Alpha-tocopherol role in prevention of noise-induced hearing loss in rabbit

Noise-induced hearing loss (NIHL) is one of the most common occupational diseases that can lead to disability and losses in the workplace. Metabolic disturbances induced by free radicals formation in the cochlea during the intense noise exposure can play an essential role in the development of NIHL. This study aimed to evaluate the preventive effect of α-tocopherol administration as a free radical scavenger agent against the NIHL in rabbits. In this experimental study، 24 male adult white rabbits were divided into four groups: control; noise-exposured (100 dB broadband noise with 500-5700 Hz for 40 h); noise-exposured plus α-tocopherol administration (50 mg/kg per day، ip) and no-exposure and α-tocopherol administration groups. Audiometric test of rabbits was assessed by the auditory brainstem response method in three stages. Administration of α-tocopherol provided a significant attenuation in temporary and permanent hearing threshold shifts at 1-8 KHz frequencies to 14، 13، 10، 7 and 14، 14، 12، 7 dB، respectively. Results show that α-tocopherol، as an antioxidant agent، can provide protective effects against temporary and permanent hearing loss resulting from noise exposure in rabbit. Further studies in human are needed.