Effects of three kinds of topical eye-drops on the experimental rabbit dry eye.

We studied the ultrastructural changes of the corneal epithelium of the experimental rabbit dry eye and the effects of three topically applied eye-drops. Fourty rabbits were divided into experimental rabbit dry eye group, 0.1% bromhexine-treated group, 50% Chinese medicinal herb-treated group and 0.01% retinoic acid-treated group. Ten days after surgical removal of lacrimal gland, nictitating membrane and Harder's gland of the rabbit eyes, and corroding the conjunctiva with 50% trichloroacetic acid, the rabbit eyes showed typical dry eye signs. A lot of pathologic ultrastructural changes of the corneal epithelium were observed. Fourteen days after topically applying the three eye-drops, no significant effect was found on the ultrastructural changes of the dry eye corneal epithelium in the 0.1% bromhexine-treated and 50% Chinese medicinal herb-treated groups. However, in the 0.01% retinoic acid-treated eyes, normal microvilli and microplicae reappeared, denuded corneal epithelium was covered by new epithelial cells, no cell swelled, degenerated mitochondria recovered, basement membrane returned completely, and the completely recovered corneal epithelial cell count showed a significant difference compared with the control (P < 0.01). We conclude that removing the lacrimal gland, nictitating membrane and Harder's gland of rabbit eye, and corroding the conjunctiva with 50% trichloroacetic acid can result in rabbit dry eye and topically applying 0.01% retinoic acid can promote the recovery of the dry corneal epithelium.