【摘要】 目的利用⁹⁹锝^m 标记的突触结合蛋白 I-C2A 片段(⁹⁹Tc^m-Syt I-C2A)作为放射性核素显像剂检测体内易损动脉粥样硬化斑块。方法用基因工程制备突触结合蛋白 I-C2A 片段,2-亚氨基噻吩盐酸盐（2-IT）法进行放射性核素标记,制成⁹⁹Tc^m-Syt I-C2A。5只新西兰白兔经胆固醇饲料喂养3个月及腹主动脉内皮损伤形成易损动脉粥样硬化斑块模型,另3只作为正常对照组。静脉注射⁹⁹Tc^m-Syt I-C2A 后进行活体显像,并取出腹主动脉进行体外血管显像和病理检查。结果注射显像剂后2 h,实验组腹主动脉部位放射性摄取明显增高,显影清晰,靶器官/本底（T/B）放射性比值为3.25±0.51。体外显像,腹主动脉亦可见高放射性摄取,与胸主动脉的放射性比值为8.39±1.74。实验组腹主动脉单位质量放射性摄取是正常对照组的12.6倍,是胸主动脉的10.2倍。结论 ⁹⁹Tc^m-Syt I-C2A 能够与易损粥样硬化斑块特异结合,并进行体外成像,有望成为无创性检测动脉易损粥样硬化斑块的有效方法。更多还原

【Abstract】 Objective ⁹⁹Tc^m labeled C2A domain of synaptotagmin Ⅰ (⁹⁹Tc^m_Syt Ⅰ-C2A)is used for noninvasive detection of vulnerable atherosclerotic plaque.Methods Recombinant C2A domain of synaptotagmin Ⅰ,overexpressed in E.Coli,was thiolated with 2-iminothiolane （2-IT） and labeled with ⁹⁹To^m.Atherosclerotic plaques were produced in 5 rabbits by deendothelialization of the abdominal aorta and the rabbits were fed with cholesterol diet for 3 months.Three rabbits not manipulated served as normal controls.All animals were injected with ⁹⁹Tc^m-Syt Ⅰ-C2A and underwent in vivo imaging thereafter.Aortas were then explanted for ex vivo imaging and histological characterization.Results In deendothelized animals,intense radio-uptake in abdominal aorta,showed by γ camera at 2 h after injection,was visualized and T/B was 3.25±0.51 by ROI measurement,quantitative uptake ratio of abdominal aortas with atherosclerotic lesions to thoracic aortas was 8.39±1.74 in ex vivo imaging.The mean uptake in specimens of abdominal aortas with lesions was 12.6-fold higher than in control abdominal aortas,and 10.2-fold higher than in thoracic aortas of deendothelized animals by γ-counter.Conclusion ⁹⁹Tc^m Syt Ⅰ-C2A has a high affinity for vulnerable atherosclerotic plaque and is a suitable a gent for the noninvasive detection of vulnerable atherosclerotic plaque.更多还原