Antithrombotic effect of a novel tissue plasminogen activator from the venom of Gloydius brevicaudus viper

OBJECTIVE To investigate the thrombolytic and antiplatelet effects of a novel plasminogen activator from the venom of Gloydius brevicaudus viper(GBV-PA)in vitro and in vivo.METHODS Thrombolytic experiments were performed in rabbit models of ear vein thrombosis and carotid artery thrombosis,and in dog model of acute cerebral infarction.Inhibition of thrombus formation was evaluated in rat inferior vena cava thrombosis model and ferric chloride-induced arterial thrombosis.In vitro,we assayed the antithrombotic effect of GBV-PA on rabbit blood clots,euglobulin lysis time(ELT)of rabbit plasma,and on ADP-induced platelet aggregation.RESULTS GBV-PA intravenous administ ration significantly reduced vascular recanalization times of rabbit ear veins thrombosis and thrombus weight of rabbit carotid artery thrombosis.The arterial recanalization rates were dose-and time-dependently improved after administration of GBV-PA in canine acute cerebral infarction model.Thrombus length and weight was significantly reduced by GBV-PA both in rat inferior vena cava and ferric chloride-induced arterial thrombosis models.Thrombus formation of blood of rabbits they were administrated with GBV-PA was also inhibited.GBV-PA radically reduced plasma ELT of rabbit′s blood clots.ADP-induced platelet aggregation was inhibited by GBV-PA in a dose-dependent manner with a half-maximal inhibitory concentration of 19.9μg·mL-1.CONCLUSION This study demonstrates that GBV-PA is a thrombolytic and antiplatelet agent.It has significant antithrombotic effects on various in vitro and in vivo experimental models of thrombosis.The mechanisms that underline its antithrombotic effects were related to GBV-PA′s capabilities of increasing fibrinolytic activities and inhibition of platelet aggregation.