An Evaluation of the Protective Effects of Thymoquinone on Amikacin-Induced Ototoxicity in Rats

Abstract

Objectives. In this study we investigated the probable protective effects of thymoquinone on amikacin-induced ototoxicity in rats. Methods. Thirty-two healthy rats were divided into four groups (amikacin, amikacin+thymoquinone, thymoquinone, and no treatment). Thymoquinone was fed to the rats via oral gavage in a dose of 40 mg/kg/day throughout the study period of 14 days. Amikacin was given by the intramuscular route in a dose of 600 mg/kg/day. Audiological assessment was conducted by the distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) tests, administered to all rats at the beginning of the study, and also on days 7 and 15. Biochemical parameters were calculated at the termination of the study to evaluate the oxidative status. Results. There were significant decreases in DPOAE values and significant increases in ABR thresholds of the amikacin group on days 7 and 15, as compared to the amikacin+thymoquinone group. While ABR thresholds of the amikacin group increased significantly on days 7 and 15 as compared to their initial values, there were no significant differences between the initial and the 7th and 15th day values of ABR thresholds in the amikacin+thymoquinone group. Total oxidant status and oxidative stress index values of the amikacin+thymoquinone group were significantly lower than those of the amikacin group. Total antioxidant status values of the amikacin+thymoquinone group were significantly higher than those of the amikacin group. Conclusion. Our study has demonstrated that the ototoxic effect brought forth by amikacin could be overcome with the concurrent use of thymoquinone.