人视网膜色素上皮细胞对吲哚青绿的吸收与代谢

The absorption and metabolism of indocyanine green in human retinal epithelial cells

目的 研究人视网膜色素上皮 (RPE)细胞对吲哚青绿 (ICG)的摄取和代谢规律以及 ICG在细胞内的亚细胞定位。 方法 将 RPE细胞与 0 .2 5 mg/ ml ICG在 37℃暗箱中共同孵育 1、4、2 4 h后 ,应用透射电子显微镜观察细胞浆内 ICG颗粒和细胞超微结构改变。荧光显微镜下观察 RPE细胞与 ICG共同孵育 1、2、4、8、12、2 4、4 8h后细胞浆内 ICG的自发荧光。应用紫外 /可见光分光光度计测定梯度稀释的ICG溶液 80 5 nm吸光度 [A,旧称光密度 (OD) ]值 ,绘制 ICG溶液浓度的标准曲线 ,计算 ICG浓度与 A值的相关公式。RPE细胞与 ICG共同孵育 1、2、4、8、12、2 4、4 8、72 h后检测上清液 80 5 nm A值 ,代入公式 ,计算细胞对 ICG的吸收情况。RPE细胞与 ICG共同孵育 2 4 h后 ,1周内每次取 1个样本进行透射电子显微镜和荧光显微镜检查 ,记录 RPE细胞对 ICG的代谢周期。 结果 ICG进入细胞后 ,在细胞浆内均匀分布。 0 .2 5 mg/ ml ICG作用 RPE细胞 2 4 h后 ,对细胞超微结构无显著影响。RPE对 ICG的吸收随孵育时间延长逐渐增加。共同孵育 2 4 h后 ,RPE细胞对 ICG的摄取达高峰 ,以后由于细胞对其缓慢代谢而逐渐下降。 1周后 RPE细胞内仍有微量 ICG残留。 结论 RPE细胞通过主动转运摄取 ICG。ICG在

Objective To investigate the ingestion, metabolism and subcellular localization of indocyanine green (ICG) in human retinal epithelial (RPE) cells. Methods RPE cells were incubated with 0.25 mg/ml ICG under the condition of 37℃ in the camera. The ICG granule and ultrastructure of RPE cells were observed under the electron microscopy after 1-, 4-, and 24-hour incubation, and the ICG autofluorescence was detected by fluorescence microscopy after the incubation for 1, 2, 4, 8, 12, 24, and 48 hours, respectively. The absorbency (A value) of ICG solution was measured at 805 nm with ultraviolet/visible specrtrometer. The standard curve of concentration of ICG was drawn and the related equation of concentration of ICG and the A value was calculated. After being incubated for 1, 2, 4, 8, 12, 24, 48, and 72 hours, respectively, the A value of supernatant fluid was calculated according to the equation. After incubated with ICG for 24 hours, one sample was observed under electron microscope and fluorescence microscope per week to evaluate the metabolizable period of ICG. Results ICG granules were distributed evenly after entering the RPE cells. After incubated with 0.25 mg/ml ICG for 24 hours, no significant change of the ultrastructure of the RPE cells was found. ICG granules accumulated in the cells as the time goes by and reached the peak after 24 hours, and then they decreased because of the slowdown of the metabolism. Few ICG was still remained in the cells 1 week later. Conclusions RPE cells may take in ICG actively. ICG metabolizable period in RPE cells is long, which may be one of the mechanisms of the toxicity of ICG to the retina in the vitreous operation.