Galanin receptor pan-antagonist M40 reduces biliary hyperplasia and hepatic fibrosis in Mdr2KO mice. Two-month–old male and female Mdr2KO and FVBN mice were treated with M40, a non-specific antagonist of GalR1 and GalR2, and tested for intrahepatic biliary duct mass hyperplasia and hepatic fibrosis markers. A: Representative images of cytokeratin (CK) 19 immunohistochemistry (IHC). B: Quantification of CK19 by image analysis. C: Images of desmin IHC in mice treated with vehicle (Veh) or M40. D: Quantification of desmin staining. E: IHC images of α-smooth muscle actin (α-SMA) in liver of mice treated with vehicle or M40. F: Quantification of α-SMA expression based on image analysis. G: Images of Sirius Red staining of collagen I and III in liver of mice treated with vehicle or M40. H: Quantification of Sirius Red–stained collagen I and III in liver of mice treated with vehicle or M40. n = 4 (B, D, F and H). *P < 0.05 M40 versus vehicle; †P < 0.05 Mdr2KO versus FVBN; ‡P < 0.05 male versus female. Scale bars = 100 μm (A, C, E, and G).