叶酸受体靶向磁共振对比剂157Gd-DTPA-Folate增强裸鼠肿瘤信号的初期评估

评估移植人胃癌细胞(SGC-7901)的裸鼠注射叶酸受体靶向对比剂钆-二亚甲基三胺五乙酸-叶酸(gadolinium-diethylenetriaminepentaacetic acid-folate,Gd-DTPA-Folate)后磁共振信号的变化情况.通过将叶酸与二亚甲基三胺五乙酸(DTPA)连接后,再与GdCl3反应合成Gd-DTPA-Folate.移植人肿瘤细胞的裸鼠随机分成实验组及对照组.试验组小鼠腹腔注射0.4mL的Gd-DTPA-Folate,对照组小鼠注射等摩尔量Gd3 的Gd-DTPA.注射对比剂前和注射对比剂后即刻、1、2、3、4、6、12和24 h进行MR扫描,观察肿瘤的信号特征.试验组注射对比剂后即刻、1、2、3h的肿瘤信号强度都显著高于注射前的信号.注射后1小时出现最大差异,差异可维持3小时(P＜0.05).对照组小鼠,除了注射后即刻和1h,其他注射对比剂后任何时间点的肿瘤信号强度与注射前没有统计差异.与Gd-DTPA相比,Gd-DTPA-Folate可延长移植人胃癌肿瘤细胞的裸鼠的肿瘤信号增强时间,有可能成为一种有潜力的叶酸受体靶向的磁共振对比剂.

Preliminary evaluation of 157Gd-DTPA-folate as a folate-receptor-targeted magnetic resonance contrast media for enhancing tumor signal intensity of athymic mice

The aim of this study was to evaluate magnetic resonance (MR) signal variations of transplanted human gastric adenocarcinoma cells (SGC-7901) in athymic mice after the administration of folate-receptor- targeted MR contrast agent gadolinium- diethylenetriaminepentaacetic acid-folate (Gd-DTPA-Folate). A paramagnetic contrast agent, Gd-DTPA-Folate was synthesized by conjugating folic acid to diethylenetriaminepentaacetic acid (DTPA) , then reacting with GdCl3. The athymic mice with a human tumor cell implant were divided into either the study group or the control group. The 0.4mL Gd-DTPA-Folate was injected into the abdominal cavity of the mice in the study group, while the control group received Gd-DTPA with equivalent Gd3+. The signal features of the tumor precontrast and postcontrast were observed on TtW] MR scanning was carried out at 0, 1, 2, 3, 4, 6, 12 and 24 hour post-injection. The tumor signal intensity at 0, 1,2 and 3h postcontrast in the study group was significantly higher than that of precontrast. The biggest difference appeared at one hour and the difference was retained about 3 hours. In the control group, there was no statistical difference between the tumor signal intensity at any time point post injection and that of prior to injection except 0 and 1h postcontrast. Gd-DTPA-Folate can produce a sustained increase in the signal intensity of the transplanted human gastric adenocarcinoma cells in athymic mice, thus, it may become a promising folate-receptor-specific magnetic resonance contrast media.