A convenient rabbit model of ocular epithelium damage induced by osmotic dehydration.

Dry eye is an ocular disease clinically associated with corneal epithelium damage and arises acutely or chronically from dehydration of the ocular surface. We provide herein a novel in vivo model of corneal epithelium damage, in which the corneal surface was entirely covered with a sugar powder to provoke the rapid removal of corneal surface liquid. In this animal model, such corneal damage as can be fluorometrically detected was observed immediately after 20-minute hyperosmotic treatment, reached a maximum 6 hours later, and then gradually declined to complete recovery at Hour 126. Recovery of the damaged corneas produced by hyperosmotic stress was significantly accelerated by treatment with 0.1% sodium hyaluronate, a dry eye remedy in Japan. Thinning or partial erosion of the epithelial cell layers was histopathologically demonstrated in and around the sugar powder-applied area but the posterior stromal cell layer remained intact, indicating that the present rabbit in vivo model may be used to conveniently screen therapeutics against acute ocular diseases with corneal epithelium damage. In addition, microscopic observations of TUNEL-stained thin-sections of the damaged corneas indicated that apoptotic cell death, but not any inflammatory reactions, may be at least partially responsible for the hyperosmolarity-induced destruction of the corneal epithelium.