ZnPcS_4-光动力疗法对人视网膜色素上皮细胞的作用

Photodynamic Effects of ZnPcS_4 on Human Retinal Pigment Epithelium Cell

目的探讨四磺酸酞菁锌(ZnPcS4)介导的光动力疗法(PDT)对人视网膜色素上皮细胞的作用。方法从意外死亡者眼球中分离出视网膜色素上皮(RPE)细胞,用紫外可见光谱分析仪观察RPE细胞对ZnPcS4的摄取及代谢的规律,确定PDT的最佳时间点,根据激光能量密度分为50和100 J/cm2组。用MTT计算RPE细胞的抑制率。PDT后1h,用荧光显微镜及流式细胞仪观察和检测细胞内活性氧的含量。结果光照对RPE细胞的抑制率随激光能量密度增强而增强。ZnPcS4介导的PDT作用后,RPE细胞内活性氧含量PDT组与对照组比较,差异有非常显著意义。结论 RPE细胞对ZnPcS4的吸收4 h达到高峰。ZnPcS4介导的PDT作用后,RPE细胞内活性氧含量显著增加,对细胞有一定的损伤作用。

Objective To investigate the effects of phototoxicity on human retinal pigment epithelial （RPE） cells after zinc tetra - sulfonated phthalocyanine （ZnPcS4 ） based photodynamic therapy （PDT）. Methods The 2-4 generations of subcultured RPE cells were used in the study. Firstly, the cellular uptake of ZnPcS4 was quantified by UV-spectra after confluent RPE cells were exposed to various doses of ZnPcS4 for 1-6 hrs. Secondly, RPE cells were divided into four groups ： the control group, the group of photosensitizer without irradiation, the PDT 1 group （ irradiated with 50 J/cm2 ） and PDT 2 group （irradiated with 100 J/cm2）that were exposed to 10mg/ml ZnPcS4 before irradiation. After PDT, cell viability was evaluated by MTI＇, and reactive oxygen species （ROS） was assessed by flow cytometry and confocal microscopy. Results It was also found that four hours after incubation were the optimal time point to irradiate the cells. The cellular viability re- duction ratio of RPE cells in the PDT 1 and PDT 2 groups after ZnPcS4 based PDT was significantly higher. PDT results in a significantincrease in ROS. Conclusions Intracellular ROS formation may play an important role in the mediating apoptotic processes of RPE cells induced by Zn- PcS4 based PDT. It is an important precondition that in order to decrease damage on RPE we should avoid irradiating RPE cells at this period.