Effects of exogen steroids on auditory system in prenatal term, an experimental animal study

2. ABSTRACTTHE EFFECTS OF EXOGEN STEROIDS ON AUDITORY SYSTEM IN PRENATALTERM, AN EXPERIMENTAL ANIMAL STUDYThe aim of this study to investigate whether to be exposed to the exogendexametasone in prenatal term cause the oversensitivity in the auditory system and toexamine whether the antioxidant agents prevent the possible damages in inner ear byelectrophysiologic and microscopic methods.After 12 Sprague-Dowley female rats were impregnate, dexametasone wasapplied to half of the subjects and the distiled water was applied to remnant subjects.The real subjects were obtained with the born of the offsprings and all subjects wereexposed to 110 dB noise for four hours on two months old. These subjects weredivided into eight groups according to exposing to exogen dexametasone andappliying manner of the antioxidant agents. Grup 1: 0.1 mg/kg/day distiled waterinjected to mothers. Grup 2: 0.1 mg/kg/day distiled water injected to mothers and200 mg/kg aminoguanidine injected to itself. Grup 3: 0.1 mg/kg/day distiled waterinjected to mothers and 30 µmol/kg CAPE injected to itself. Grup 4: 0.1 mg/kg/daydistiled water injected to mothers and 100 mg/kg EGb-761 injected to itself. Grup 5:0.1 mg/kg/day dexametasone injected to mothers. Grup 6: 0.1 mg/kg/daydexametasone injected to mothers and 200 mg/kg aminoguanidine injected to itself.Grup 7: 0.1 mg/kg/day dexametasone injected to mothers and 30 µmol/kg CAPEinjected to itself. Grup 8: 0.1 mg/kg/day dexametasone injected to mothers and 100mg/kg EGb-761 injected to itself.The hearing levels of all subjects were determined one week before noise, 48hours after noise and two months after noise. After one month, all subjects weredecapitated for immunohistochemical and electron microscopic evaluation.Whilethere was no statistical significance between groups which exposed and not exposedto exogen dexametasone before noise application, after noise application theelevation of hearing levels of subjects which exposed to exogen dexametasone wasstatistically significant (p<0.05). According to immunohistochemical datas, theseantioxidant agents affirmative effects on oversensitive auditory system. According toelectron microscopic evaluation, exogen dexametasone cause the oversensitivity incochlea againist outer effects like noise.Key Words: Aminoguanidine, CAPE, EGb-761, Dexametasone, Prenatal Treatment11