Cytoarchitectural Changes in Corti's Organ after Kanamycin Treatment and Acoustic Trauma

Changes in the cytoarchitectural pattern of the organ of Corti were studied in two groups of guinea pigs. One had been treated with kanamycin in doses of 200–400 mg/kg/day for 5–20 days. The other group had been exposed to tones of 500–4000 cps at 140–150 dB SPL. Examination of surface preparations of the organ of Corti by phase-contrast microscopy revealed loss of outer hair cells in both groups of animals. In the kanamycin group, the greatest loss was at the basal end of the organ of Corti. In the acoustic-trauma group, the site of loss varied somewhat, as might be expected, with the exposure frequency, but was greatest in the first and second turns. Severe destruction was visible under the dissecting microscope, without the aid of greater magnification. In acoustic trauma, loss of pillar cells was also seen, whereas kanamycin caused loss of Caludius cells in the basal turn. The results are illustrated with photomicrographs and maps of the organ of Corti.