Abstract
Purpose :
Age-related macular degeneration (AMD) is a major cause of blindness in the elderly population. It is characterized by the loss of central vision due to damaged retinal pigment epithelium (RPE) cells and photoreceptors. Blue Light (BL) exposure was proposed as a risk factor for AMD progression as it triggers RPE cell loss. We undertook this study to determine the effects of BL on the behaviour of RPE cells and their potential mitigation by BL-filtering intraocular lenses (IOL).
Methods :
A2E-loaded ARPE-19 cells and human eye-isolated primary RPE cells were exposed or not to BL (400 – 500 nm) under a Solar Simulator (TSS-156R, OAI) set at 100 mW/cm2, in the absence or presence of either clear ultraviolet (UV)-filtering intraocular lenses (CIOL), or a yellow UV- and BL-filtering IOL (YIOL). RPE cells were analyzed for (i) their oxidative stress by measuring both total cellular and mitochondrial reactive oxygen species (ROS), and (ii) their viability. The involvement of ROS in the cytotoxic effects of BL was investigated following the pre-treatment of RPE cells with the antioxidant N-acetyl cysteine (NAC). 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 RPE cells exposure to BL significantly increased the levels of both total cellular ROS (P < 0.001) and mitochondrial superoxide anion (P < 0.001). While these increases were not affected by placing the CIOL in the BL beam, YIOL decreased the levels of both ROS reservoirs (P < 0.01; compared to BL-exposed cells). Increased ROS production induced following BL exposure was accompanied by a significant increase in cell death (P < 0.001). Similarly, in contrast to CIOL, YIOL reversed the effects of BL on RPE cell viability (P < 0.001). Notably, pre-treatment of cells with NAC abolished the increased cell death, suggesting that the cytotoxic effects of BL on RPE cell were mainly due to increased levels of ROS.
Conclusions :
Our data indicate that BL is cytotoxic to RPE cells due to increased oxidative stress. These effects were mitigated by filtering these radiations. The use of BL-filtering devices may represent a strategy to reduce the BL harmful effects on RPE cells and delay the onset of AMD.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.