菁类染料用于棕色脂肪组织荧光显像的生物学评价

Biological evaluation of cyanine dyes for fluorescence imaging of brown adipose tissue

目的筛选靶向棕色脂肪组织的菁类染料,利用荧光活体成像系统建立体内实时监测棕色脂肪组织(BAT)的分析方法。方法考察菁类染料Ⅰ、Ⅱ、Ⅲ在不同溶剂中的光学性质;通过荧光显像实验考察荧光染料对小鼠体内BAT的靶向能力、代谢趋势和分布;通过消解实验考察荧光染料的靶标。结果荧光染料Ⅰ、Ⅱ、Ⅲ的发射波长均大于650 nm,处于近红外光区;染料Ⅰ可显像正常小鼠体内BAT,肩胛区荧光图像呈标志性的三角形,且体内代谢速度较快;消解实验进一步确认了染料Ⅰ主要聚集在BAT。结论筛选了靶向体内BAT的菁类染料,其中,荧光染料Ⅰ能无创显像活体小鼠体内的BAT,可为BAT的相关研究提供简便的显像分析工具。

OBJECTIVE To screen cyanine dyes that target brown adipose tissue( BAT) and to establish analytical method for real-time in vivo monitoring of brown adipose tissue by fluorescence imaging. METHODS Optical properties of cyanine Ⅰ,Ⅱand Ⅲ in different solvents were evaluated. In vivo fluorescence imaging and BAT digestion was performed to investigate probe localization and distribution in vivo. RESULTS Cyanines Ⅰ,Ⅱ and Ⅲ showed emission wavelengths above 650 nm that fell in the near-infrared range. Cyanine I exhibited preferred distribution in BAT with good image detail of BAT anatomy. Ex vivo digestion further confirmed that main accumulation of cyanine I was in brown adipocytes. CONCLSION Cyanine Ⅰ has favorable properties for BAT imaging,and may serve as an effective tool for BAT-related research.