The effect of corticosteroid against streptomycin ototoxicity.

The aim of this experimental study was to determine the possible protective role of corticosteroid in prevention of streptomycin-induced ototoxicity. Twenty-eight adult Wistar albino rats were divided into 4 groups: control (n = 7), streptomycin (n = 7), corticosteroid (n = 7), and streptomycin + corticosteroid (n = 7). Rats were tested with distortion product otoacoustic emissions (DPOAEs) in the beginning and at the end of the study. The animals in all groups were killed under general anesthesia on the 45th day after the last DPOAE measurements. Hearing results were analyzed statistically to determine differences in amplitudes of DPOAE. In addition, the cochleas of each rat were evaluated by histopathologic and immunohistochemical examination. Significant difference was not observed in cochlear hair cells in the control and corticosteroid groups, whereas severe degeneration of hair cells and increased apoptotic cells were observed in the streptomycin group. Moderate degeneration was observed in the streptomycin + corticosteroid group. The hair cells were partially intact. DP-gram of the streptomycin and streptomycin + corticosteroid groups was significantly deteriorated (P < 0.05). The coadministration of steroids with streptomycin, which has a serious ototoxic effect, did not lead to a limitation of this harmful effect.