,L/M value,colonic MPO activity as well as se-rum D-LA and DAO levels in model group significantly increased(P<0.05),while goblet cell number as well as the ex-pression levels of ZO-1 and occludin in model group were significantly reduced(P<0.05). Compared with model group, DAI,morphological damage score,L/M value,colonic MPO activity as well as serum DAO and D-LA levels in ZRYZ-H group and ZRYZ-L group were reduced significantly(P<0.05),while goblet cell number as well as the expression of ZO-1 and occludin in ZRYZ-H group and ZRYZ-L group increased significantly(P<0.05). CONCLUSION:ZRYZ protects the intestinal mucosal barrier function in ulcerative colitis rats by reducing intestinal mucosal permeability,and its mecha-nisms may be related to increasing the expression of ZO-1 and occludin.