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[摘要]
目的 研究同位素99Tcm示踪血栓技术在家兔脑卒中模型上的应用,并动态示踪观察重组组织型纤溶酶原激活剂(rt-PA)对血栓的溶解效果。方法 将新鲜洗脱的放射性高锝酸钠(5 mCi/2 mL,92.5 MBq/mL)0.5 mL与5 mg/mL氯化亚锡30 μL充分混合成示踪标记液;分别向全血、红细胞、血浆中加入20 μL示踪标记液进行同位素标记,加入50 μL CaCl2(0.5 mol/L)与牛凝血酶(50 IU/mL)混合物,迅速吸入聚乙烯塑料管(PE80)中,37℃固化2 h后取出血栓,分割成10 mm的示踪血栓,并计算标记率。采用经兔颈外动脉逆向颈内动脉插管方法,注射示踪血栓栓塞大脑中动脉,制备脑卒中模型,用γ计数仪在兔头部测定放射性强度即每分钟计数(Counts Per Minute,CPM)的动态变化,并观察临床等效剂量工具药rt-PA4.5 mg/kg的溶栓效果。结果 全血血栓标记率为53.5%,红细胞与血浆标记比率为4.5∶1,家兔大脑中动脉血栓栓塞后CPM明显增加,约为本底的5.1±1.3倍,表明模型制备成功,检测可靠。静脉给予工具药rt-PA能产生显著的渐进性溶栓效果。结论 锝标记主要以标记红细胞为主,对血浆及纤维蛋白原影响较小。99Tcm示踪血栓技术制备的脑卒中模型,分离区明显,模型制备成功、指标检测科学,模型对药物疗效应答能力的反应稳定、可靠。
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[Abstract]
Objective To study the application of 99Tcm in rabbit cerebral thromboembolic stroke and thrombolysis effect of recombinant tissue plasminogen activator (rt-PA). Methods The 0.5 mL radioactive pertechnetate sodium (specification: 5 mCi/2 mL and radiation intensity 92.5 MBq/mL) was combined with 30 μL stannous chloride (5 mg/mL), and the 20 μL mixture was joined to whole blood, red blood cells, and plasma for labelling. Then 50 μL CaCl2 (0.5 mol/L) and bovine thrombin (50 IU/mL) were doped in mixture, and rapidly sucked into a polyethylene plastic pipe (PE80). Thrombus was formed for 2 h at 37 ℃ and cut into small pieces of 10 mm. Autologous blood clots combined with 99Tcm from external carotid artery were injected to internal carotid artery of rabbit, the radioactivity (counts per minute, CPM) was measured by gamma counting instrument, and the improvement of rt-PA 4.5 mg/kg (clinical equivalent dose) on this model was observed. Results After thromboembolism, CPM increased approximately by (5.1±1.3) times, which suggested that the model was reliable. The rt-PA 4.5 mg/kg had significant progressive thrombolysis effect. Conclusion 99Tcm tracer technology could be applied to rabbit cerebral stroke model, which is stable and reliable
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