Light-Induced Retinal Degeneration in the Albino Mice Retina

Abstract

Purpose: : To investigate light-induced retinal degeneration in albino mice and to determine whether they also show also an arciform area of heightened light sensitivity, as we have shown before in rats (Marco-Gomariz et al., J. Comp. Neurol. 498(2006):163-179, García-Ayuso et al., Invest. Ophthalmol. Vis. Sci. 49(2008) :E-Abstract 4395).

Methods: : BALB/c albino mice were dark adapted overnight, the left pupil dilated with topical atropine and exposed to light (3000 lux) for 24 hours, starting between 10 and 12 a.m. Three days before, and 7, 14 and 30 days after light exposure, an electro-retinogram (ERG) was recorded from both eyes. The animals were processed immediately or 7, 14, 30 or 90 days after light exposure and the retinas were dissected as whole mounts or cross-sectioned. Horseradish peroxidase was injected intravenously to label retinal vessels, the TUNEL technique was used to document apoptosis and retinal cross sections were stained with hematoxylin-eosin or incubated with different antibodies in order to label retinal neurons.

Results: : Photoreceptor cell death by apoptosis was observed immediately after light exposure and continued throughout the period of study in both eyes. The amount of cell death was similar in both eyes and was more marked in the central than in the peripheral retina. The amplitudes of both the a and b waves of the ERG were significantly decreased after light exposure. This decrease was more marked for the a wave; the implicit time was not affected.

Conclusions: : Light exposure causes photoreceptor cell death by apoptosis in BALB/c mice and, consequently, a decreased functionality of the retinal neurons that can detected by electroretinography.

Keywords: radiation damage: light/UV • retinal degenerations: cell biology • photoreceptors