Experimental Herpes Simplex Keratitis:  Early Alterations of Corneal Epithelium and Stroma

Epithelial and stromal changes in punctate lesions of rabbit corneas infected with herpes simplex virus (HSV) were studied by light and electron microscopy and measurements of epithelial intracellular and stromal potential differences were correlated with the histological observations. Virusinfected cells were enlarged, and the nuclear chromatin was marginated. Intracellular membrane potentials of epithelial cells in the punctate lesions were lower than normal. Nonenveloped viral particles were present in the nuclei of infected cells. Enveloped HSV particles were observed in inpocketings of the inner nuclear membrane, cytoplasmic tubules, extracellular spaces, and lying directly on basement membrane. The basement membrane was intact and of uniform thickness, even when polymorphonuclear leukocytes invaded the epithelial lesion. Numerous keratocytes with extensively developed endoplasmic reticulum were present in the superficial stroma immediately below the punctate lesions.