The audilogical and histological effects of nimodipine and dexametasone in noised exposed rats

In our study rats were seperated in 5 different group and first group recieved neither noise nor treatment. Second group was exposed to noise and received saline solution. Third group recieved noise and nimodipine treatment. Forth group received noise and dexamethasone treatment. Fifht group exposed noise and received both nimodipine and dexamethasone treatments.Study was conducted with auditory brainstem response (ABR) and distortion product otoacoustic emmisions (DPOAE) tests. Outer hair cells of organ of corti, spiral ganglion and stria vascularis were evaluated in hematoxilene-eosine stain. Moreover, TUNEL (terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling) method was used to determine the existance of apoptosis. In our study, all the hearing levels were found similar in first examination but after the noise exposure hearing thresholds of 2nd, 3rd, 4th, 5th groups were significantly differed from the group 1. 3rd, 4th, 5th groups didn't show any significant difference in 7th and 21st days of the trial. Number of histological samples were insufficient to provide a result. Few histological results showed significant significancy but other histological and functional test didn't support the related result.