Thrombus formed by discoid platelets visualized by in vivo imaging after laser/ROS-induced injury. (A) In vivo imaging enabling selective visualization of multiple cell types. Platelets, erythrocytes, and leukocyte/EC nuclei were visualized with an anti-GPIbβ antibody (green), fluorescent dextran (red), and Hoechst 33 342 (blue), respectively, in mesenteric capillaries of 12-week-old male control mice. Correspondingly colored arrows point to each cell type, and the white arrow indicates the direction of blood flow. (B) Discoid platelets contribute to thrombus formation after laser/ROS-induced injury. The microcirculation of the mesentery in living animals was visualized after laser/ROS-induced initiation of thrombus formation. (C) ROS production triggers thrombus formation. ROS production in the affected blood vessel after laser/ROS-induced injury was visualized by the administration of APF (red) with dextran (green). The red arrow indicates the developing thrombus. Original movies for panels A and B are available as supplemental Videos 1 and 2. (D-E) Distrbution of fibrinogen in a developing thrombus after short-term (D, 0-20 seconds) and long-term (E, 10 minutes) laser-induced injury. Injected fluorescent fibrinogen is shown in red, and dextran is in green. All scale bars are 10 μm.