藤黄酸的标记及其小鼠体内分布实验

通过¹³¹I 标记藤黄酸以分析其在肿瘤细胞中的摄取及动物体内的分布。采用双氧水标记、氯仿萃取，以聚酰胺薄膜为支持介质、氯仿 甲醇(体积比为40∶1）为展开剂，测定标记率及放化纯；分析肿瘤细胞MCF-7对¹³¹I-藤黄酸的摄取；KM小鼠尾静脉注射¹³¹I-藤黄酸（每只185 kBq），于不同时间处死，取各脏器，称重、测量计数率，计算每克组织百分注射剂量率。¹³¹I-藤黄酸标记率达86%，放化纯在1， 4, 20 d分别为97.2%，95.4%，93.3%； MCF-7在30 min时对¹³¹I-藤黄酸摄取率达3.50%，显著高于对Na¹³¹I的摄取（P<0.01）；¹³¹I-藤黄酸在体内分布广泛，以肝、肾和肠为最多，肝中5 min时放射性摄取达25.93%ID/g， 4 h则为5.54%ID/g，而肾中5 min时为6.37%ID/g， 4 h时为2.46%ID/g；甲状腺中的放射性摄取随时间的延长而增加。¹³¹I-藤黄酸标记物稳定；肿瘤细胞MCF-7对¹³¹I-藤黄酸有显著摄取；体内主要通过肝肾代谢。

Radioiodinated of Gambogic Acid and Its Biodistribution in Mice

The preparation of radioiodinated gambogic acid and its cell uptake in MCF-7 and biodistribution in mice were investigated. Gambogic acid was labeled with ¹³¹I using hydrogen peroxide.　The radiolabeled compound was characterized by polyamide TLC, in which the substratum of V(trichoromethane )∶V( methanol ) =40∶1 was used as developing agent. The uptake of ¹³¹I gambogic acid in cancer cells was measured. Biodistribution studies were carried out in KM mice. At different time after radiopharmaceutical i.v. administration (185 kBq ¹³¹I gambogic acid /mouse), the animals were sacrificed. Blood samples and the tissues of interested were collected, weighted and counted. The percent injected dose per gram (%ID/g) was calculated for each sample. The labeling yield of ¹³¹I gambogic acid is 86% and its radiochemistry purity are 97.2%, 95.4%, and 93.3% at 1, 4, and 20 d, respectively. The uptake of ¹³¹I gambogic acid in MCF-7 shows markedly higher compared with Na¹³¹I（P<0.01）.The in vivo biodistribution in mice indicates that ¹³¹I gambogic acid is mainly uptaked in liver, kidney, and intestines. The radioactivity in thyroid increases with time. ¹³¹I gambogic acid is stable and is markedly uptaked in cancer cells MCF-7. In mice, it is mainly metabolized by liver and excreted through kidney.