γ计数仪测定99mTc-3PRGD2在肺癌肿瘤模型小鼠中的组织分布

摘要

目的 建立一种由γ计数仪测定放射性肿瘤显像剂锝[99mTc]标记的联肼尼克酰胺-3聚乙二醇-精氨酸-甘氨酸-天冬氨酸环肽二聚体(99mTc-3PRGD2)的方法,并研究肺癌肿瘤模型小鼠注射该显像剂后体内组织分布特点.方法 设置4个正常分布组和1个冷肽封闭组(对照组),均经由尾静脉注射该显像剂(8μg/kg)于肺癌肿瘤模型小鼠,正常分布组分别于0.5、1、2和4 h取其组织,对照组在注射放射性药物前0.5 h,腹腔注射0.2 ml 3PRGD2生理盐水溶液(浓度2.5 mg/ml),并于2 h取其组织,肿瘤及其他组织使用γ计数仪检测其放射强度.结果 模型小鼠的肿瘤中放射性药物含量很高,脑组织药物透过量极少;肾和膀胱放射性都很高,提示该药物可能主要经肾排泄;对照组小鼠除肾和膀胱外,其他组织的放射性均很低.结论 该显像剂具有肿瘤靶向性;冷肽可竞争性地抑制99mTc-3PRGD2与整合素αvβ3受体结合.%Objective To establish a quantitative analysis method for determining 99mTc-HYNIC-PEG4-E[PEG4-c(RGDfK)]2 (99mTc-3PRGD2,a radioactive tumor agent)byγcounter, and to investigate the distribution of 99mTc-3PRGD2 in mice bearing with lung carcinoma xenograft. Methods The mice were divided into 4 normal groups and one blocking peptide group(control group). The 99mTc-3PRGD2(8μg/kg)was injected to mice bearing with lung carcinoma xenograft through the tail intravenous administration. Tissues of the normal mice were taken at 0.5,1,2 and 4 h. The control group were treated by 3PRGD2 and 99mTc-3PRGD2. The control mice were injected with the 3PRGD2 saline solution(2.5 mg/ml,0.2 ml)at 0.5 h earlier before the injection of 99mTc-3PRGD2. The tu?mor and organ tissues of the control mice were taken at 2 h. The radioactivity was detected by Gamma Counter. Results The radioac?tivity of 99mTc-3PRGD2 detected was high in the tumor and very low in brain. In addition,high radioactivity in kidneys and bladder sug?gested that the drug excreted by renal. Conclusion The results proved that the blocking peptide can competitively inhibit the combi?nation of 99mTc-3PRGD2 and integrinαvβ3 receptors.