Effect of Shaoyao Tang on ulcerative colitis in rats via regulation of TLR4/NF-κB signal pathway / 中国中药杂志

ABSTRACT

The aim of this paper was to investigate the effect of Shaoyao Tang on ulcerative colitis(UC) in rats via regulation of TLR4/NF-κB signal pathway. A total of 56 Wistar rats were randomly divided into 6 groups normal control group(double distilled water), model group(double distilled water), mesalazine group(10 mL·kg~(-1)), high dose, middle dose and low dose Shaoyao Tang groups(2.4, 1.2, and 0.6 g·mL~(-1)). After UC rat models were established by 2, 4-dinitrochlorobenzene(DNCB)/ethanol enema, the rats received double distilled water or corresponding drugs twice a day for 7 days. After the treatment cycle, the general performance and disease activity index(DAI) of rats were observed on the next day. Then the rats were sacrificed. The length of colon was measured. Macroscopic and histological score of colon were evaluated. Histopathological changes of colon were observed by HE staining. Ultraviolet spectrophotometry detection was used to detect the content of myeloperoxidase(MPO) in blood and colon tissues. The levels of P-selectin, macrophage migration inhibitory factor(MIF) and thromboxane B_2(TXB_2) in blood and colon tissues were determined by ELISA. Immunohistochemistry and Western blot analysis were performed to detect the protein expressions of TLR4 and NF-κB in colon tissues. The results showed that as compared with the model group, Shaoyao Tang of different doses improved the general performance of UC rats. Moreover, high-dose Shaoyao Tang group showed the most obvious effect in scoring of disease activity index(P<0.001); both medium and high doses of Shaoyao Tang significantly inhibited the colon shortening and pathological injury, with significantly decreased expression levels of MPO, P-selectin, MIF and TXB_(2 )in serum and colon tissues of UC rats(P<0.001). Immunohistochemistry and Western blot assay showed that the levels of TLR4 and NF-κB protein expression in the colon tissues of Shaoyao Tang high-dose group were remarkably lower than that in the model group(P<0.001). This study shows that Shaoyao Tang has protective and repairing effects on UC, and its possible mechanism is achieved probably by regulating the TLR4/NF-κB pathway and inhibiting the expressions of MPO, P-selectin, MIF and TXB_2.