VITAMIN-E-DEFICIENCY AND THE RETINA - PHOTORECEPTOR AND PIGMENT EPITHELIAL CHANGES

Abstract

To investigate the role of normal vitamin E levels and the interrelationships between vitamins E and A in maintaining the visual cells of the weanling female Sprague-Dawley rats were fed vitamin E-free diets differing 10-fold in their vitamin A content (08 and 8.0 mg pf retinol per kg of diet). Rats on vitamin E-free diets with the higher vitamn A level exhibited marked disruption of photoreceptor outer segment membranes and a 5-fold increase in the number of lipofuscin granules in the pigment epithelial cells which ingest these membranes. Rats on vitamin E-free diets with the lower vitamin A level showed the same retinal damages plus significant loss of photoreceptor cells compared to age-matched rats on control diets. Rods and cones were involved equally, and their pattern of loss was not like that found in vitamin A deficiency. Normal levels of vitamin E probably protect photoreceptor membranes from oxidative damage and retard the accumulation of their remnants and other products of lipid breakdown in the pigment epithelium. The vitamin A status of rats has a significant influence on the extent of damage induced by vitamin E deficiency.