Inhibition of APC enhances thrombus formation after FeCl₃ injury of the mouse jugular vein. (A) Graphs show platelet accumulation in vehicle- (red) and Ab1609-treated (blue) mice after FeCl₃ induced injury of the mouse jugular vein: platelet accumulation over the entire time course of the experiment (i), and platelet accumulation 180 seconds post-FeCl₃ removal (ii). (B) Corresponding graphs showing fibrin accumulation after FeCl₃ induced injury. All values are mean ± standard error of the mean. Statistics were performed using the Mann-Whitney test; n = 7 vehicle- and 7 Ab1609-treated mice. (C-F) Scanning electron microscopy images of the intravascular side of the jugular vein after FeCl₃ injury. (C-D) Representative thrombus formed in a vehicle-treated mouse 3 minutes after removal of FeCl₃. Scale bars, 500 and 30 μm, respectively. (E-F) Corresponding images of a representative thrombus from an Ab1609-treated mouse. Insets in panels D and F show a higher-magnification view of the vessel surface; note the exposed endothelium and lack of fibrin formation in the vehicle-treated mouse (panel D inset) vs a fibrin-, red blood cell–, and platelet-rich thrombus in the presence of Ab1609. White arrows indicate the direction of blood flow (C,E). Images are representative of n = 4 mice in each group (images from additional mice are included in supplemental Figure 9).