用放射性血栓肺血栓栓塞症动物模型研究不同尿激酶溶栓方案的效果

目的　比较治疗肺血栓栓塞症 (PTE)时尿激酶 (UK) 2h和 12h溶栓方案的溶栓效果及特点。方法　 17只犬随机分为对照组 5只、UK 2h溶栓组 (UK2h组 ) 6只及UK 12h溶栓组 (UK12h组 ) 6只。利用新鲜放射性血栓PTE模型对两种UK溶栓方案进行对比研究。模型的溶栓率用核医学的感兴趣区技术 (ROI)及离体测定两种方法计算。结果　观察 14h ,利用ROI技术测定的对照组、UK2h组、UK12h组的溶栓率分别为 (6 2± 4 0 ) %、(39 5± 13 9) %、(16 9± 8 9) % ,3组相比 ,UK2h组的溶栓效果明显优于对照组及UK12h组 (P <0 0 1) ,而对照组与UK12h组之间差异无显著性 (P >0 0 5 ) ;UK2h组在溶栓后 4h出现明显的溶栓高峰 ,而UK12h组呈较均匀的缓慢溶解。利用离体法测定的 3组溶栓率分别为 (6 0± 2 7) %、(42 8± 12 4 ) %、(17 7± 9 3) %。两种方法测定的溶栓率有很高的相关性 (r =0 981,P <0 0 1)。结论　对于新鲜血栓 ,尿激酶 2h投药方案较 12h方案的溶栓率高 ,溶栓高峰明显。本实验模型是观察溶栓效果的较好实验方法。

Experimental study of the thrombolytic effects in a canine model of pulmonary thromboembolism induced by autologous radioactive blood clots

OBJECTIVE: To compare the thrombolytic effects of the two dosing regimes with urokinase (UK) in a canine model of pulmonary thromboembolism induced by radioactive blood clots. METHODS: Seventeen dogs were randomly assigned into three groups: the control group, the UK(2h) group (UK infused over 2 hours) and the UK(12h) group (UK given over 12 hours). The thrombolytic differences was investigated among the three groups. Thrombolysis was assessed by continuously counting over both lung fields with single photon emission computed tomography (SPECT) and calculated by regions of interest (ROI) technology and by counting radioactivity in the lung in vitro. The extent of thrombolysis was calculated as the difference between the radioactivity originally incorporated in the clot (decay-corrected) and the radioactivity in the lung in vitro. RESULTS: In three groups, the lysis rates measured by ROI technology were (6.2 +/- 4.0)%, (39.5 +/- 13.9)%, and (16.9 +/- 8.9)% respectively, and (6.0 +/- 2.7)%, (42.8 +/- 12.4)%, and (17.7 +/- 9.3)% by the method in vivo. The thrombolytic ratio of the UK(2h) group was significantly higher than that of the other two groups (P < 0.01), and there was no marked difference between the control group and the UK(12h) group. There was a thrombolytic peak in the UK(2h) group at the first four hours after infusion of agent. CONCLUSIONS: For the fresh thrombi, the UK(2h) regime is superior to the UK(12h) due to its higher thrombolytic ratio and prompt thrombolytic property. The model and methods are highly reliable.