OBJECTIVETo establish the rat model of acute pulmonary embolism, and study the changes of vascular active substances in pulmonary embolism rats, and investigate the interventive effect of anticoagulant drugs on vascular active substances.

METHODSOne hundred and twenty-eight rats were randomly divided into four groups: control group, model group, low-molecular-weight heparin and warfarin treated group and rivaroxaban-treated group (n = 32 in each group). The method of autologous thrombosis was used to establish the animal model of acute pulmonary embolism. The animals were treated with saline or different anticoagulant drugs. The physiological and biochemical parameters were detected at different time points after embolization. The rats were killed after embolism of 24 h, 3 d, 5 d or 1 week respectively and the pathologic samples of lung tissues were collected to analyze the pulmonary pathological changes in different groups.

RESULTSRats in embolization group after blood clots injection showed shortness of breath, oral cyanosis; quicken heart rates and other symptoms. All embolization groups had pulmonary hypertension, the levels of type B natriuretic peptide (BNP) were increased significantly. The ratio of endothelin-1 (ET-1)/NO and thromboxane (TXB2) and prostacyclin (6-k-PGFla) were abnormal. After treated with effective anticoagulant drugs, the levels of BNP, ET-1, NO, TXB2 and 6-k-PGF1a were tended to the normal levels in the control group. The pulmonary hypertensions were gradually decreased. The efficacy of rivaroxaban on pulmonary embolism was the same as that of the low molecular weight heparin or warfarin.

CONCLUSIONAnticoagulation therapy can effectively improve endothelial function after pulmonary embolism, reduce pulmonary hypertension, and revise the increased BNP levels to normal levels. The efficacy of rivaroxaban is not inferior to that of low molecular weight heparin and warfarin.