Constant low LED light exposure effects in retinal neurons.

cordoba

Encuentro; IX Encuentro de Jóvenes Investigadores en Neurociencias de Córdoba; 2017

The retina is a complex neural circuit that transduces light into a pattern of electrical impulses to the brain. This tissue fulfills a visual role through rods and cones and the synchronization of circadian rhythms through ganglion cells (GC), specifically through a subpopulation of photosensitive GC (ipRCGs). The process of retinal degeneration (RD) by low intensity LED light stress is not well characterized. Previously, we demonstrated rods and cones death and a reduced functionality of these cells after 4 days of light exposure. So, our goal was to evaluate the constant low LED light stimuli effects over visual photoreceptors and ipRCGs, studding the oxidative stress mechanism, Rhodopsin (Rho), Melanopsin (Opn4) and Neuropsin (Opn5) expression and Rho phosphorylation. Male Albino Wistar rats were exposed to white LED light (200 lx) for 1 to 8 days. We found a significant increase in retinal reactive oxygen species production after 5 days of light; the enzymatic activity of catalase was not different between groups. The number of GCs was not altered by light exposure. The expression of Opn4 increased and its location varied from neuritas to somas along the days. Opn5 was localized in GCs and inner nuclear layer with higher expression levels after 6 days. Also, we found that Rho phosphorylation was reversible if the animals were exposed to 48 hours of darkness after light treatment. All this results suggest that exists RD with a re-structuration in photoreceptor cells in low light exposure stress.