In a previous report (Ear Res Jpn 13: 161-163, 1982), we described the ultrastructural features of the labyrinthitis caused by Sendai virus infection. This study further demonstrated the histopathological aspects of viral lesions in the vestibular labyrinth in 7 guinea pigs (3 cyclophosphamide-treated and 4 steroid-treated) with cochlear lesions.
In the vestibular membranous labyrinth, Sendai virus mainly infected the nonsensory regions but the sensory epithelia were spared. In the former regions, the saccular wall was especially susceptible to the infection and collapse of the saccular membrane was found in 2 ears with severe cochlear lesions. On the other hand, the utricular wall was more resistant to the viral infection and its epithelial layer was rarely involved. Factors responsible to such different susceptibility of the saccular and utricular walls to the viral infection are discussed.
