Interaction of zinc and vitamin A on the ocular surface
- Cite this article as:
- Kanazawa, S., Kitaoka, T., Ueda, Y. et al. Graefe's Arch Clin Exp Ophthalmol (2002) 240: 1011. doi:10.1007/s00417-002-0586-4
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Purpose. The purpose of this study was to assess morphologically the interaction between zinc and vitamin A in their effect on the ocular surface.
Methods. Three-week-old Wistar Kyoto rats were divided into five groups: group A(+) Zn(+) was fed a diet containing both vitamin A and Zn; group A(–) was fed a vitamin A-deficient diet; group A(–) Zn(+) was given a vitamin A-deficient diet and deionized distilled water with Zn; group Zn(–) and group Zn(–) A(+) were fed a Zn-deficient diet, whereby group Zn(–) A(+) received an intraperitoneal injection of vitamin A. Corneas and conjunctivas of each group were examined by electron microscopy.
Results. The corneas and conjunctivas of group A(–) demonstrated a decrease in the number of microvilli in the epithelium. The corneas and conjunctivas of group A(–) Zn(+) had a decrease in microvilli but more microvilli than those of group A(–). The corneas of group A(–) showed keratinization, but those of group A(–) Zn(+) showed no keratinization. In group Zn(–) the microvilli on the conjunctiva and cornea were sparse. Group Zn(–) A(+) had a decrease in microvilli but more microvilli than group Zn(–). The conjunctivas of group Zn(–) A(+) had more goblet cells with granules than did those of group Zn(–).
Conclusion. These results suggest that a synergistic interaction exists between vitamin A and zinc for the maintenance of the corneal and conjunctival epithelium.