~(64)Cu标记两种奥曲肽类似物的比较

对奥曲肽类似物DOTA-TOC和DOTA-TATE进行~(64)Cu标记,研究多肽用量与~(64)Cu活度比值、pH、反应温度、反应时间对标记率的影响,优化标记条件;考察标记物在10%胎牛血清与生理盐水中的体外稳定性;评价标记物在正常小鼠体内分布情况以及在U87MG人脑神经胶质瘤中的摄取情况。结果表明:~(64)Cu-DOTA-TOC和~(64)Cu-DOTA-TATE标记率均95%;在生理盐水中具有良好稳定性,10%胎牛血清中发生缓慢分解;正常小鼠体内分布实验结果显示,两种标记物在血液中清除较快,主要通过肾、肝代谢,~(64)Cu-DOTA-TATE摄取均高于~(64)Cu-DOTA-TOC;~(64)Cu-DOTA-TOC与~(64)Cu-DOTA-TATE给药后肿瘤PET显像清晰,但~(64)Cu-DOTA-TATE显像效果优于~(64)Cu-DOTA-TOC。研究结果可为其医学应用提供依据。

Comparison of Two Kinds of 64 Cu Labelled Octreotide Analogues

Octreotide analogues DOTA-TOC and DOTA-TATE were labeled with 64Cu . The influences of the ratio of peptide mass to 64 Cu activity ,pH value ,temperature and reaction time on labeling yield were investigated . The optimum labeling was deter-mined .In v itro stability tests in saline and 10% bovine serum had been carried out .Bio-distribution of the two radiolabelled compounds in normal mice and Micro PET imaging in nude mice bearing U87MG tumor had been evaluated .The results showed that the labeling yields of 64Cu-DOTA-TOC and 64Cu-DOTA-TATE were higher than 95% .Two kinds of octreotide analogues labeled with 64 Cu were quite stable in saline and decom-posed slowly in 10% bovine serum at 37 ℃ .Biodistribution results in normal mice showed that two 64 Cu labelled tracers had similar profiles . Both of the compounds washed out from the blood quickly .High uptake of radioactivity in liver and kidneys indicated the tracers were excreted via both hepatobiliary system and renal system .At the same time ,compared to 64Cu-DOTA-TOC , higher radioactivity accumulation of 64Cu-DOTA-TATE in liver and kidneys was observed .Micro PET images of U87MG tumor-bearing nude mice with 64Cu-DOTA-TOC and 64Cu-DOTA-TATE showed the tumors very clearly .The radioactivity uptake of 64Cu-DOTA-TATE in tumor was high-er than that of 64Cu-DOTA-TOC .This work has paved the way for further preclinical and clinical application of 64Cu-DOTA-TOC and 64Cu-DOTA-TATE as PET tumor imaging agents .