ABSTRACT THE PROTECTIVE EFFECT OF THYMOQUINONE TREATMENT TO THE INNER EAR DAMAGE CAUSED BY ACOUSTIC TRAUMAYENİGÜN A, The effect of thymoquinone treatment on the rats with inner ear damage caused by acoustic trauma, Bezmialem Medical School, Department of Ear, Nose, and Throat, İstanbul, 2012.Objective:The goal of the study was to investigate whether thymoquinone has any protective effect against to inner ear damage due to acoustic trauma.Material and Methods:This study was performed during January and February in 2012 at Bezmialem Medical School Department of Ear, Nose, and Throat. 32 male Wistar Albino rats were used in this study. The rats were divided into four groups. The 1st group was only exposed to acoustic trauma (105 dB SPL white band for 4 hour). The 2nd group was exposed to acoustic trauma then treated with thymoquinone (10 mg/kg i.p.). The 3rd group was only treated with thymoquinone (10 mg/kg i.p.), and The 4th group was the control group that was only treated with intra peritoneal saline injection. The basal hearing measurements of the rats were measured by Distortion-product otoacoustic emission (DPOAE) and Auditory brainstem response (ABR) methods. Then, two groups were exposed to acoustic trauma with 105 dB SPl white band noise for 4 hour. Thymoquinone was started to be given to the rats 24 hr before the trauma and continued to be given during 10 days after trauma. DPOAE and ABR tests were employed to all groups at 1st, 5th, and 10th days of the study. At the end of the study, all rats were sacrificed and blood samples were evaluated for AOPP, SOD, and MDA values.Outcomes:In our study, it was observed that the effect of acoustic trauma was still lasting when the trauma applied group was tested with DPOAE and ABR after the 1, 5 and 10 days of trauma application. Conversely, DPOAE and ABR results of the 2nd group that had trauma and treated with thymoquinone showed positive effect of thymoquinone at 5th and 10th days of application with test values close to pretrauma. When the 3rd group which only given thymoquinone was investigated, we observed that thymoquinone did not have any negative effect on hearing. Besides, control group?s DPOAE and ABR tests showed stable results during the study. Moreover, MDA values (µmol/L) of trauma applied and thymoquinone treated group were significantly lower than the values of only trauma exposed group (p<0,05). SOD values (U/ml) of trauma applied and thymoquinone given group were significantly higher (p<0,05) compared to only trauma exposed group. A significant difference was not detected between the groups for the AOPP (µmol/L) values (p= 0,06).Conclusion:Acoustic trauma is a pathology that is experienced frequently and comprises many problems in terms of health and cost. Thymoquionone was demonstrated to be an otoprotective substance that can be used to prevent and acoustic trauma as well as it can be supplied and applied easily.Key Words:Acoustic trauma, Thymoquinone, Otoacoustic emission, Auditory brainstem response.