Retinal Neurocytes are more Sensitive to Blue Light-induced Damage than Gliocytes Due to DNA Double-strand Breaks

Abstract

Purpose : Blue light is a major component of visible light and LED digital displays. Here, we sought to investigate DNA stability and its mechanism in retinal neurocytes and gliocytes following blue light-induced injury.

Methods : The effects of blue light exposure on retinal cells were assayed both in vitro and in vivo. Cell viability and cell apoptosis assays monitored light-induced lesion. DNA double strand breaks (DSBs) were tracked by γ-H2AX. Additionally, the level of mRNAs and proteins associated with DNA repair was measured by real time RT-PCR and western blot, respectively. An adult rat model was used to assay the effect of blue light stimulation on retina in vivo.

Results : Short-term, blue light exposure impairs cell viability and induces cell apoptosis in retinal neurocytes, in an illuminance-dependent manner, in vitro. DNA ladder formation and a significant increase of γ-H2AX foci indicate severe DNA DSBs in retinal neurocytes after short-term blue light exposure. Moreover, more DNA DSBs occur in retinal neurocytes other than that in gliocytes upon blue light treatment, which might relate to the higher Ku80 expression, an important DNA repair protein. Furthermore, following short-term blue light exposure, DNA DSBs are shown in ganglion cell lay in vivo, and only observed in Map2-positive cells. Additionally, a month-long cycle of blue light exposure significantly thinned the retina, compared to controls.

Conclusions : Our findings demonstrate that over exposure of blue light induces DNA DBSs in retinal neurocytes, and the damage is more pronounced, compared to gliocytes, suggesting a cell-specific component to blue-light-exposure injuries.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.