中文摘要：

目的探讨放射性碘131^（131I）标记基因重组鞭毛蛋白（rFliC）在乳腺癌荷瘤小鼠体内的生物分布特征及意义。方法逆转录聚合酶链反应（RT-PCR）、蛋白质印迹法（Western blot）及免疫荧光检测人乳腺腺癌细胞系（MCF-7）中rFliC的受体TLR5的表达;四氯二苯基苷脲（Iodogen）法^131I标记rFliC,检测其放射化学纯度、稳定性、细胞摄取状况;制备MCF-7荷瘤鼠,注射^131I-rFliC后,观察其生物学分布及肿瘤靶向性。结果①MCF-7表达TLR5的mRNA及蛋白;随着rFliC浓度的增加,TLR5 mRNA及蛋白表达逐渐减弱;②^131I-rFliC标记率达95.19%;放射化学纯度为96.46%;在血清中稳定性高,可被MCF-7稳定摄取;③^131I-iFliC主要经肝肾代谢,肿瘤靶向性明显,24 h靶/肌肉（T/M）放射性比值为7.09,可获得清晰放射自显影像。结论^131I-rFliC肿瘤靶向明显,有望作为一种新型分子探针监测乳腺癌的发生发展。

英文摘要：

Objective To investigate the biodistribution and significance of 131I- rFliC in breast cancer-bearing mice. Methods （1） The expression of TLR5 was assayed by the immunofluorescence method,RT-PCR and Western blot. （2） rFliC was labeled by 131I and the radiochemical purity, stability, cell uptake and efflux of 131 I- rFliC were identified. （3） MCF-7 bearing mice were prepared and injected with 131 I- rFliC. The biodistribution of 131 I- rFliC and tumor targeting were analyzed. Results （1） MCF-7 could express TLR5 at the mRNA and protein levels. The expression of TLR5 was down-regulated by rFliC with a dose-dependem manner. （2） The labeling efficiency of 131I-rFliC was 95. 19% and the radiochemical purity was 96.46%. 131I-rFliC was more stable in serum and could be absorbed by MCF-7 stably. （3） 24 h after injection with 131I-rFliC, T/M ratio was 7.09, and tumor tissue appeared clearly with the autoradiography. Con- clusion Tumor-targeting of 131I -rFliC is obvious, and it may become a new molecular probe for the diagnosis and therapy of breast cancer.