Objective:To investigate effect of Buyang Huanwu Decoction(BHD) and its active fractions such as alkaloid and glycoside on activities of antithrombin Ⅲ(AT-Ⅲ) and protein C(PC) after carotid arterial thrombosis induced by ferric chloride in rats. Methods: Rats were administered with tested drugs and then left carotid artery was applied with FeCl3 to form thrombus.The activities of antithrombin Ⅲ(AT-Ⅲ) and protein C(PC) in plasma in rats were determined by chromogenic substrate assay.Results:BHD

alkaloid and glycoside could decrease thrombotic weight (P<0.05).The activities of AT-Ⅲ in the model group were significantly lower than those of the sham-operated group(P<0.01).The activities of ATⅢ in BHD and alkaloid group were markedly lower than those of the model group(P<0.01)

No significant difference was found in activities of AT-Ⅲ between the glycoside and model group(P>0.05).The activities of PC in the model group were slightly lower than those of the sham-operated group(0.10>PP>0.05).Compared with the model group

the activities of PC in alkaloid group were decreased(P<0.05).But the activities of PC in BHD and glycoside group were increased when compared to the model group(P<0.01) and sham group(P<0.01).Conclusions: BHD

alkaloid and glycoside could inhibit thrombosis. Antithrombotic actions of BHD may be related to binding with AT-Ⅲ

and it could also prevent the consumption of PC after carotid arterial thrombosis.Antithrombotic action of alkaloid may concerne inactivating coagulation factors by binding with AT-Ⅲ or accelerating inactivation of coagulation factors by PC.Antithrombotic action of glycoside may not be related to AT-Ⅲ and PC.