A new oral otoprotective agent. Part 1: Electrophysiology data from protection against noise-induced hearing loss

Background: Data from animal studies show that antioxidants can compensate against noise-induced stress and sensory hair cell death. The aim of this study was to evaluate the otoprotection efficacy of various versions of orally administered Acuval 400 (R) against noise damage in a rat animal model. Material/Methods: Fifty-five Sprague Dawley rats were divided into 4 groups: A) noise-exposed animals; B) animals exposed to noise and treated with the Acuval; C) animals exposed to noise and treated with a combination of Coenzyme Q10 and Acuval; D) animals treated only with Acuval and Coenzyme Q10 and with no exposure to noise. All solutions were administered orally 5 times: 24 and 2 hrs prior to noise exposure, and then daily for 3 days. The auditory function was assessed by measuring auditory brainstem responses (ABR) in the range from 2 to 32 kHz at times =1, 7, 14 and 21 days after noise exposure. Results: At low frequencies (click and 4 kHz) animals from both A and B groups showed significant threshold shifts in the majority of the tested frequencies and tested times. For the same frequencies, animals from group C presented threshold levels similar to those from group D. At frequencies >8 kHz the protective performance of the 2 Acuval groups is more clearly distinguished from the noise group A. At 32 kHz the 2 Acuval groups perform equally well in terms of otoprotection. Animals in Group D did not show any significant differences in the hearing threshold during the experiment. Conclusions: The data of this study suggest that a solution containing Coenzyme Q10 and Acuval 400 (R), administered orally, protects from noise-induced hearing loss.