Study on visual and non-visual opsins in a model of retinal degeneration caused by LED lights.

BENEDETTO, MARÍA MERCEDES; QUINTEROS QUINTANA, MARIA LUZ; GUIDO MARIO EDUARDO; CONTIN MARIA ANA

Congreso; Sociedad Argentina de Bioquímica y Biol. mol (SAIB); 2016

SAIB

Study on visual and non-visual opsins in a model of retinal degeneration caused by LED lights.The retina is a complex neural circuit that transduces light into a pattern of electrical impulses to the brain. This tissue fulfils a visual role through rods and cones and the synchronization of circadian rhythms by a subpopulation of photosensitive ganglion cells (GC). The process of retinal degeneration (RD) by low intensity LED light exposure is not well characterized. Previously, we demonstrated rods and cones death and a reduced functionality of these cells after 4 days of light exposure. In this work, our goal was to evaluate the constant low LED light stimuli effects over visual photoreceptors and GC, studying 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 GC was not altered, however, the expression of Opn4 increased and its location varied from neuritas to somas along the days. Opn5 was localized in GC and inner nuclear layer with higher expression levels after 8 days. Also, we found that Rho phosphorylation was reversible if animals were exposed to 48 hrs of darkness after light treatment. All this results suggest the occurrence of RD with a re-structuration in photoreceptor cells in low light exposure stress.