Ototoxic effect of nitromin and some congenital deaf animal cochlea. An electron microscopical study

Abstract

The ototoxic action of nitromin on guinea pigs and mice was studied, Shaker-l-mice and Hedlund white mink cochlea were also studied with the comparison of nitromin intoxicated cochlea. Nitromin was found to be more toxic than kanamycin, streptomycin and gentamicin with regard to their dosages. Toxic reactions were mainly observed in the cochlear sensory epithelia. Degeneration appeared first in the outer hair cells in the basal turn of the cochlea starting with the formation of whorls and proliferation of smooth endoplasmic reticula and ending with the complete degeneration of the sensory cells, but the stria vascularis showed little change. Even after the disappearance of the hair cells, some efferent nerve endings were still present in the organ of Corti. Shaker mice have a fairly normal stria vascularis with normal filling of scaly media but show severe degeneration of organ of Corti. This cochlea shows pathological changes somewhat similar to those of ototoxic antibiotics intoxicated cochlea. On the other hand, Hedlund white mink showed the degeneration of the organ of Corti caused by severe degeneration of the stria vascularis and collapse of scaly media. We have demonstrated similar final cochlear degeneration following different pathological pathways in three species of animals. © 1971 Springer-Verlag.