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

BRUERA, MANUEL GASTÓN; BENEDETTO, MARÍA MERCEDES; DEGANO, ALICIA LAURA; CONTIN MARIA ANA

CÓRODBA

Congreso; XXIV Congreso Anual de la Sociedad Argentina de Investigación en Neurociencias; 2019

Sociedad Argentina de Investigación en Neurociencias (SAN)

Excessive exposure to artificial light affects the retina inducing photoreceptors cell death and leading to retinal degeneration (RD). Previously, we have established a novel model of RD by exposing adult rats to constant low intensity LED lights (200 lux). Using this model we showed that, 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 the RD promoted 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 IHC and we evaluated GFAP expression (Müller cells) and Iba-1 expression (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 activation compared to controls. Interestingly, WB analysis of the same retina revealed the appearance of breakdown GFAP products (GFAP-BDPs), a proposed biomarker for CNS injury at two days? exposure. Thus, our results indicate that glial activation precedes the photoreceptors cell death and suggest that an inflammatory response may be inducing cell-death pathways in our RD model.