Effects of Light‐emitting Diode Radiations on Human Retinal Pigment Epithelial Cells In Vitro

Abstract

Human visual system is exposed to high levels of natural and artificial lights of different spectra and intensities along lifetime. Light-emitting diodes (LEDs) are the basic lighting components in screens of PCs, phones and TV sets; hence it is so important to know the implications of LED radiations on the human visual system. The aim of this study was to investigate the effect of LEDs radiations on human retinal pigment epithelial cells (HRPEpiC). They were exposed to three light-darkness (12 h/12 h) cycles, using blue-468 nm, green-525 nm, red-616 nm and white light. Cellular viability of HRPEpiC was evaluated by labeling all nuclei with DAPI; Production of reactive oxygen species (ROS) was determined by H2DCFDA staining; mitochondrial membrane potential was quantified by TMRM staining; DNA damage was determined by H2AX histone activation, and apoptosis was evaluated by caspases-3,-7 activation. It is shown that LED radiations decrease 75-99% cellular viability, and increase 66-89% cellular apoptosis. They also increase ROS production and DNA damage. Fluorescence intensity of apoptosis was 3.7% in nonirradiated cells and 88.8%, 86.1%, 83.9% and 65.5% in cells exposed to white, blue, green or red light, respectively. This study indicates three light-darkness (12 h/12 h) cycles of exposure to LED lighting affect in vitro HRPEpiC.

Effect of monochromatic visible light on intracellular superoxide anion production and mitochondrial membrane potential of B16F1 and B16F10 murine melanoma cells

“…These results suggest that blue light enhances intracellular ROS production on both B16F1 and B16F10 melanoma cells. Chamorro et al () also reported that blue light increase ROS level on human retinal pigment epithelial cells. Superoxide can trigger the chain of reaction to apoptosis (Jancar et al, ).…”

Effects of white light‐emitting diode (LED) light exposure with different Correlated Color Temperatures (CCTs) on human lens epithelial cells in culture

“…Chamorro et al . analyzed human RPE cells irradiated with monochromatic blue (468 nm), green (525 nm), and red (616 nm) LED light, and multichromatic white LED light (CCT not clarified) (5 mW cm −2 ). Significant DNA damage and apoptosis was present in cells treated with blue and white light.…”

“…Chamorro et al . also demonstrated that more DNA damage and apoptosis of retinal pigment epithelial (RPE) cells were caused by blue LED light than green and red.…”

“…Previous studies have demonstrated that blue light (400-500 nm) induced oxidative stress and cellular damage in retinal tissues (2)(3)(4)(5)(6). Chamorro et al (7) also demonstrated that more DNA damage and apoptosis of retinal pigment epithelial (RPE) cells were caused by blue LED light than green and red.…”

LED light between Nobel Prize and cancer risk factor

“…Blue LED illumination, which emits light at the short end of the visual spectrum (440-480 nm), has been demonstrated to be the most effective frequency for melatonin suppression compared with conventional lighting technologies (Falchi et al, 2011;West et al, 2011). Finally, looking directly to the source of LED illumination can severely damage retinal cells (Chamorro et al, 2013).…”