Therapeutic efficacy and mechanism of Zhenrenyangzang decoction in rats with experimental ulcerative colitis.

Zhenrenyangzang Decoction (ZD) has been used as a classic formula in China for the treatment of gastrointestinal dysfunction such as chronic gastritis. However, there is less study on its application in ulcerative colitis (UC) and the effects are not yet clearly defined. To explore the effectiveness of ZD in trinitrobenzene sulfonic acid (TNBS)-induced UC rats, ZD was administered orally for 8 days at a dosage of 2, 4 or 8 g/kg/day. Following drug administration, the disease activity index (DAI) and tissue damage scores were recorded. In addition, mRNA and protein expression of nuclear factor kappa B (NF-κB), p38 mitogen activated protein kinase (p38MAPK) and Toll-like receptor 2 (TLR2) in colon tissues were examined by real time PCR and western blotting assay. As compared with the UC model group, ZD promoted the recovery of colitis and inhibited the colonic inflammation damage in UC rats by reducing the mRNA or protein expression of NF-κB and p38MAPK, as well as activating the production of TLR2 in colon tissues. And ZD significantly reduced the DAI and tissue damage scores. The therapeutic effect of ZD was found to be comparable to that of SASP. Our results suggested that ZD could improve colonic mucosa impairment and possesses favorable therapeutic action in TNBS-induced colitis, which provides direct pharmacological evidence for its clinical application.