Amikacin intoxication induces apoptosis and cell proliferation in rat organ of Corti.

Recently, an attempt at cochlear hair cell neodifferentiation has been reported in amikacin-treated rats. In the present study, we aimed to ascertain whether hair cell losses are mediated by apoptosis and whether cell proliferation occurs in damaged intoxicated cochleas. The results show that apoptosis is responsible for hair cell losses and that cell proliferation occurs in the region of the outer spiral sulcus but not in the region of Deiters cells and pre-existing hair cells. We suggest that cell proliferation maintains a certain homeostasis in the number of non-sensory cells and participates in epithelial scar formation. Neodifferentiated cells therefore probably arise from direct transdifferentiation, which could be triggered by phagocytosis of apoptotic bodies.