Vitamin E prevents changes in the cornea and conjunctiva due to vitamin A deficiency

Abstract

Purpose: To determine whether vitamin E can prevent changes in the cornea and conjunctiva due to vitamin A deficiency.

Methods: Male infant rats from normal mothers were weaned at 20 days of age and divided into three groups: in group 1, A(-), rats were fed a vitamin A-deficient diet; in group 2, A(-)E(+), rats were fed a vitamin A-deficient diet and injected intraperitoneally with 15 mg of vitamin E per week; group 3 rats were normal controls. At 13 weeks of age, the corneal and conjunctival changes were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Results: SEM showed more fine microvilli and clear cells in the most superficial epithelial layer of the cornea and conjunctiva in A(-)E(+) rats than in that of A(-) rats. Numerous secretory granules were seen in the goblet cells of the conjunctiva of A(-)E(+) rats, but in A(-) rats there was a total absence of conjunctival goblet cells. TEM showed a severely keratinized corneal surface in A(-) rats. On the other hand, the corneas of A(-)E(+) rats were almost normal in appearance. The conjunctivae of A(-) rats had superficial epithelial keratinization, scarce goblet cells, and many keratohyalin granules in the epithelium and dark cells, while in the conjunctivae of A(-)E(+) rats there were numerous secretory granules in goblet cells and some dark cells.

Conclusion: The present study suggests that vitamin E has a protective effect against the corneal and conjunctival damage caused by vitamin A deficiency.