Figure 3.

U. parvifolia inhibits integrin α_IIbβ₃-mediated inside-out and outside-in signaling. (A, B) Flow cytometric measurements of fibrinogen binding in platelets treated with vehicle, various U. parvifolia extract concentrations or EGTA [(a) Resting, (b) Vehicle, (c) 25 µg/ml, (d) 50 µg/ml, and (e) 100 µg/ml, (f) 10 µM EGTA)] and stimulated with collagen (b-f). (C) Results of fibronectin adhesion assay, which was performed using an assay kit according to the manufacturer's protocol and by following the procedure described in the methods section. (D) In vitro effect of U. parvifolia extract on clot retraction for 2 h at room temperature after thrombin addition and photographed with 15 min intervals. Representative images of clot retraction at 90 min after thrombin addition in the presence and absence of U. parvifolia extract. Y-27632 (ROCK inhibitor) was used as a control. (F) Kinetics of clot retraction were measured by Image-J software and clot surface areas were plotted as a percentage of retraction. Bar graphs summarizing the inhibitory effect of U. parvifolia extract on fibrinogen binding to integrin α_IIbβ₃ (B), fibronectin adhesion (C), clot retraction (E), and kinetics of clot retraction (F). Results are shown as mean ± SD values from at least four independent experiments. *p < 0.05, **p < 0.01, and ***p < 0.001 versus control.