Objective  To examine protective effect and mechanism of Yinchen Wuling Powder (composed of Chinese medicinal herbs including Artemisia capillaris, Poria cocos, Rhizoma alismatis, Polyporus umbellatus, Ramulus cinnamomi, and Rhizoma atractylodis) on liver function in young rats with cholestasis.

  Methods  Totally 72 young Sprague-Dawley (SD) rats were randomly divided into 6 groups (6 males and 6 females in each group): a blank control and a model group with normal saline, an ursodeoxycholic acid (UDCA, at the dose of 0.10 g/kg) group, and low, moderate, high dose (100, 200, 400 g/kg) Yinchen Wuling Powder groups. The administrations were conducted by gavage once a day continuously for 6 days before and 2 day after the establishment of cholestasis model induced by intragastric administration of 0.5% α-naphthalene isothiocyanate (ANIT) at the dosage of 50 mg/kg in all rats except for those of control group. Twelve hours after the last administration, all rats′ bile were collected and blood specimens were sampled for detections of serum alkaline phosphatase (ALP), γ-glutamyltransferase (γ-GT), total bile acid (TBA), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) with biochemical method; the rats′ liver tissue specimens were also sampled for detections of superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), and glutathione peroxidase (GSH-Px) in liver homogenate with biochemical method, the observation of pathological changes in liver tissues with hematoxylin-eosin (HE) staining; and determinations of protein expression of Kelch-like ECH-associated protein 1(Keap1), nuclear factor erythroid-2-related factor-2 (Nrf2), reduced coenzyme/quinone oxidoreductase (NQO1), and heme oxygenase 1 (HO-1) with Western blot.

  Results  Compared with those in the blank control rats, significantly higher serum ALP, γ-GT, TBA, ALT and AST and lower bile secretion, SOD, CAT and GSH-Px in liver tissues were detected in the model rats (P < 0.05 for all); disordered arrangement of hepatocyte cords, enlargement/spotty necrosis/vacuolar change of the hepatocytes, and a large number of inflammatory cell infiltration were observed in the model rats′ liver tissues; significantly higher expression of Keap1 but lower expressions of Nrf2, NQO1 and HO-1 in liver tissue were also detected (all P < 0.05). In comparison with the model rats, the rats of UDCA group and high/moderate dose Yinchen Wuling Powder groups had significantly lower serum ALP, γ-GT, TBA, ALT, AST and MDA in liver homogenate but higher bile secretion, SOD, CAT and GSH-Px in liver homogenate (all P < 0.05); the rats of the three groups also had significantly higher protein expressions of Nrf2, NQO1 and HO-1 but lower expression of Keap1 (P < 0.05 for all) and obviously alleviated pathological damage in liver tissues.

  Conclusion  Yinchen Wuling Powder is of protective effect on liver injury induced by ANIT in young rats with cholestasis, and the mechanism of the effect may be related to inhibited expression of Keap1, up-regulated expression of Nrf2, improved antioxidant capacity, and alleviated oxidative stress injury in liver.