Effect of fibrinogen depletion and PAR-4 deficiency on liver regeneration after PHx. Mice were euthanized 30 minutes or 3 days after sham or PHx. (A) Representative images of fibrin(ogen) immunohistochemical staining 30 minutes after PHx in vehicle-treated (control, upper panel) and ancrod-treated (lower panel) mice. (B) Quantification of fibrin(ogen) deposition after PHx, expressed as positive pixel count (n = 8). (C) Representative images of Ki-67–stained livers 3 days after PHx for vehicle-treated mice (upper panel), mice receiving ancrod 2 hours before PHx (middle panel), and mice receiving ancrod 2 hours after PHx (lower panel). (D) Quantification of Ki-67–positive hepatocytes, expressed as percentage of total number of hepatocytes for control mice (n = 8), and mice treated with ancrod 2 hours prior (n = 8) or after (n = 7) PHx. (E) Quantification of Ki-67–positive hepatocytes, expressed as percentage of total number of hepatocytes for WT and PAR-4^−/− mice (n = 6 for sham, n = 7 for PHx). (F) Representative images of Ki-67–stained livers for sham (upper panels) or PHx (lower panels) 3 days after surgery for WT and PAR-4^−/− mice. Horizontal lines represent the mean; closed circles are individual mice. *P < .05.