FACIAL-NERVE PARALYSIS INDUCED BY HERPES-SIMPLEX VIRUS IN MICE - AN ANIMAL-MODEL OF ACUTE AND TRANSIENT FACIAL PARALYSIS

We have been the first to succeed in producing an acute and transient facial paralysis simulating Bell's palsy, by inoculating herpes simple x virus into the auricles or tongues of mice. The KOS strain of the vi rus was injected into the auricle of 104 mice and the anterior two thi rds of the tongue in 30 mice. Facial paralysis developed between 6 and 9 days after virus inoculation, continued for 3 to 7 days, and then r ecovered spontaneously. The animals were painlessly sacrificed between 6 and 20 days after inoculation for histopathologic and immunocytoche mical study. Histopathologically, severe nerve swelling, inflammatory cell infiltration, and vacuolar degeneration were manifested in the af fected facial nerve and nuclei. Herpes simplex virus antigens were als o detected in the facial nerve, geniculate ganglion, and facial nerve nucleus. The pathophysiologic mechanisms of the facial paralysis are d iscussed in light of the histopathologic findings, in association with the causation of Bell's palsy.