Abstract
Purpose :
Light induced models of retinal degeneration are used to recapitulate the retinal pathology of age-related macular degeneration (AMD) and have generally been successful in non-pigmented animals. Current light-induced damage models of AMD are preformed using a prolonged dark adaptation period of seven to fourteen days followed by several days of exposure to high intensity light. The purpose of this study was to see if retinal damage would occur in pigmented zebrafish using a short period of dark adaptation followed by 48 hours of exposure to high intensity light. .
Methods :
Pigmented wild type zebrafish were dark adapted for 24 hours and then exposed to two 8000 lumen LED lights, which were each placed 30 cm away from the tank. Reflective material was placed behind tank to divert light lost due to scattering thus increasing efficiency of light exposure. Fish were collected at 0 hours and 48 hours post dark adaptation. A subset of fish were allowed to recuperate for 28 days before they were collected. Immunohistochemistry analysis using confocal microscopy was performed on vertical retinal sections in order to visualize cones, rods, and the outer nuclear layer of the retina, so that retinal damage could be assessed.
Results :
The photoreceptors in the retinas of zebrafish collected at 48 hours post dark adaptation showed evidence of damage after exposure to continuous light in comparison to the retinas of zebrafish collected at 0 hours post dark adaptation. Zpr-1 labeled cones and rhodopsin labeled outer segments in rods were severely truncated after light irradiation. However, photoreceptors from zebrafish that were allowed to recuperate for 28 days, still showed some signs of damage.
Conclusions :
Retinal damage in pigmented zebrafish will still occur after light irradiation with short periods of dark adaptation. The short duration dark adaptation prior to high intensity illumination provides a significant advantage of time. This approach avoids issues related to feeding and intermittent light exposure, which may require special housing in a darkroom or a light tight dark box. Taken together, this modified model may be used as an alternative to light induced models of AMD with extended periods of dark adaptation, and save valuable time and effort.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.