Retinal degeneration promoted by excessive light: Role of the Glial cells.

MANUEL BRUERA; MERCEDES BENEDETTO; ALICIA DEGANO; MARIA ANA CONTIN

Villa Carlos Paz, Cordoba

Congreso; XXXIV Reunión Anual SAN 2019; 2019

Sociedad Argentina de Neurociencias

Excessive exposure to artificial light affects the retina inducing photorec eptors cell death and leading to retinal degeneration (RD). Previously, we have established a novel model of RD by exposing adult rats to constant lo w intensity LED lights (200lux). Using this model w e showed tha t, after 5 days of exposure, the retina suffers important structural changes including photoreceptors cell death, opsins re localization and increased oxidative stress.In the present work,we aimed to understand the role of neuroinflammation in theRD pr omoted by light excess; thus, we assessed the time course of glia activation after 2, 4, 6 and 8 days of constant light exposure. Retinas were processed either for western blotting (WB) or I HC and we evaluated GFAP expression (Müller cells)and Iba 1 expre ssion (microglia marker).After 4 days of exposure, we observed a significant increase of active microglial cells (ameboid shaped) and also, the active microglia relocated towards the outer retina (next to rods and cones nuclei). At the same time point, we observed strong Müller cells activat ion compared to controls. Interestingly, WB analysis of the same retina revealed the appearance of breakdown GFAP products (GFAP BDPs), a proposed bi omarker for Central Nervous System injury at two days ex posure.Thus , our results indicate that glial activation precedes the photoreceptors cell death and suggest that an inflammatory response may be inducing cell deathpathways in our RD model.