Fig. 4

Annexin V binding reveals rapid exposure of phosphatidylserine (PSer) on endothelial cell surfaces but not on platelets. a Confluent endothelial cells before injury show no PSer exposure on their surfaces (top left). Immediately after mechanical injury is induced, the endothelial cells in the strict vicinity of the wound exhibit PSer exposure, as measured with annexin V binding (red) in a time-dependent manner while losing their plasma membrane staining over the time course (blue). In contrast, platelets (green) adhered at the injury site did not exhibit PSer exposure. b Thirty minutes after the injury was induced and hemostasis was achieved, the majority of the platelet aggregates did not exhibit significant amounts of PSer exposure, in contrast with endothelial cells at the wound site, which exhibit significant PSer exposure. All scale bars = 50 µm