Morphological changes induced by three aminoglycosides on the cochlear stria vascularis

Aminoglycosides are efficient antimicrobials commonly used in clinical practice. Their effects on the cells of the organ of Corti and the spiral ganglion neurons have been extensively studied. However, there are only a few reports concerning aminoglycoside-induced morphological changes on the stria vascularis. The purpose of this study was to describe morphological and morphometrical changes on the rat stria vascularis after a profound sensorineural hearing loss induced by three aminoglycosides (kanamycin, gentamicin and amikacin) followed by furosemide. To analyze the stria vascularis area and the number of blood capillaries per stria vascularis, cochleae from fourteen rats sampled at eight weeks after deafness and from four control animals were processed. Serial semi thin cochlear sections from the apical, upper middle, lower middle and basal turns were examined under a light microscope. The cochlear damage degree depended on the aminoglycoside. Mean stria vascularis areas for both kanamycin and gentamicin groups were lower than controls. The mean number of blood capillaries per stria vascularis was reduced for the three aminoglycoside-deafened groups as compared to control animals. For both variables, the most severe damage was observed for gentamicin-deafened animals, followed by kanamycin and amikacin.