Changes Of T-PA, PAI-1, VWF In Plasma In Acute Pulmonary Embolism Of Rabbit

Objective: Pulmonary embolism(PE) is an clinic syndrome caused by endogenous or exogenous embolus obstruct pulmonary artery. At present pathophysiology of PE has been investigated extensively and deeply. Change of pathophysiology of PE is complicated and changeable, principal bring impacts on respiratory system, haemodynamics, blood vessel endothelium function, which induce a series of cardiorespiratory disfunction and blood vessel endothelium disfunction. Documents were reported that tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1(PAI-1) had important effect on pathogenesis of coronary artery disease, acute cerebral accident disease by regulating fibrinolysis system function. Studies on t-PA and PAI-1 in PE were a few at present, but the results were different. vWF(von Willebrand disease)was a material released from endothelial cell as injured. It was linked with platelet activation and blood clotting ,usually looked as a marker of endothelial cell injury. We established acute APE models of rabbits to detect the levels of vWF, t-PA, PAI-1 in plasma on different time to explore endothelial cell injury and the change of fibrinolysis system function. Method: Thirty healthy New Zealand rabbits of either gender and weighing 2.5~3.0 kg were studied, which the left lower lung artery were obstructed by inflating gas of 5F Berman sacculus catheter to set up rabbit pulmonary embolism model, then the gas of sacculus was put out to result in blood reperfusion. The animals were randomly divided into four groups: (1) control group(n=6), (2) sham operation group (sham),(3) embolism 1h group (n=6), (4)embolism 2h group (n=6), Drawing venous blood of all group rabbit at before, embolism 1h, embolism 2h, embolism 2h reperfusion 1h, embolism 2h reperfusion 2h, anticoagulated and centrifuged, then extracted the supernatant. All the plasmas and supernatants were preserved in the -20℃refrigerator. We detected the contents of t-PA and PAI-1 and vWF in plasma by enzyme linked immunosorbent assay (ELISA)。Results: (1) The change of t-PA content in plasma: The mean of t-PA content of lung embolism 1h group was significantly higher than that of pre-embolism, control group and sham group on 1h and had statistical significance(P<0.05). The mean of t-PA content of lung embolism 2h group was higher than pre-embolism, control group and sham group on 1h and 2h and both had statistical significance(P<0.05), but there was no statistical significance between the means of 1h and 2h although 2h was higher than 1h on lung embolism 2h group. (2) The change of PAI-1 content in plasma: The mean of PAI-1 content of lung embolism 1h group was higher than that of pre-embolism ,control group and sham group on 1h, but there was no statistical significance among these groups. The mean of PAI-1 content of lung embolism 2h group was higher than that of pre-embolism ,control group and sham group on 1h and 2h, but there was no statistical significance among these groups. (3) the ratio of t-PA/PAI-1 in plasma: the ratio of t-PA/PAI-1 of lung embolism 1h group was significantly higher than that of pre-embolism, control group and sham group on 1h and had statistical significance(P<0.05). The ratio of t-PA/PAI-1of lung embolism 2h group was significantly higher than that of pre-embolism, control group and sham group on 1h and 2h and both had statistical significance(P<0.05), but there was no statistical significance between 1h and 2h although 2h was higher than 1h on lung embolism 2h group.(4) The change of vWF content in plasma: The mean of vWF content of lung embolism 1h group was significantly higher than that of pre-embolism, control group and sham group on 1h and had statistical significance(P<0.05). The mean of vWF content of lung embolism 2h group was higher than pre-embolism ,control group and sham group on 1h and 2h and both had statistical significance(P<0.05), but there was no statistical significance between 1h and 2h although 2h was higher than 1h on lung embolism 2h group.Conclusion: (1)The experimental animal model of APE owns the advantages in convenient controllability and easy reproducibility. (2) Fibrinolysis system were activated after APE, showing t-PA,PAI-1,t-PA/PAI-1 all increased in the blood.(3) After APE, the level of vWF in plasma gradually increased following time which showed that endothelial cell was injured gradually aggravation. vWF early detection in plasma can monitor the degree of injure of endothelial cell in plasma, so can evaluate pathogenetic condition development.