NGR短肽的^(188)Re标记及其在荷瘤裸鼠体内的生物分布和SPECT显像

Labeling of NGR Peptide With ^(188)Re and Its Biodistribution and SPECT Imaging in Tumor-bearing Nude Mice

采用188Re标记含有天冬酰胺、甘氨酸、精氨酸(Asn-Gly-Arg,NGR)序列的肿瘤血管靶向性短肽,得到188Re-NGR,观察了188Re-NGR在荷HepG2肝癌细胞严重联合免疫缺陷(Severe Combined Immunodefi-ciency,SCID)裸鼠肿瘤模型中的生物分布,并对其进行了SPECT显像。结果显示,188Re-NGR的标记率>85%,放化纯度>90%。188Re-NGR在肿瘤模型鼠体内的生物分布显示,注射188Re-NGR后12 h,肿瘤放射性摄取达最高,为(4.62±0.71)%ID/g,24 h时仍有(2.01±0.38)%ID/g,说明标记物在肿瘤内停留时间较长;竞争性抑制组中,12 h肿瘤放射性摄取为(1.43±0.61)%ID/g,明显低于实验组。肿瘤与肌肉组织的放射性摄取比(T/NT)12 h为4.76。注射后1 h肿瘤可显像,4~8 h显像逐渐清晰,12 h时更为清晰。以上结果提示,188Re-NGR具有良好的肿瘤血管靶向性。

To evaluate its radiochemical characteristics,biodistribution and imaging for nude mice bearing HepG2,188Re-NGR was prepared directly with 2-mercapto-ethanol as reductant and sodium gluconate as middle ligand.The labeling yield of 188Re-NGR was more than 85%,and the radiochemical purity（RCP） was more than 90%.In vivo,188Re-NGR can specifically bind with tumor.The tumor uptake was（2.84±0.51）%ID/g at 1 h after injection,the uptake was（4.62±0.71）%ID/g at 12 h and remains（2.01±0.38）%ID/g for 24 h,the contrl group was（1.43±0.61）%ID/g.The ratio of tumor to muscle was 4.76 at 12 h.The xenografted tumor became visible at 1 h and was the most clearly at 12 h.The results showed that NGR had the function of good targeting.