99mTc-RET的制备及其在正常小鼠体内分布和药代动力学研究#

摘要

目的：研究99mTc-RET(Arg-Glu-Thr)与肺癌细胞结合及其在正常小鼠体内分布和药代动力学。方法：采用99mTc直接法标记RET，行99mTc-RET与非小细胞肺癌细胞A549和H1299的结合实验。正常小鼠尾静脉注射99mTc-RET后不同时间处死，取主要脏器或组织，测定其每克组织百分注射剂量率(%ID/g)。另取尾静脉注射99mTc-RET后不同时间小鼠血液，测量放射性计数并计算药代动力学参数。结果：99mTc直接标记RET的标记率大于90%。99mTc-RET与非小细胞肺癌细胞A549和H1299的最高特异性结合率分别为(3.78±0.29)%和(3.56±0.37)%。体内分布提示99mTc-RET在小鼠血液中清除迅速，2h时放射性仅为注射5min时的26%，肝脏内放射性浓聚较多，且呈缓慢下降，肾脏、心、肺放射性摄取随时间逐渐下降，其余组织放射性呈低水平。结论：99mTcm-RET具有亲肺癌细胞的特性，有可能成为一种亲肺癌肿瘤显像剂。%Objective: To investigate the biodistribution characteristics and pharmacokinetics in nomal mice and uptake in human lung cancer cells of99mTc labeled arginine-glutamic-glutamic(RET).Methods:RET was labeled directly with99mTc The biodistribution of99mTc-RET was studied at 2min,5 min,10min,30min,1h,2h,4h,8h,and 24h,respectively,after intravenous injection in normal mice. At different time points,the mice were sacrificed and organs of interest were excised,weighted and counted by a gamma counter. The organ uptake was calculated as a %ID/g.Results:The radiochemical purity of99mTc-RET were more than 90%,and the specific binding efficiency of99mTc-RET with A549 and H1299 cells was (3.78±0.29)% and (3.56±0.37)%. In the first 24h after injection,the biodistribution in mice showed rapid blood excretion and most of the radioactivity was observed in liver.Conclusion:99mTc-RET can be uptaked in human lung cancer cells,and might possibly become a potential lung cancer imaging agent.