Ginsenoside Rk1 suppresses platelet mediated thrombus formation by downregulation of granule release and αIIbβ3 activation

Fig. 1. Effects of G-Rk1 on platelet aggregation and cytotoxicity. (A) Effect of G-Rk1 on collagen-induced human platelet aggregation. (B) Effect of G-Rk1 on thrombin-induced human platelet aggregation. (A) Effect of G-Rk1 on U46619-induced human platelet aggregation. (D) Effect of G-Rk1 on cytotoxicity. Platelet aggregation and cytotoxicity were carried out as described in “Materials and Methods” section. The data are expressed as the mean ± standard deviation (n = 4). ∗p < 0.05, ∗∗p < 0.01 versus each agonist-stimulated human platelets. NS, not significant.

Fig. 2. Effects of G-Rk1 on [Ca2+]i mobilization and IP3RI phosphorylation. (A) Effect of G-Rk1 on collagen-induced [Ca2+]i mobilization. (B) Effect of G-Rk1 on collagen-induced IP3RI (Ser1756) phosphorylation. (C) Effects of G-Rk1 on collagen-induced ATP release. [Ca2+]i mobilization, ATP release and Western blot were performed as described in “Materials and Methods” section. The data are expressed as the mean ± standard deviation (n = 4). ∗p < 0.05, ∗∗p < 0.01 versus the collagen-stimulated human platelets.

Fig. 3. Effects of G-Rk1 on TXA2 generation and cPLA2 and p38 MAPK phosphorylation. (A) Effects of G-Rk1 on collagen-induced TXA2 generation. (B) Effect of G-Rk1 on collagen-induced cPLA2 (Ser505) phosphorylation. (C) Effect of G-Rk1 on collagen-induced p38 MAPK phosphorylation. Measurement of TXA2 generation and Western blot was performed as described in “Materials and Methods” section. The data are expressed as the mean ± standard deviation (n = 4). ∗p < 0.05, ∗∗p < 0.01 versus the collagen-stimulated human platelets.

Fig. 4. Effects of G-Rk1 on fibrinogen binding to αIIb/β3 and Fibronectin adhesion. (A) The flow cytometry histograms on fibrinogen binding. a, Intact platelets (base); b, Collagen (2.5 μg/mL); c, Collagen (2.5 μg/mL) + G-Rk1 (3.75 μM); d, Collagen (2.5 μg/mL) + G-Rk1 (7.5 μM); e, Collagen (2.5 μg/mL) + G-Rk1 (15 μM); f, Collagen (2.5 μg/mL) + G-Rk1 (30 μM). (B) Effects of G-Rk1 on collagen-induced fibrinogen binding (%). (C) Effects of G-Rk1 on collagen-induced fibronectin adhesion. Measurement of fibrinogen binding and fibronectin adhesion was carried out as described in “Materials and Methods” section. The data are expressed as the mean ± standard deviation (n = 4). ∗p < 0.05, ∗∗p < 0.01 versus the collagen-stimulated human platelets.

Fig. 5. Effects of G-Rk1 on VASP and Akt phosphorylation. (A) Effect of G-Rk1 on collagen-induced VASP (Ser157) phosphorylation. (B) Effect of G-Rk1 on collagen-induced Akt (Ser473) phosphorylation. Western blot was performed as described in “Materials and Methods” section. The data are expressed as the mean ± standard deviation (n = 4). ∗p < 0.05, ∗∗p < 0.01 versus the collagen-stimulated human platelets.

Fig. 6. Effects of G-Rk1 on fibrin clot retraction. (A) Photographs of fibrin clot (B) Effects of G-Rk1 on thrombin-retracted fibrin clot (%). Quantification of fibrin clot retraction was performed as describe in “Materials and Methods” section. The data are expressed as the mean ± standard deviation (n = 4). ∗p < 0.05, ∗∗p < 0.01 versus the thrombin-stimulated human PRP.

Fig. 7. G-Rk1 inhibits pulmonary thromboembolism in mice. Mice were pre-treated with saline, G-Rk1 (30 mg/kg i.p.), or ASA (100 mg/kg i.p.) once a day for 3 days (n = 10 in each group). One hour after the final administration, mice were challenged with a collagen + epinephrine mixture and checked for survival at 10 min. ∗∗∗p < 0.001 compared to the control group.