叶酸受体型MR对比剂在荷人胃癌裸鼠诊断价值的实验研究

An experimental study of the diagnosing value to nude mice model of transplanted human gastric cancer with folate-receptor MR contrast agent

目的通过探讨以叶酸介导的钆喷替酸葡甲胺(GdDTPAFolate)对裸鼠瘤体信号改变的规律,评价其肿瘤靶向作用。方法将DTPAFolate与氯化钆(GdCl3)在一定条件下等摩尔反应,过滤后得到GdDTPAFolate,将5～6周龄无特定病原体(SPF)级BALB/C裸小鼠皮下接种人胃癌细胞(SGC7901)作为动物模型;将12只荷人胃癌裸小鼠模型采用完全随机法分成实验组(6只)与对照组(6只),前者腹腔注射GdDTPAFolate0.4ml,后者腹腔注射相同剂量并含相同Gd离子浓度的GdDTPA,观察注射前后2组T1WI瘤体信号改变情况。判断指标为对比信噪比(contrastnoiseratio,CNR)。注射后扫描时间点选择为即刻、1、2、3、4、6、12及24h。结果注射对比剂后1h(q1)和2h(q2),实验组裸鼠瘤体信号强度升高明显,与注射对比剂前比较,差异有统计学意义(以计算值CNR为判断指标:q1=5.80,q2=4.64,P值均<0.05);对照组注射对比剂后1h(q1)和2h(q2),裸鼠瘤体信号变化与注射对比剂前比较,差异无统计学意义(以计算值CNR为判断指标:q1=0.64,q2=1.19,P>0.05)。结论GdDTPAFolate对裸鼠胃癌模型(SGC7901)肿瘤具有一定的靶向性。

Objective To evaluate the tumor targeting characteristic by observing signal varying of human gastric cancer transplanted nude mice （SGC-7901） using Folate-Receptor MR contrast agent.Methods As a Folate-Receptor MR contrast agent, Gd-DTPA-Folate was obtained by conjugation of DTPA-Folate and GdCl3 under specific conditions. Nude mice of subcutaneously transplanted human gastric cancer（SGC-7901） were used as animal models, 12 mice were divided into experimental group（ n = 6） and control group（ n = 6 ） randomly. Both were injected with Gd-DTPA-Folate and Gd-DTPA （contained same gadolinium） via abdominal cavity respectively. Tumor signal varying was observed by Tl WI after injection of contrast agent immediately, 1,2,3,4,6,12 and 24 h, and tumor signal changing of experimental group was compared with that of control group. CNR （contrast noise ratio） was regarded as evaluating mark. Results Tumor signal intensity of experimental group was increased evidently between 1 -2 hours after injecting Gd-DTPA-Folate. Comparison with pre-injection, there was a significant difference （evaluating mark is CNR：q1 = 5.80, q2 = 4.64 ; P 〈 0.05 ） for experimental group, whereas there was no statistic difference for control group after injecting Gd-DTPA during the same period of studying（ evaluating mark was CNR： q1 =0. 64,q2 = 1.19, P 〉 0. 05 ）. Conclusion Gd-DTPA-Folate shows definite characteristic of tumor targeting effect to nude mice of subcutaneously transplanted human gastric cancer （ SGC-7901 ）.