Stress granule induction in rat retinas damaged by constant LED light

Abstract

Objectives Stress granules (SGs) are cytoplasmic biocondensates formed in response to various cellular stressors, contributing to cell survival. While implicated in diverse pathologies, their role in retinal degeneration (RD) remain unclear. We aimed to investigate SG formation in the retina and its induction by excessive LED light in a RD model. Methods Rat retinas were immunohistochemically analyzed for SG markers G3BP1 and eIF3, and SGs were also visualized by RNA FISH. Additionally, SGs were induced in primary retinal cell and eyeball cultures using sodium arsenite. Light exposure experiments utilized LED lamps with a color temperature of 5,500 K and 200 lux intensity for short-term or 2-8-day exposures. Results SGs were predominantly detected in retinal ganglion cells (RGCs) and inner nuclear layer (INL) cells, confirmed by sodium arsenite induction. SG abundance was higher in animals exposed to light for 2-8 days compared to light/dark cycle controls. RGCs consistently exhibited more SGs than INL cells, and INL cells more than outer nuclear layer cells (Scheirer-Ray-Hare test: H 13.2, p = 0.0103 for light condition, and H 278.2, p < 0.00001 for retinal layer). These observations were consistent across four independent experiments, each with three animals per light condition. Conclusions This study identifies SGs in the mammalian retina for the first time, with increased prevalence following excessive LED light exposure. RGCs and INL cells showed heightened SG formation, suggesting a potential protective mechanism against photodamage. Further investigations are warranted to elucidate SGs’ role in shielding against light stress and their implications in retinopathies.