Adhesion to collagen but not laminin is inhibited by prior treatment with collagenase. (A) Coverslips were coated with 50 μg/mL collagen (i) or 50 μg/mL laminin (ii) as described in Figure 1. After rinsing with PBS, coverslips were incubated with 0.1 mg/mL collagenase in TES buffer containing 0.36 mM CaCl2 for 2 hours at 35°C. After washing with PBS, coverslips were blocked with 2% fatty acid–free BSA for 2 hours. Washed murine platelets (3 × 107/mL) were incubated with 2 mM GRGDS peptide and seeded on coverslips for 30 minutes at room temperature. Adherent platelets were fixed, permeabilized, stained, and photographed using fluorescent microscopy as described in Figure 1. (B) The number of adherent platelets was counted as described in Figure 3.
