Microglia-like or microglia: results of the weak silver carbonate staining method of del Rio-Hortega.

We investigated the character and origin of the newly described "microglia-like" cell in the mammalian organ of Corti after aminoglycoside intoxication. We replicated the neomycin-induced ototoxicity model in cochleae of neonatal Sprague-Dawley rats and used their brains as microglia positive controls. The weak silver carbonate staining method of del Rio-Hortega was used to identify the microglia-like cell. The microglia-like cell was confirmed by transmission electron microscope (TEM). Microglia in the brain were stained while rat microglia-like cells in the cochlea were unstained by the weak silver carbonate staining method of del Rio-Hortega. Because the microglia-like cell was unstained by the method of del Rio-Hortega, it is unlikely that the newly found cell is related to microglia.