Ginsenoside Rg1 attenuates platelet activation under shear stress via multi-target suppression of PI3K/AKT and ERK1/2...

Ginsenoside Rg1, a key bioactive component of Panax ginseng, is recognized for its cardiovascular protective effects, yet its role in modulating platelet activation under high shear stress remains incompletely understood. This study aimed to systematically evaluate the in vitro effects and underlying mechanisms of Rg1 on platelet aggregation under high shear stress using a microfluidic chip system. In this study, blood flow environments at venous (300 s^-1), arterial (1500 s^-1), and pathological arterial (5000 s^-1) shear rates were simulated using microfluidic chips. The effects of Rg1 (0-1000 μM) on platelet aggregation and activation were assessed via fluorescence imaging, flow cytometry (measuring P-selectin and GP IIb/IIIa activation), and Western blot analysis of intracellular signaling pathways. Coagulation parameters (APTT, PT, TT) and blood compatibility were also evaluated. Our results showed that Rg1 concentration-dependently inhibited platelet aggregation across all tested shear rates, showing particularly pronounced suppression under high shear stress (5000 s^-1). Mechanistically, Rg1 significantly reduced P-selectin expression and GP IIb/IIIa activation. Western blot analysis revealed that Rg1 exerted its antiplatelet effects primarily by suppressing the PI3K/AKT and ERK1/2 signaling pathways and enhancing VASP phosphorylation, while exhibiting limited direct inhibitory effects on the Syk/PLCγ2 pathway. Notably, Rg1 did not significantly alter standard coagulation parameters or cause hemolysis within the tested concentration range. In conclusion, ginsenoside Rg1 demonstrated potent concentration-dependent inhibition of platelet activation and aggregation under high shear stress in this in vitro study. Its mechanism involves the multi-target modulation of key intracellular signaling pathways (PI3K/AKT, ERK1/2, and PKG/VASP). Furthermore, Rg1 exhibited favorable blood compatibility without impairing coagulation function in vitro. These findings suggest that Rg1 is a promising candidate warranting further preclinical investigation for targeted intervention in arterial thrombosis, although its therapeutic efficacy and safety require validation in vivo.