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目的研究~(131)I标记含精氨酸-甘氨酸-天冬氨酸的小分子环形肽(cRGD肽)在荷瘤小鼠体内的分布与显像,探讨~(131)I-cRGD肽作为肿瘤诊治药物的可能性。方法利用氯胺T法对cRGD肽行~(131)I标记,建立荷黑色素瘤B16动物模型,分别进行体内分布实验、非标记cRGD肽竞争抑制实验及肿瘤显像研究。结果用统计软件SPSS 12.0进行分析。结果~(131)I-cRGD肽的标记率达90%,放射化学纯度达99%;荷瘤小鼠体内分布实验显示:给药后在血液、肾脏、膀胱有较高的放射性分布,小肠、肝脏、肌肉呈低水平放射性分布,24 h肿瘤/肌肉(T/M)放射性比值=6.34,肿瘤/血液(T/B)放射性比值=1.1。显像结果示:静脉注射~(131)I-cRGD肽后1 h肿瘤开始显影,随时间的延长,影像逐渐清晰,24 h时肿瘤显像最清晰。用非标记cRGD肽进行阻断实验,肿瘤的放射性摄取为(0.969±0.151)%/g,与非阻断组(1.40±0.136)%/g比较具有显著性差异。结论应用氯胺T法可以成功完成~(131)I-cRGD肽标记;尾静脉注射~(131) I-cRGD肽后,肿瘤表现为放射性浓聚,肿瘤对~(131)I-cRGD肽的摄取可被非标记的cRGD肽抑制,表明~(131)I-cRGD肽可与肿瘤新生血管αvβ3受体特异性结合,有望成为一种新型的肿瘤诊治药物。
Objective To study the distribution and imaging of ~ (131) I-arginine-glycine-aspartate small molecule cyclic peptide (cRGD peptide) in tumor-bearing mice and to investigate the effect of 131I-cRGD peptide Cancer diagnosis and treatment of the possibility of drugs. Methods The cRGD peptide was labeled with 131I by chloramine T method. The animal model of B16 melanoma was established. The in vivo distribution, non-labeled cRGD peptide competition inhibition and tumor imaging were studied. Results were analyzed using statistical software SPSS 12.0. RESULTS: The labeling rate of ~ (131) I-cRGD peptide was 90% and the radiochemical purity was 99%. The distribution of 131I-cRGD peptide in the tumor-bearing mice showed that it had higher radioactivity distribution in blood, kidney and bladder, Liver, muscle showed low level radioactive distribution, T / M radioactivity ratio was 6.34 and T / B radioactivity ratio was 1.1. The imaging results showed that the tumor began to develop at 1 hour after intravenous injection of ~ (131) I-cRGD peptide. With time prolonging, the image became clearer and the tumor was clearest at 24 hours. The blocking experiment with non-labeled cRGD peptide showed that the radioactivity uptake of tumor was (0.969 ± 0.151)% / g, which was significantly different from that of non-blocking group (1.40 ± 0.136)% / g. Conclusion The ~ (131) I-cRGD peptide was successfully labeled with 131I-cRGD peptide by the chloramine T method. After the 131I-cRGD peptide was injected into the tail vein, the tumor showed radioactive aggregation. The uptake by non-labeled cRGD peptide indicates that ~ (131) I-cRGD peptide can specifically bind to the αvβ3 receptor of tumor angiogenesis and is expected to become a new type of oncology drug.