Objectives: To study the functional changes and the significance of coagulation, fibrinolysis and pulmonary vascular endothelium before and after experimental pulmonary thromboembolism in rabbits.
Methods: Rabbit pulmonary thromboembolism models by injection of auto-blood clots into femoral vein were used to observe the dynamical changes of activity of coagulation and fibrinolysis and endothelin-1 (ET-1), nitrogen monoxide (NO), von Willebrand factor (vWF) in blood.
Results: Petechial and patchy hemorrhages were observed on the surfaces of embolic lungs. The injected blood clots and secondary thrombosis in the pulmonary arteries, inflammatory cell infiltration around alveoli, local hemorrhages in the alveoli and interstitial tissue could be found by microscopy. The concentration of D-dimer, ET-1 and vWF in blood were significantly elevated, and the tissue-type plasminogen activator (t-PA), NO and antithrombin III (AT-III) decreased significantly after embolism (P < 0.05). After administration of urokinase, the pathological injuries relieved, and the concentration of D-dimer was higher at 1 h and 2 h after embolization than that before embolization (P < 0.05), and reduced to the level of pre- embolization at 4 h after embolization. The levels of t-PA, NO and AT-III after embolization were lower than those before embolization (P < 0.05). The level of ET-1 was higher at 2 h after embolization (P < 0.05) and reduced to the level of pre-embolization at 4 h.
Conclusions: PTE has important impacts on coagulation, fibrinolysis and pulmonary vascular endothelial function. Thrombolysis with urokinase could keep the balance between coagulation and fibrinolysis and protect pulmonary vascular endothelial function.