新型近红外荧光探针MHI85在胆道系统成像的实验研究

目的:观察一种新型近红外荧光探针MHI85在器官中的成像特点,寻找特异性的器官成像荧光探针,为手术提供帮助。方法:用海洋光学测量系统检测近红外荧光探针MHI85的吸光度和荧光强度,分析其光学特点。随后将近红外荧光探针MHI85注射到CD-1小鼠体内,4小时后观察小鼠体内腹腔、胆囊和胆管、离体小鼠腹部脏器的近红外荧光成像情况。并测量离体脏器的信号背景比(SBR)。结果:近红外荧光探针MHI85最大吸收峰值和荧光峰值分别在690 nm和713 nm,说明其发光谱在700 nm左右,且成像稳定。利用小动物活体成像系统发现,近红外荧光探针MHI85在小鼠胆囊、胆囊管、左右肝管、肝总管可见明显荧光信号。心、肺、肝、胰、脾、肾、十二指肠、小肠均无荧光信号,而胆囊中可见明显的荧光信号。离体脏器SBR结果显示,胆囊的SBR明显高于其他脏器。结论:近红外荧光分子探针MHI85对胆囊及胆道系统具有良好的靶向性,且成像清晰、定位准确。

Study of a Novel Near Infrared Fluorescence Probe MHI85 in Imaging of Biliary Tract

ABSTRACT Objective: To observe the imaging characteristics of a novel near-infrared fluorescence probe MHI85 in organ, and to search for specific organ imaging, so as to provide help for surgery. Methods: The optical properties of MHI85 was analyzed using an Ocean Spectrophotometer. The biodistribution and targeting was monitored in the CD-1 mouse 4 h post-injection of MHI85 using the Fluorescence-Assisted Resection and Exploration (FLARETM) real-time intraoperative imaging system. And intraoperative imaging of abdominal cavity, gallbladder and biliary tract, resected organs was observed. Signal-to-background ratio (SBR) was calculated by comparing the signals of major organs against surrounding muscle. Results: The emission spectrum of MHI85 was at 700 nm, and imaging was stable. Real-time live-body imaging effectively reported the dynamic process of the biodistribution and clearance of MHI85 in vivo. And the signal of MHI85 targeting on gallbladder, gallbladder duct, left and right hepatic duct and hepatic duct of mouse was obviously strong at 4 h post-injection. There was no fluorescence signal in the heart, lung, liver, pancreas, spleen, kidney, duodenum and small intestine, while there was obvious fluorescence signal in the gallbladder. SBR of isolated organs was measured, indicating that the SBR of gallbladder was significantly higher than that of other organs. Conclusion: Near infrared fluorescence molecular probe MHI85 can be used as targets for imaging of gallbladder and biliary tract system because of its clear imaging and accurate localization.