Effects of Spectrum of Wavelengths of Blue-Light on Retinal Pigment Epithelial Cells

Abstract

Purpose : Age-related macular degeneration (AMD) is a major cause of blindness in the elderly population. It is characterized by loss of central vision due to damaged retinal pigment epithelium (RPE) cells and photoreceptors. Blue Light (BL) is recognized as a risk factor for AMD as it triggers RPE cell death. As BL covers a large light spectrum, we undertook this study to determine the exact range of BL wavelengths that affect the behaviour of RPE cells.

Methods : RPE cells (ARPE-19 and h-TERT-RPE1 cells) were exposed or not to BL (400 – 500 nm) under a Solar Simulator (TSS-156R, OAI) set at 50 mW/cm². RPE cells were analyzed for (i) their growth (using the Incucyte live imaging system to assess cell confluence, and the CCK8 assay to assess cell metabolic activity), and (ii) their oxidative stress by measuring mitochondrial reactive oxygen species (mROS) (using the MitoSox probe). All experiments were performed at least 3 times, and data were compared using an ANOVA followed by the Dunnett post-hoc test for multiple comparisons with one control group. A p value < 0.05 was considered statistically significant.

Results : We observed that BL exposure significantly decreased the proliferation of RPE cells (58 +/- 4% decrease in cell confluence), and their metabolic activity (51 +/- 5% reduction). To get an insight on the mechanisms underlying the observed effects, we analysed the effects of BL on oxidative stress. We noted that although non-exposed RPE cells displayed a baseline level of mROS, BL significantly increased the amount of mROS production (3 times increase). Using a set of filter cut-offs, we noticed that BL at wavelengths above 460 nm did not affect RPE cell behavior. In contrast, BL at wavelengths ranging from 400 to 460 nm was responsible for the deleterious effects observed on exposed RPE cells.

Conclusions : Our data show that BL at wavelengths below 460 nm are deleterious to RPE cells due increased oxidative stress. The use of lenses with a filtering potential below 460 nm may reduce the harmful effects of these radiations on RPE cells and delay the onset of AMD.

This is a 2021 ARVO Annual Meeting abstract.