PLCγ2-deficient platelets showed limited integrin-dependent platelet adhesion on collagen at a medium rate of shear. Mouse blood anticoagulated with PPACK and heparin was perfused through a collagen-coated microcapillary at a shear rate of 800 s–1 for 2 minutes and nonadherent cells were washed for 8 minutes at the same shear rate with modified Tyrode buffer containing 2 mM CaCl2 and 1 U/mL heparin. After washing, microscope images were recorded from at least 6 different microscope fields. (A) Representative images of platelet adhesion from wild-type, PLCγ2–/–, and FcRγ-chain–/– mice. (B) Image analysis was performed off-line using ImagePro plus software. Platelet adhesion results are expressed as mean ± SEM surface area covered by platelets. (C) Blood from PLCγ2–/– mice was incubated without (control) or with 10 μM lotrafiban (lotra), 20 μg/mL anti-α2 antibody (HMα2; anti-α2) for 5 minutes before perfusion. Platelet adhesion is expressed as a percentage of control. *P < .05; **P < .01. The data were representative of 2 experiments.
