99~Tc^m-SytI-C2A突变体蛋白在心肌缺血再灌注诱导的心肌细胞凋亡显像中的应用  

Application of (99)~Tc^m-Syt I-C2A in apoptosis imaging of cardiocytes based on myocardial ischemia-reperfusion

作　　者：钱丽娟[1] 周俊东[1] 方纬[2] 吴锦昌[1] 

机构地区：[1]南京医科大学附属苏州医院心内科,江苏苏州215001 [2]阜外心血管病医院核医学科,北京100037

出　　处：《江苏实用心电学杂志》2012年第2期82-84,87,共4页Journal of Practical Electrocardiology JS

基　　金：南京医科大学科技发展基金资助项目(NY0714);苏州市科技局社会发展基金资助项目(SZD0894);苏州市科技计划兴卫青年科技计划资助项目(SWKQ0818)

摘　　要：目的探讨99Tcm标记突触结合蛋白I-C2A片段突变体(99Tcm-SytI-C2A-G4C)在心肌凋亡显像中的应用。方法 (1)采用亚锡还原法制备99Tcm-SytI-C2A-G4C。99Tcm-SytI-C2A-G4C经纯化后通过纸层析法测定放化纯;细胞结合实验测定99Tcm-SytI-C2A-G4C与磷脂酰丝氨酸的结合能力。(2)选用5头小猪制备心肌缺血-再灌注损伤模型,静脉注射99mTc-Cyt-C2A-G4C2h后进行图像采集,计算心肌异常高放射性区/本底(T/B)比值;同时使用原位末端标记法(TUNEL)分析损伤心肌中细胞凋亡情况。结果 (1)标记后的99Tcm-SytI-C2A-G4C放射化学纯度为(96.42±0.76)%;(2)99Tcm-SytI-C2A-G4C与喜树碱处理组细胞结合测定的放射性计数是未处理组细胞的5.23±0.38倍;(3)99mTc-Cyt-C2A-G4C注射后2h,心肌部位可见明显的局部放射性异常浓聚,T/B比值为3.40±0.43;高放射性心肌组织标本,TUNEL染色亦可见大量黄染的凋亡细胞。结论 99Tcm-SytI-C2A-G4C可用于心肌细胞凋亡显像。Objective To investigate application of mutation protein of C2A domain of synaptotagmin I （ Syt I- C2A-G4C） labeled with technetium in myocardial apoptosis imaging. Methods （ 1 ） The C2A domain of Syt I was labeled with ^99Tc^musing reduction photometry of Tin chloride. Radioehemical purity was determined with thin layer chromatography. The binding activity with phosphatidylserine of radiolabeled protein was assessed using cell bind- ing experiment. （2） Myocardial ischemia-reperfusion models were produced in 5 pigs. SPECT images were ac- quired at 2h after post injection of 99m^T^c-Cyt-C2A-G4C via the tail, and the ratio of target/background was also cal- culated using region of interest （ROI） method. Apoptosis in the ischemic myocardium was assessed using terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. Results （ 1 ） The radiochemical puri- ty of 99^Tc^m-Syt I-C2A-G4C was（96.42 ± 0.76）%. （2） The radioactivity in the camptothecin-treated group was （ 5.23 ±0. 38 ） folds higher than that of non-treated viable control group. （3） At 2 h post-injection of the radiotrac- er, the focal uptake of radioactivity was observed at the ischemic myocardium areas, and T/B ratio was 3.40 ± 0.43. Myocardial apoptosis was confirmed by TUNEL assay in the ischemic myocardium with high radioactivity. Conclusion ^99Tc^m-Syt I-C2A-G4C should be a potential radiotracer for imaging of myocardial apoptosis.

关 键 词：心肌缺血再灌注 凋亡显像 突触结合蛋白I 锝 

分 类 号：R542.2[医药卫生—心血管疾病]