中文摘要：

目的探讨碘-125（^125I）粒子对乳腺癌神经生长因子（NGV）表达及其在抑制肿瘤细胞增殖的作用机制。方法建立人类乳腺癌细胞株（MCF-7）裸鼠皮下移植瘤模型，随机分为8组（对照组为C7、C14、C21、C28组，实验组为T7、T14、T21、T28组）每组6只，对照组植入空白粒子（0Bq），实验组植入^125I粒子（14．8MBq）。观察粒子植入后瘤体生长情况，分别在粒子植入后7、14、21、28d4个时间点处死两组荷瘤裸小鼠。用半定量逆转录-聚合酶链反应（RT—PCR）、免疫组织化学染色方法检测酪氨酸激酶A受体（TrKA）基因其蛋白的表达。结果植入^125I粒子后，实验组肿瘤生长缓慢，肿瘤抑制率为53．27％。粒子植入28d，与对照组比较，实验组中肿瘤组织的NGFmR—NA及蛋白表达明显降低，差异有统计学意义（χ2=37．333，P〈0．01）。结论^125I粒子抑制乳腺癌细胞增殖的机制之-是其抑制乳腺癌细胞NGF基因和蛋白的表达。

英文摘要：

Objective To investigate the action mechanism of iodine-125 inhibiting the growth of tumors cell by suppressing the expression of nerve growth factor （NGF） in breast cancer. Methods The animal models of breast cancer cells （MCF-7） were established by subcutaneously injecting the tumor cells into nude mice. The mice were divided into 8 groups randomly （n =6 in each group） （the control groups contained C7, C14, C21, C28 subgroups; the experimental groups contained T7, TI4, T21, T28 subgroups）. No-load seeds （0 Bq） were implanted into the control groups, and iodine=125 seeds （14. 8 MBq） were implanted into the experimental groups. The size of tumors was measured every two days and their volumes then were calculated. Morphology was examined separately at 7th, 14th, 21st and 28th day after the implantation of iodine-125 seeds. The mRNA and protein expression levels of NGF were detected by using reverse transcription-polymerase chain reaction （RT-PCR） and immunohistochemistry. Results After iodine-125 seeds were transplanted into the tumors of the experimental groups, tumors grew more slowly, and the .tumor inhibition rate was 55.27%. At the 28th day, the mRNA and protein expression levels of NGF in tumors were significantly decreased in experimental groups as compared with control groups （ P 〈 0. 01 ）. Conclusion It is one of important molecular mechanisms to restrain breast cancer with iodine-125 seeds to decrease the expression of NGF in tumor cells.