NGR短肽的188Re标记及其在荷瘤裸鼠体内的生物分布和SPECT显像

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 Immunodeficiency，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。

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

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.