An animal model of type-1 herpes simplex virus infection of facial nerve.

As the pathogenesis of Bell's palsy, herpes simplex virus (HSV) infection has been suggested on the basis of several serological studies. To clarify and analyse the pathogenic mechanisms of this disease, guinea pigs were inoculated with type-1 HSV through natural infection routes into the peripheral areas innervated by facial nerve, and nervous tissues were examined by histopathological and immunohistochemical methods. HSV-I infection in the nasal mucosa, tongue, oral muscles and auricles brought about neither clinical facial palsy nor disturbed Preyer or corneal reflexes, but viral antigens in the inoculated peripheral areas, facial and trigeminal ganglia and pons with inflammatory cell response, hemorrhages and degeneration and necrosis. Cyclophosphamide treatment resulted in disturbed Preyer and corneal reflexes and enhanced the incidence of antigen appearance and histopathological changes.