The effect of severe zinc deficiency on the morphology of the rat retinal pigment epithelium.

Male Sprague-Dawley weanling rats maintained on a controlled dietary zinc intake had an accumulation of osmiophilic inclusion bodies in the retinal pigment epithelium (RPE) of the zinc-deficient group. At 7 weeks of zinc deficiency there were marked ultrastructural alterations of the RPE. In some instances a deepening of the basal infoldings of the cells of the RPE were observed. There was also vesiculation and degeneration of the photoreceptor outer segments. No changes were observed in the pair-fed, weight-restricted, and ad libitum-fed controls. The possible functions of zinc in the retina are discussed.