Year: 2012
Type: article
Abstract: Objective: Noise causes damage of the auditory system leading to hearing loss.The aim of this study was to investigate preventive role in noise induced hearing loss (permanent threshold shift model) and anti-apoptotic effects of two different dose of melatonin. Materials and Methods:Forty-four adult Sprague-Dawley rats were randomly divided into six groups.Narrow band noise for 6 hours was used to induce noise induced permanent threshold shift model.We used two different doses (0.4mg/kg, 4mg/kg) of melatonin, which were all injected intraperitonially (IP) four times.IP injection was given one day before, immediately before first and second noise exposure and one time between first and second noise exposure (total four times).Group NO was exposed to noise and treated with vehicle.Group NL and NH was exposed to noise and treated with either low dose (NL) or high dose (NH) melatonin.The hearing thresholds change and orphological assessment for hair cell damage were performed.Apoptosis activity was also compared using Western blotting of caspase 3 in each group. Results:We observed consistent threshold increase up to 90 dB SPL until 3 weeks with current noise exposure method.Rats treated with melatonin showed less hearing loss after noise exposure than untreated rats.Outer Hair cell loss was also attenuated in melatonin treated rats under SEM observation.Melatonin reduced caspase 3 activity after noise exposure.However, there was no difference between two different doses (NL, NH).Conclusion: Preventive treatment with melatonin attenuates hearing threshold shift by reducing outer hair cell damage.This protective effect was shown to with reduced proapoptotic caspase 3 protein.We could not find additional protective effects with higher dose compared to lower dose in this study.
Institutions: Dankook University, University of Illinois Urbana-Champaign
Language: English
Subfield: Sensory Systems
Field: Neuroscience
Domain: Life Sciences
Open Access status: bronze
Funder: Dankook University
OpenAlex ID: W3042248733