Hydrogen sulfide exerts antithrombotic effects and inhibits deep vein thrombosis through NOS-PECAM-1 signaling pathway

Deep vein thrombosis (DVT) is initiated in aggregation and adhesion of inflammatory cells to vascular endothelium mediated by adhesion molecules, thereby activating platelets and inducing thrombosis. Hydrogen sulfide (H2S) is a gasotransmitter with anti-adhesive, anti-inflammatory and vasoactive properties. This study aimed to investigate the inhibitory effect of platelet aggregation and thrombosis by H2S. Platelet aggregation by H2S was measured in human washed platelets. A mouse DVT model was established by femoral vein ligation, with intraperi-toneally injected sodium hydrosulfide (NaHS, 10 mmol/kg per day) or saline for 6 days before thrombosis. After 48 hours, thrombus weight was measured and the femoral vein tissue was harvested to detect the expression of endothelial NOS (eNOS), inducible NOS (iNOS) and PECAM-1 expressions. Small interfering RNA (siRNA) was applied to inhibit PECAM-1 expression in HUVECs cells to explore the role of PECAM-1 in the anti-thrombotic effect. Our results showed that NaHS inhibited aggregation of human washed platelets in a concentration dependent manner, which could be attenuated by L-NAME, a nitric oxide synthase inhibitor. NaHS significantly decreased thrombus weight and increased protein expressions of PECAM-1, eNOS and iNOS in DVT mice. Inhibition of PECAM-1 expression in HUVECs by small interfering RNA (siRNA) can significantly increase the adhesion activity of HUVECs and platelets and attenute inhibition of platelet function by hydrogen sulfide. In conclusions, H2S demonstrates inhibitory effects on platelet activation and thrombosis involving the NOS-PECAM-1 pathway and may have preventive and therapeutic value for DVT and other clinical disorders with increased risk of thrombotic events.