99~Tc^m-HYNIC-Annexin V荷瘤小鼠肿瘤细胞凋亡显像研究

The study on tumor cell apoptotic imaging in vivo with ~99Tc^m-HYNIC-Annexin V in mice tumorbearing

目的研究^(99)Tc^m-联肼尼克酰胺-膜联蛋白 V(HYNIC-Annexin V)的制备及其在荷瘤小鼠体内生物分布特性和活体显像。方法用双功能螯合剂法,以^(99)Tc^m 标记 Annexin V,经高效液相色谱仪分离纯化并检测产物的标记率、放化纯及稳定性。建立荷 S180肉瘤小鼠模型,于20～25g/只昆明种小白鼠右前腋皮下接种 S180肉瘤细胞1周。荷瘤小鼠在环磷酰胺腹膜内化疗72 h 后,尾静脉注射7.4 MBq(200μl)^(99)Tc^m-HYNIC-Annexin V,分别于5、30 min 和1、3、6 h 进行显像和体内生物分布测定。实验结果应用 SPSS 12.0统计软件进行分析。结果 ^(99)Tc^m-HYNIC-Annexin V 的标记率达95%,放化纯为99%。荷瘤小鼠注射^(99)Tc^m-HYNIC-Annexin V 后6 h 显像,可见肿瘤组织放射性浓聚明显异常。体内生物分布实验示,注射显像剂后6 h 肿瘤组织的放射性摄取最高[每克组织百分注射剂量率(%ID/g)为1.59±0.44],与其他时相比较,差异有显著性(P<0.05)。^(99)Tc^m-HYNIC-Annexin V 主要浓聚于肾、肺和肝,经肾脏排泄;其在血液中清除速度快,注射后30 min,血液放射性摄取[(1.59±0.50)%ID/g]较注射后5 min 时[(8.85±2.65)%ID/g]减少80%(P<0.05)。注射显像剂后6 h,肿瘤/肌肉放射性摄取比值(3.73±1.42)高于肿瘤/血液(2.80±0.54)。结论 ^(99)Tc^m-HYNIC-Annexin V 活体细胞凋亡显像可应用于荷瘤小鼠模型,其临床应用有待进一步研究。

Objective To investigate the imaging in vivo and biodistribution characters of ^99Tc^m-hydrazino-nicotinamide （ HYNIC）-Annexin V as tumor cell apoptotic imaging agent in mice tumor-bearing. Methods Annexin Vwas labeled with ^99Tc^m using HYNIC method, then isolated and identified with high performance liquid chromatography（HPLC）. One week after being inoculated with S180 sarcoma in right upper limbs, the mice were randomized to receive a single dose of cyclophosphamide（ 150 mg/kg, intraperitoneally）. After having received cyclophosphamide 72 h, the mice were injected with ^99Tc^m-HYNIC-Annexin V through tail vein. The images and radioactivity in tissues were obtained at 5 , 30 min and 1, 3, 6 h postinjection of imaging agent, respectively. The data of radioactivity in tissues were analyzed by the statistic software of SPSS 12.0. Results The labeling efficiency and radiochemical purity of HYNIC-Annexin V labeled with ^99Tc^m- reached 95% and 99% , respectively. Abnormal and marked uptake of radioactivity was found in tumor tissue of mice tumor-bearing at 6 h postinjection. Compared with the retention percentages of radioactivity （ % ID/g） in tumor tissue at different time points postinjection, the radioactivity in tumor tissue at 6 h ＇after injection of imaging agent [ （ 1.59 ±0.44） % ID/g] was highest, there were significant differences among them（ P 〈 0.05）. The ^99Tc^m-HYNIC-Annexin V accumulated in kidney, lung and liver. It was cleared quickly through blood. In comparison with activity [ （8.85 ± 2.65 ） % ID/g] at 5 min postinjection, 80% of initial activity reduced in blood at 30 min[ （ 1.59 ±0.50） %ID/g]. The ratio of tumor/ muscle （ 3.73 ± 1.42 ） was higher than that of tumor/blood （ 2.80 ± 0.54）. Conclusion ^99Tc^m-HYNIC-Annexin V appeared to be a potential and useful molecular probe of tumor cell apoptosis.