Ultrastructure of the Optic Neuritis Induced by Herpes Simplex Virus-1 Injection in Rabbits

ABSTRACT

PURPOSE: This study was performed to investigate the ultrastructural changes of the optic nerve after intravitreal injection of herpes simplex virus-1. METHODS: Herpes simplex virus was separated from the culture media after observing the cytopathic effect on cultured vero cells. Viruses were then injected on the optic nerve head of 21 rabbit eyes. Eyes were enucleated at 1, 2, 3, 5, 7, 10, and 14 days after injection of herpes simplex virus and examined under the electron microscope. RESULTS: The intranuclear inclusion body was noted in eyes examined at 2 days after injection. The histopathological changes were perivascular infiltration of inflammatory cells, cytoskeletal degeneration of large diameter of myelinated nerve, demyelination of axonal nerve fiber, and the accumulation of mitochondria within axonal nerve fiber. CONCLUSIONS: These results suggest that optic neuritis may be induced by herpes simplex virus. The accumulation of mitochondria may be related to the interruption of the axonal transport through the axonal nerve fibers of optic nerve.