The effects of zinc deficiency on developing photoreceptors in the rat retina: a scanning microscopic study.

A study was undertaken to observe the effects of dietary zinc deficiency on the topographical morphology of developing photoreceptor (rod) cells in the sensory retina of the rat. Observations were made by means of scanning electron microscopy (SEM). Pups were utilized from three groups including (1) zinc deficient (2) pair-fed controls and (3) ad libitum controls. Animals ranged in age from birth to twenty days. Femur zinc levels were measured by flame atomic absorption spectrophotometry. A statistically significant increase in the number of photoreceptor cells continued through the 6th day, however, no morphological differences were noted among cells during the first 13 days. By day 14, outer segments appeared more elongated in ad libitum control tissues. No differences in outer segment length were apparent by day 20.