Inhibitory effects of hydrogen on in vitro platelet activation and in vivo prevention of thrombosis formation.

AIMS

Hydrogen (H) has antioxidant effects. The pharmacologic function of H in platelets is not yet clear. Therefore, in this study we sought to investigate the inhibitory effects of H on in vitro platelet activation and in vivo prevention of thrombus formation.

MAIN METHODS

After platelets were incubated with H-rich saline (HRS), platelet adhesion in whole human blood was assessed in fibrinogen-coated perfusion chambers, while rat platelet aggregation induced by ADP, collagen and HO was detected through light transmission aggregometry. The level of P-selectin, thromboxane B, nitric oxide (NO), malondialdehyde, reactive oxygen species (ROS), cGMP, extracellular signal-regulated kinases 1 and 2 (p-ERK1/2), and fibrinogen binding to platelets were evaluated in vitro. Besides, the in vivo effects were examined in arterio-venous shunt thrombosis, FeCl-induced artery thrombus formation, and tail bleeding time in mice and rats.

KEY FINDINGS

HRS prolonged tail bleeding time in mice and rats, decreased thrombus weight and prolonged the time to occlusion in rat and mouse thrombosis models in vivo and inhibited platelet adhesion as well as aggregation in vitro. Additionally, HRS decreased P-selectin expression, release of thromboxane B, ROS, and fibrinogen binding, but enhanced NO levels in HO-exposed platelets. HRS also decreased malondialdehyde levels in plasma of the rat arterial thrombosis or HO-exposed platelet model. Moreover, HRS increased cGMP level, decreased p-ERK1/2 (diminished with KT5823) in the platelets stimulated by HO.

SIGNIFICANCE

These results suggest that H has antithrombotic effects, which may be due to its antioxidant property and subsequent inhibition of platelet activation via NO/cGMP/PKG/ERK pathway.