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

Figure 3

Epifluorescence analysis of the OC at 12 weeks after drug administration. Hair cells (MyosinVIIa, red) and the peripheral auditory nerve (Neurofilament, green) were observed at three parts of the cochlea that are tonotopically responsible for 8, 16, and 32 kHz of hearing. The control group showed intact hair cells and nerve fibers. KP group showed intact IHCs and a few defects of OHCs at three different parts. Nerve fiber connections from hair cells to SGCs were disrupted in the KP group. In the KG and KI groups, IHCs and OHCs completely disappeared and only fragments of nerve fibers were observed. The three groups were kanamycin percutaneous (KP), kanamycin gelfoam (KG), and kanamycin RW injection (KI). The white dotted lines represent the IHC place. Scale bar is 100 um.