Study on protective effect of Chaihu Shugan Powder against liver injury in rats with intrahepatic cholestasis by regulating FXR/Nrf2/ARE pathway

Abstract

This study aims to investigate the effect of Chaihu Shugan Powder(CHSG) on liver injury in rats with intrahepatic cholestasis by regulating farnesoid X receptor(FXR)/nuclear factor erythroid-2-related factor(Nrf2)/antioxidant response element(ARE) pathway. Eighty-four SD rats were classified into normal group, model group, CHSG-L group(0.5 g·kg~(-1)), CHSG-H group(2.5 g·kg~(-1)), ursodeoxycholic acid group(UDCA group, 100 mg·kg~(-1)), CHSG-H+sh-NC group(2.5 g·kg~(-1) CHSG+subcutaneous injection of sh-NC lentivirus), CHSG-H+sh-FXR group(2.5 g·kg~(-1) CHSG+subcutaneous injection of sh-FXR lentivirus), with 12 rats in each group. Rats were treated with corresponding drugs except for the normal group and the model group, once a day, for 7 days. On 5 th day, rats, except the normal group, were given α-naphthalene isothiocyanate(ANIT) at a dose of 100 mg·kg~(-1), once a day for 3 days to induce intrahepatic cholestasis, and the normal group was given the same amount of normal saline. Rats were anesthetized 1 h after the last administration and the 2 h bile flow was measured. Aeroset chemistry analyzer was employed to detect the levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), total bilirubin(TBIL), and total bile acid(TBA) in rat serum. Based on hematoxylin and eosin(HE) staining, the pathological changes of rat liver tissue were observed. Glutathione peroxidase(GSH-Px), superoxide dismutase(SOD), and malondialdehyde(MDA) in rat liver tissue homogenate were monitored with corresponding kits. Western blot was used to detect the expression of FXR, Nrf2, and heme oxygenase-1(HO-1) proteins in rat liver tissue. Compared with the normal group, the model group showed many spots or concentrated necrotic areas in the liver tissue, infiltration of a large number of inflammatory cells, swelling liver cells with nuclear shrinkage. The 2 h bile flow, levels of GSH-Px and SOD, and relative expression of FXR, Nrf2, and HO-1 proteins were significantly lower, and the levels of ALT, AST, TBIL, TBA and MDA were significantly higher in the model group than in the normal group. Compared with the model group, CHSG-L group, CHSG-H group, and UDCA group demonstrated significant alleviation of pathological damage of the liver tissue, significantly high 2 h bile flow, levels of GSH-Px and SOD, and expression of FXR, Nrf2 and HO-1 proteins, and significantly low levels of ALT, AST, TBIL, TBA and MDA. Compared with the CHSG-H group, the CHSG-H+sh-FXR group had worse liver pathological damage, significantly low levels of 2 h bile flow, levels of GSH-Px and SOD, and expression of FXR, Nrf2, and HO-1 proteins, and significantly high levels of ALT, AST, TBIL, TBA, and MDA. CHSG may protect against liver injury in rats with intrahepatic cholestasis by activating the FXR/Nrf2/ARE pathway.