ABT-263 treatment inhibits platelet thrombus formation in vivo. Platelet aggregate formation following ABT-263 (25 mg/kg orally) treatment in vivo was examined in mouse mesenteric venules after needle puncture injury, performed between 1.5 and 3 hours after ABT-263 treatment, and data grouped accordingly in half-hour intervals after treatment. Subsequent platelet accrual over a 15-minute period was monitored by intravital microscopy. (A) Representative images of average aggregate surface area from vehicle- or ABT-263–treated mice during the indicated time period. For clarity, platelet aggregates are demarcated. (B) The cumulative size of forming aggregates (μm2) measured over 50-second intervals for a maximum of 900 frames (15 minutes; 1 frame = 1 second). (C) Quantification of the average aggregate surface area (μm2) measured over 50-second intervals for a maximum of 900 frames (15 minutes). (B-C) Data represent the mean ± SEM where: Ctl 1.5 to 2.0 hours, n = 10; ABT-263 1.5 to 2.0 hours, n = 10; Ctl 2.0 to 2.5 hours, n = 20; ABT-263 2.0 to 2.5 hours, n = 23; Ctl 2.5 to 3.0 hours, n = 15; and ABT-263 2.5 to 3.0 hours, n = 22. *P < .05, ***P < .001.
