Low Led Light Exposure as a Model of Retinal Degeneration in Albino Rats

Córdoba

Congreso; XXXIII Congreso Anual de la Sociedad Argentina de Investigación en Neurociencias; 2018

Excessive exposure to artificial light (light pollution [LP]) can accelerate the course of certain genetic diseases, induce the death of rod cells, and promote circadian asynchrony, triggering the development of retinal degeneration (RD).Previously we developed an RD model by constant exposure of albino rats to low-intensity LED light (LL). This model is characterized by the death of rods, an increase in rhodopsin (Rho) phosphorylation and changes in the expression andlocalization of Opn4 and 5 in the internal retina. Based on this background, we decided to study the kinetic of rod cells death, so, we evaluated the levels of oxidative stress (OS), the composition of fatty acids in membranes, ERG responses, and whether Rho phosphorylation is a reversible mechanism. Our results show that the treatment with light produces a significant increase of OS levels after 4 days of LL. The changes in OS metabolites are followed by a significant reduction of docosahexaenoic acid, indicating the oxidation of membrane outer segment. Nevertheless, ERGs showed retinal activity completely abolished after LL3, suggesting an interruption of rods activity before OS. Finally, Rho phosphorylation was reversible if the animals were exposed to darkness for 48 hr after LL treatment. These results give evidence of a possible role of OS in the development of RD and the putative role of Rho phosphorylation/ dephosphorylation. This model of constant light exposuremay provide knowledge of LP effects.