AIM:To study the effect of vitamin E on the injury of human retinal pigment epithelial(hRPE)cells induced by high-dose blue light, and provide experimental evidence for intercepting blue light damaged hRPE cells.

METHODS: The hRPE cell injury model was established with 3000±150Lx blue light. The apoptosis rate and reactive oxygen species(ROS)of the six groups of hRPE cells were detected by flow cytometry at 0, 3, 6, 9, 12 and 24h respectively. Apoptosis and ROS in hRPE cells were detected by cytometry in 0h-irradiation group, 6h-irradiation group, and vitamin E added groups(vitamin E concentration 10, 50, 100μmol/L)before or after 6h-irradiation. The fluorescence intensity of hRPE cells was observed under a fluorescence microscope using Hoechst 33258 staining reagent.

RESULTS: Compared with the 0h-irradiation group, the relative amount of reactive oxygen species increased significantly in 3, 6, 9, 12 and 24h groups(all P<0.01), the apoptosis rate of hRPE cells increased significantly in 6, 9, 12 and 24h groups(all P<0.01), the apoptosis rate of the 3h-irradiation group was not statistically significantly increased(P=0.46). Compared with the 6h-irradiation group, the relative amounts of ROS and apoptotic rate of the six groups of hRPE cells added vitamin E were significantly decreased, and the blue fluorescence of Hoechst 33258 released in the cells gradually decreased, which was concentration dependent(all P<0.01),except for apoptosis rate of hRPE cells in the 10 μmol/L vitamin E group before irradiation(P=0.66). Compared with the 0h-irradiation group, the difference in the relative amount of ROS and apoptosis rate of hRPE cells in added groups were statistically significant(all P<0.01). At the same concentration of vitamin E, the relative amount of ROS and apoptosis rate of hRPE cells added vitamin E after irradiation were significantly lower than those added vitamin E before irradiation(all P<0.01), except for apoptosis rate of hRPE cells in the 10 μmol/L vitamin E group, which had no difference between added before and after irradiation(P=0.08).

CONCLUSION: After hRPE cells had been irradiated by blue light, the increase in the relative amount of intracellular ROS was earlier than that of apoptosis. Elimination of intracellular ROS is the idea of intercepting high doses of blue light induced hRPE cell injury. Vitamin E protects RPE cell against damage induced by high doses of blue light, and the effect becomes stronger as the concentration of vitamin E increases, which is better when added after irradiating. However, it doesn't take effect until the concentration reaches a certain level. And the damage can't be completely repaired.