Abstract
Purpose: :
To investigate the cause of the arciform area of heightened light sensitivity in the pigmented rat retina.
Methods: :
In Lister–Hooded and pigmented non–dystrophic RCS rats, the areas of the left retina exposed to light were modified using various surgical procedures, such as advancing the conjunctiva over the cornea or rotating the eye. Immediately after, the left pupil was dilated with atropine and the animals were exposed to light (3000 luxes) continuously for 72 hours. Animals were processed between 0 hours and 3 months after light exposure. Before processing, the eye fundus was inspected and in some animals, type I horseradish peroxidase (HRP) or fluorescein isothiocyanate dextran (FID) were injected into the femoral vein to label the retinal vessels. Retinas were dissected as whole mounts or processed for cross–sections, reacted for HRP demonstration or incubated with different antibodies (RT97, GFAP, RECA).
Results: :
The dimensions and/or location of the sensitive arciform retinal area varied depending on the surgical procedures: Eye rotation induced a displacement of the arciform area and conjunctival advancement over the cornea protected the corresponding part of the retina from light injury.
Conclusions: :
The arciform area of heightened light sensitivity in the rat retina is due to increased light exposure of this area, which may be due to light entering the eye though the interpalpebral fissure.
Keywords: photoreceptors • radiation damage: light/UV • retinal degenerations: cell biology