【摘要】 目的　探讨以凝血酶为靶，重组水蛭素（ｒＨ）为配基进行血栓显像的潜在价值。方法　氯胺Ｔ法制备１２５ＩｒＨ，采用体外放射配体结合法分析ｒＨ对凝血酶纤维蛋白复合物的亲和、定量关系和时间反应动力学。亚氨基噻吩盐酸盐修饰法制备９９ＴｃｍｒＨ，进行小鼠体内分布测定及犬动、静脉血栓模型显像。结果　ｒＨ 不能直接与纤维蛋白原结合，当凝血酶与纤维蛋白形成复合物后才能与其形成三元复合物，且这种结合呈高亲和、特异和可逆性。９９ＴｃｍｒＨ 在小鼠心、脑、肝、脾、肺摄取低，肾摄取高，１５ ｍｉｎ 达（６４－７２４±５－０４２） ％ＩＤ／ｏｒｇａｎ，血清除迅速。犬股动脉血栓于４５ ｍｉｎ 可清晰显影，靶／ 本底（Ｔ／Ｂ） 比值为１－４７。静脉血栓于注药后３０ ｍｉｎ 就出现浓聚，并随时间延长血栓显影更清晰，１ ｈ Ｔ／Ｂ比值为１－５３。结论　９９ＴｃｍｒＨ 有望成为１ 种新的较理想的血栓示踪剂更多还原

【Abstract】 Objective To assessthe ability ofthe directthrombin (Th) inhibitor,recombinant hirudin (rH) as a new thrombusimagingligand- Methods 125I rHwas prepared by chloramine Tmethod,99Tcm rHby modified 2 iminothiolane method- The affinity ofrHto Th fibrin complex wasanalyzed bythecompetitiveradioas sayin vitro,the kinetics ofthe rH Th fibrin complex formation was studied too- Biodistribution of 99Tcm rHin mice wasdetermined andthrombusimaging was performedin dogthrombosis model- Results TherHcould only bind with Th fibrin complex,butnotdirectly withfibrinogen andthe binding wasoffairly high specificity and a vidity- The biodistribution studyin mice demonstrated thatrH was excreted from kidneys [(64-724 ±5-042)% ID/orgen within 15 min afterinjection] and there waslow uptakein heart,brain,liver,spleen and lungs- In SPECTimaging,allthrombi were clearly visible,arterialthrombi were seen clearly within 45 min afterinjection (T/B= 1-47) andfadedawayslowly,venousthrombi werealsoseen within30 minafterinjection and quantitative imagingratios ofthethrombustothe contralateralvesselincreased withtime (T/B= 1-53in 60 min)- Conclu sions Allthese resultsindicatethatTh probablycan beregarded asthetargetor markerin diagnosisofthrombus formation and rHcan be used asa newligandinthrombusimaging-更多还原