Abstract:Objective: To study gene expressions of farnesoid X receptor(FXR) and multidrug resistance associated protein3(MDR3) in human normal hepatocytes HL-7702 cell through the effect of Yinzhihuang injection (YZH), in order to explore the target and mechanism of YZH injection in regulating hepatic bile acid metabolism, and provide an experimental basis for the clinical application of YZH in the treatment of intrahepatic cholestasis. Method: HL-7702 was treated with different concentrations of YZH. The effect of YZH on the activity of HL-7702 was explored by cell counting kit-8 (CCK-8). Real-time PCR was used to determine YZH's ideal intervention concentration and time. The gene expression of FXR was up-regulated by GW4064 (agonist of FXR), and divided into YZH group, GW4064 group, GW4064+YZH group, normal group and DMSO control group. The gene expression of FXR was silenced by small interfering RNA (siRNA) and divided into siRNA group, siRNA+YZH group, normal group and negative group. Relative mRNA and protein expressions of FXR and MDR3 were detected by real-time quantitative PCR and Western blot, and the protein expression of FXR was detected by immunofluorescence(IF). Result: The ideal intervention concentration of YZH on HL-7702 was 1.08%, the ideal intervention time was 15.47 h, and YZH had an effect on the activity of HL-7702 in a dose-dependent manner. Compared with the normal group, GW4064 group promoted the mRNA and protein expressions of FXR and MDR3(P<0.01). Compared with the normal group, siRNA group inhibited FXR and MDR3 mRNA and protein expressions (P<0.01). Compared with GW4064 group, GW4064 group + YZH group promoted the mRNA and protein expressions of FXR and MDR3 (P<0.01). Compared with siRNA group, siRNA + YZH group promoted the mRNA and protein expressions of FXR and MDR3(P<0.01). Conclusion: YZH promotes FXR and MDR3 mRNA and protein expressions. YZH regulates hepatic bile acid metabolism by promoting the expression of MDR3 mRNA and protein with FXR. This study provides an experimental basis for its clinical application in the treatment of intrahepatic cholestasis.