Effect of high-intensity light on the retinal pigment epithelium of zebrafish - An induced retinal damage study model

Abstract

Background: Natural light sources emit light with two physical properties namely, spectrum and intensity. However, the electronic light sources these days were adjusted in their parameters of color and the intensity without the consumer being aware of these. These lights become potential harm to its users both in household and handheld digital devices. Aims and Objectives: In this study, we have tried to estimate the changes in the morphology of the retinal pigment epithelium of zebrafish when exposed to high-intensity light. Materials and Methods: Institutional Animal Ethics Committee clearance was obtained. Two groups of zebrafish with an average bodyweight (690 ± 50 mg) and length (26.75 ± 1.39 mm) were taken for the study. Group I (n = 6) control group: Housing was in a glass tank in the common working area exposed to the sunlight for the light source. Group II (n = 6) study group: Housing was done in a dark room with the custom-built electrical light source with an adjustable setting for a uniform light intensity of 15,000 lux. Experimental study period was for 15 days with maintained 12 hrs light and 12 hrs dark cycle. Fishes were euthanized by exposing them to cold water with ice and the eyeballs removed and stored in 4% formalin. Whole eye histological staining was done with hematoxylin and eosin stain. The histological slides were photographed in a digital microscope and the distribution of neurons in the selected layer of the retinal epithelium was estimated and compared among the groups using a software. Results: The study results are conclusive with zebrafish animal models and further suggest that even under the water when exposed to high intensity of light there is a potential risk of damaging the retinal epithelium. Conclusion: An experimental damage of the retinal epithelium of zebrafish was established to be used for further research.