异硫氰酸荧光素-CSNRDARRC分子探针的荧光特性及其在体标记膀胱癌原位移植瘤的靶向性研究

Experimental study on the characters of the FITC-CSNRDARRC molecular probe and its targeted ability for orthotopic transplanted tumor of bladder cancer in vivo

目的探讨异硫氰酸荧光素（fluoresceinisothiocyanate，FITC）．CSNRDARRC分子探针的荧光特性及其在体标记膀胱癌原位移植瘤的靶向性。方法2013年7月至2014年6月采用分光光度仪及分子成像仪对FITC—CSNRDARRC探针的荧光特性及稳定性进行体外检测，确定其在体标记肿瘤的最佳浓度及成像时间窗。选取BALB—C系裸鼠30只，分成移植瘤组20只和正常组10只；其中正常组再分为结扎双侧输尿管组（A组）和未结扎输尿管组（B组），每组各5只。手术方法：建立人膀胱癌细胞株BIU-87膀胱癌原位移植瘤模型。建模2周后，30只裸鼠均经尾静脉注射最佳浓度的FITC-CSNRDARRC分子探针0．2ml，采用光学分子荧光成像仪分别检测注射后30min以及1、2、4、12h裸鼠的心、肺、肝、脾、双肾、膀胱及膀胱癌原位移植瘤中的分子影像，并测量其平均灰度值。结果FITC．CSNRDARRC探针220μmol／L为最佳注射浓度，循环4h为最佳时间窗，光照和温度对FITC—CSNRDARRC探针的荧光信号强度影响不大。30只裸鼠经尾静脉注射FITC—CSNRDARRC后，随着时间的延长，肿瘤组织荧光信号逐渐增强，在4h时荧光信号强度达到最强，1、2、3、4、5、6、8、12h的平均灰度值分别为74．22、76．20、80．11、89．38、83．29、85．10、81．22、83．01；正常组织荧光信号随时间延长逐渐减弱。注射4h时，A组除肝脏、胆囊有散在的荧光信号外，其余组织几乎看不到荧光信号；B组的胆囊和膀胱内可见较强的荧光信号。结论体外FITC—CSNRDARRC分子探针的荧光特性受浓度的影响，在体标记肿瘤的最佳浓度为220μmol／L，成像理想时间窗为4h；体内FITC-CSNRDARRC分子探针能明显富集在肿瘤组织。

Objective To investigate the characters and targeted ability of FITC-CSNRDARRC molecular probe in labeling orthotopic transplantation tumor of bladder cancer in vivo. Methods From July 2013 to June 2014, the stability and characters of FITC-CSNRDARRC molecular probe were detected by speetrophotometer and molecular imaging and the optimum concentration and imaging time window were determined. 30 BALB-C nude mice were randomly divided into experimental group （n = 20 ） and control group （ n = 10 ）. In control group, 5 of them （ group A） were ligated bilateral ureter, others （ group B ） were not. We established orthotropic transplanted bladder tumor （BIU-87） model by operation. And 0.2 ml probes （220 p.mol/L） was then injected intravenously in all mice after 2 weeks. We obtained images and analyzed average gray value of the heart, lung, liver, spleen, bilateral kidney and orthotropic transplantation bladder tumor by using optical probe molecule fluorescence imaging system after 30 rain, 1 h ,2 h ,4 h and 12 h, respectively. Results After injected the FITC-CSNRDARRC molecular probes intravenously at 220μmol/L, the fluorescence signal of tumor tissue strengthened gradually. The optimal imaging time window was 4 hours after injection. The illumination and temperature had little effect on the fluorescence signal. With the time passing after injection, the intensity of florescence signal progressively increasing, which reached the peak at 4 h. The average gray value of tumor tissue at 1 h,2 h,3 h,4 h,5 h,6 h,8 h,12 h were 74. 22,76.2,80. 11,89.38,83.29,85. 1,81.22,83.01, respectively. The fluorescence signal of normal tissue weakened gradually with the passage of time. Only liver and gall bladder could notice the fluorescence signal 4 hours after injection in group A. However, the relatively strong fluorescence signal could be found in liver and gall bladder in group B. Conclusions The characters of fluorescence probe are affected by its concentration. Its optimal concentration of labeling tumor is 220 μmol/L. The optical imaging time window was about 4 h after intravenous injection. The FITC-CSNRDARRC molecular probe can specifically bound to orthotopic transplanted tumor of bladder cancer in vivo.