Retinal light damage: Protective effect of α-tocopherol

Abstract

We studied histologically the protective effect of α-tocopherol to retinal light damage. After 3-week-old albino rats were fed with an α-tocopherol deficient or supplemented diet and kept in a 12-hour dim light/12-hour dark environment for 8 weeks, each animal was exposed to intense light (2500 lux) for 1, 3, 6, 12, 24, and 72 hours. The eyes were enucleated and prepared for transmission electron microscopy study and image analysis of phagosomes. Before light exposure, the α-tocopherol content of the neural retina of the deficient and supplemented groups was 0.3 μg and 23.34 μg, respectively. After 1- and 3-hour exposures, morphological changes in the retinal pigment epithelium and photoreceptor membranes were more extensive in the deficient group than in the supplemented group. After a 24-hour exposure, pyknotic photoreceptor nuclei were more numerous in the deficient group than the supplemented group. After 3-, 6-, and 12-hour exposures, large phagosomes were more numerous in the deficient group than in the supplemented group. These findings suggest that α-tocopherol can protect the retina from light injury for up to 24 hours of exposure.