Abstract
Abstract: :
Purpose: To investigate the changes of cornea due to vitamin E deficiency and determine the effects of vitamin A supplementation. Methods: Male infant rats from normal mothers were weaned at 20 days of age and divided into two groups: Group 1, E(-), rats were fed a vitamin E-deficient diet; Group 2, E(-)A(+), rats were fed a vitamin E-deficient diet and injected intraperitoneally with 5000IU of vitamin E per 2 week. At 16 months of age, the corneal changes of these rats were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results: The body weight between the two groups showed no significant difference (P=0.0686, t-test comparison of means). The serum vitamin A level was significantly higher in the E(-)A(+) rats than that in the E(-) rats (P=0.0320, t-test comparison of means). SEM showed more fine microvilli and clear cells in the most superficial epithelial layer of the cornea in the A(-)E(+) rats than in the E(-) rats. The surface of the cornea in the E(-)A(+) rats was smooth. But, the surface of the cornea in the E(-) rats was slightly rough and uneven. Some exfoliating cells were seen in the cornea of the E(-) rats. TEM showed abnormal structures in the E(-) rats. There are some high electron dense deposits in the subepithelial layer of the stroma in the E(-) rats. The number of hemi-desmosomes in the E(-) rats was decreased. On the other hand, the epithelium in the E(-)A(+) rats looked normal. There were many light cells with numerous microvilli in the most superficial layer and many hemi-desmosomes at the basal cells in the E(-)A(+) rats. Conclusions: The present study suggests that the cornea is obviously damaged by vitamin E-deficiency and that vitamin A has a protective effect against the corneal damages caused by vitamin E-deficiency.
Keywords: cornea: epithelium • microscopy: electron microscopy • cornea: basic science