[The significance of thrombosis after experimental pulmonary thromboembolism]

To study the significance of thrombosis after experimental pulmonary thromboembolism (PTE).

Acute PTE models of rabbits were established with injection of autologous blood clots (0.04 g/kg) stabilized in a temperature-controlled (70 degrees C) of distilled water for 10 minutes through the femoral vein, then the regulation of thrombosis was explored at dissection and upon microscopic examination after PTE. Moreover, the coagulability of blood and the plasma level of thromboxane A2(TXA2) and endothelin (ET) were examined.

Thrombotic propensity was found at 1 h, and fresh thrombosis started to form at 24 h following clots infusion. Emboli were completely or partly dissolved at 5 d and organized at 10 and 14 d after clots infused. Prothrombin time was significantly lower [(7.15 +/- 0.06)s], and fibrinogen was higher [(5.86 +/- 1.50) g/L] at 24 h post-clots, compared with pre-clots [(7.34 +/- 0.19)s, (3.37 +/- 1.02) g/L] (P < 0.05). Venous plasma level of TXA2 began to increase at 5 min [(2.5 +/- 0.7) micrograms/L] and continued to rise to its maximum at 15 min [(2.5 +/- 0.6) micrograms/L], then declined at 60 min after clots infusion. The level of ET in both arterial and venous blood increased at 5 d post-clots [(0.84 +/- 0.15) micrograms/L and (0.23 +/- 0.05) micrograms/L] separately, while most of emboli resolved.

There is thrombus formation after autologous-blood-clots-induced PTE. Furthermore, thrombus formation, fibrinolysis and organization may always interact on each other consistently, and control the pathogenesis of PTE. Abnormalities of ET metabolism occur after PTE and the major mediator of TXA2 plays an important role in the early phase of PTE.