FLUCTUATING HEARING-LOSS FOLLOWING IMMUNE-REACTION IN THE ENDOLYMPHATIC SAC OF GUINEA-PIGS

This study has investigated immune injuries to the inner ear auditory system of guinea pigs. Following secondary antigen challenge to the en dolymphatic sac, the mean hearing threshold significantly increased in the early phase from day 1 to day 3 and thereafter recovered. In the early phase, hearing threshold significantly increased simultaneously to the elevation of perilymph antibody levels. The size of hydrops was not the only factor that causes an increase in hearing loss as well a s in AP/SP ratio. Scale-out hearing loss was seen in 2 animals with se vere degeneration of the stria vascularis as well. as the organ of Cor ti associated with the inflammatory cellular infiltration especially i n the perilymphatic space, even in the absence of keyhole limpet hemoc yanin antigen in the cochlea. On the other hand, control animals did n ot suffer hearing loss. These results suggest that an immune reaction in the endolymphatic sac is a possible pathogenic etiology of Meniere' s disease or sudden deafness.