131I标记C（RGD）2修饰的脂质体的制备及生物分布研究

The Preparation and Biodistribution of 131I Labeled c（RGD）2 Modified Liposomes

目的将c(RGD)2连接于脂质体表面并用放射性核素^131 I进行标记,通过放射性核素生物分布测定探讨脂质体介导的^131 I-c(RGD)2-Lp对比无脂质体介导的^131 I-c(RGD)2脑部摄取情况,为后续将^131 I-c(RGD)2应用于脑胶质瘤的诊断与治疗研究奠定基础。方法将c(RGD)2肽连接于脂质体上[c(RGD)2-Lp]。用放射性核素^131 I进行标记,得到核素探针^131 I-c(RGD)2-Lp,测定该探针在小鼠体内的生物分布,并与未连接脂质体的探针^131 I-c(RGD)2进行对比。结果^131 I-c(RGD)2-Lp主要浓聚在肝、脾、胃等脏器;而^131 I-c(RGD)2主要浓聚在肾、胃等脏器。^131 I-c(RGD)2-Lp在多数器官(除肾以外)中的放射性摄取值均比^131 I-c(RGD)2高。注射^131 I-c(RGD)2-Lp后6h在血液中的放射性摄取值为(3.222±1.205)%ID/g;而^131 I-c(RGD)2的血液放射性摄取值为(0.616±0.277)%ID/g;^131 I-c(RGD)2-Lp注射后6h在脑组织中的放射性摄取值为(0.133±0.053)%ID/g,而^131 I-c(RGD)2的放射性摄取值为(0.023±0.011)%ID/g,两者具有统计学差异(P<0.05)。结论脂质体修饰的c(RGD)2的生物分布与未修饰的c(RGD)2存在很大差异。^131 I-c(RGD)2-Lp的脑摄取值显著高于^131 I-c(RGD)2,并具有较长的血液循环时间,具有进一步应用于脑胶质瘤显像研究的可能性。

Objective To deliver^131 I-c(RGD)2 to brain and establish a knowledge reference for subsequent research on glioma diagnosis and therapy with^131 I-c(RGD)2.^131 I-c(RGD)2 was linked to the surface of liposomes(Lp)and its biodistribution was also measured.Methods The new peptide liposome c(RGD)2-Lp was labeled with radionuclide^131 I to prepare the nuclide probe^131 I-c(RGD)2-Lp.The physicochemical properties of the nuclide probe were identified and its biodistribution in mice was measured and compared with^131 I-c(RGD)2.Results^131 I-c(RGD)2-Lp was mainly concentrated in liver,spleen and stomach,while^131 I-c(RGD)2 was mainly concentrated in kidney and stomach.The radioactivity uptake value of^131 I-c(RGD)2-Lp in most organs(except kidney)was higher than that of^131 I-c(RGD)2.The radioactivity uptake in blood was(3.222±1.205)%ID/g 6h after the injection of^131 I-c(RGD)2-Lp,while the blood radioactivity uptake value of^131 I-c(RGD)2 was(0.616±0.277)%ID/g.The radioactivity uptake in brain was 0.133±0.053%6h after the injection of^131 I-c(RGD)2-Lp,while the radioactive uptake value of^131 I-c(RGD)2 was(0.023±0.011)%ID/g with a significant difference(P<0.05).Conclusion The biodistribution of c(RGD)2 modified by liposomes is very different from that of unmodified c(RGD)2.The brain uptake of^131 I-c(RGD)2-Lp is significantly higher than that of^131 I-c(RGD)2,and^131 I-c(RGD)2-Lp has a longer blood circulation time window,which is more suitable to be applied to the study of brain glioma imaging and therapy.