Impression cytology of herpetic simplex keratitis in rabbits.

PURPOSE To use impression cytology to examine the structural changes in corneal epithelial cells infected with the herpes simplex virus in rabbit eyes. METHODS Corneal surfaces of 7 rabbits were scratched using a 25-gauge needle. Herpes simplex virus (type 1, Kos strain) was inoculated to the injured cornea. As the corneal diseases were observed using slit lamp biomicroscopy, impression cytology was performed for 18 days after inoculation. Specimens were stained with hematoxylin-eosin and examined using optical microscopy. RESULTS Corneal lesions consisted mainly of round epithelial cells, inflammatory cells, ballooning cells, multinucleated giant cells, and various inclusion bodies. Over time, the comeal epithelial cells peeled away as a result of corneal edema in the comeal lesions. Dendritic lesions were also observed. In the recovery phase, the number of detached cells and infiltrated inflammatory cells decreased. CONCLUSIONS It was presumed that dendritic lesions might have been formed at the scratched cornea region, thereby aggravating the epithelial cells falling off as a result of the infiltration of inflammatory cells. These cytopathologic effects occur in experimental herpes simplex keratitis.