Secondary Degeneration of Auditory Neurons after Topical Aminoglycoside Administration in a Gerbil Model

Figure 5

Histologic analysis of the OC and SGCs at four different parts of the cochlea at 12 weeks after drug administration. At 12 weeks after drug administration, the OC was intact in the KP group, but the KG group showed a flat epithelium without any sensory cells at all parts except the high middle part. The KI group showed a disrupted OC at all parts of the cochlea. The KP group showed no reduction of SGC density, showing a similar result to the control group. However, the KG group showed sparse SGCs at all parts of the cochlea, which is more severe than 4 weeks after drug administration. For the KI group, more severe depletion of SGCs was found at all parts of the cochlea. The three groups were kanamycin percutaneous (KP), kanamycin gelfoam (KG), and kanamycin RW injection (KI). Scale bar represents 100 um.