Since mutual activation between FXR and Nrf2 has been reported [71,72], our findings suggest active roles of FXR and Nrf2 linking Sirt1 and bile acid metabolism, as well as their functional interplay in mediating the hepatoprotective actions of 18β-Glycyrrhetinic acid against cholestatic liver injury. The gene discussed is NFE2L2; the disease is medical procedure.