Permeability of Horseradish Peroxidase in the Rabbit Corneal Epithelium

Horseradish peroxidase has been used in the cornea as a histochemical tracer for both light and electron microscopy. When the rabbit corneae, as little damaged as possible, were mounted between two lucite chambers containing a nutrient solution, and exposed to this enzyme on the epithelial side, no peroxidase reaction products were detected below the epithelial surface. When the endothelial side had been exposed for one hour or more, the enzyme had moved across the endothelium, the Descemet's membrane, the stroma, and up between the epithelial cells to the zonulae occludentes between the cells of the most superficial layer, adjacent to the tear film.