Efficacy of Systemic Methylprednisolone and Intratympanic Dexamethasone in Rats with Noise İnduced Hearing Loss

İngilizce (OpenAlex)

ABS TRACT Objective: To evaluate the audiological and electron microscopic (EM) effects of systemic methylprednisolone and intratympanic dexamethasone (IT DXM) in rats with noise induced hearing loss.Material and Methods: Thirty-one adult female Wistar albino rats were randomized into 3 groups as Group I (n=8), Group II (n=11) and Group III (control, n=12).The animals were exposed to white noise at a frequency of 1-10 kHz and 110 dB sound pressure level for 8 hours in a free environment.Distortion product otoacoustic emission (DPOAE) measurements were performed before and after the noise.Group I received 0.8 mg/day IT DXM and Group II had 1 mg/kg/day intraperitoneal methylprednisolone for 7 days.Intraperitoneal saline solution was administered to Group III.DPOAE tests were repeated on the 7 th and 21 st days.After animals were sacrified on the 21 st day, their cochleas were examined under EM.Statistical analysis was performed for the DPOAE measurements.Results: Measurement of the first day to 7 th and 21 st days were compared in all groups separately.Statistical significant recovery was observed in the frequencies of 5,000-6,000 Hz (p<0.05) in Group I and in the frequencies of 6,000-8,000 Hz (p<0.05) in Group II.The measurements were similar in control group for all frequencies on the 1 st , 7 th and 21 st days (p>0.05).Groups I and II showed more stable and larger number of stereocilia compared to Group III on EM examination.Conclusion: IT DXM and systemic methylprednisolone are effective at certain frequencies in noise induced hearing loss.The combined use of both methods may provide additional benefits.