title: Effect of Ascorbic Acid on Noise Induced Hearing Loss in Rats.
abstract: BACKGROUND
  After presbycusis, noise-induced hearing loss is the second most common cause of acquired hearing loss. Numerous studies have shown that high-intensity noise exposure increases free radical species; therefore, use of antioxidants to detoxify the free radicals can prevent cellular damage in the cochlea. We studied the potential hearing protective effect of different doses of ascorbic acid administered prior to noise exposure in rats.
  
  
  METHODS
  Twenty-four male albino Wistar rats were randomly allocated into four groups: groups A, B, and C received 1250, 250, and 50 mg/kg/day of ascorbic acid, respectively, and group D acted as the control group. After 14 days of ascorbic acid administration, the rats were exposed to noise (105 dB sound pressure level for 2 h). Distortion product otoacoustic emissions (DPOAE) were recorded prior to starting the ascorbic acid as baseline and 1 h after the noise exposure.
  
  
  RESULTS
  The amplitude decrease was 14.99 dB for group A, 16.11 dB for group B, 28.82 dB for group C, and 29.91 dB for the control group. Moderate and high doses of ascorbic acid significantly reduced the transient threshold shift in the rats.
  
  
  CONCLUSIONS
  The results of present study support the concept of cochlea protection by antioxidant agents. This dose-dependent protective effect was shown through the use of ascorbic acid treatment prior to noise exposure.
authors.affiliation: Industrial Diseases Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors.forename: Ziba
authors.initials: Z
authors.lastname: Loukzadeh
authors.affiliation: Industrial Diseases Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors.forename: Abolfazl
authors.initials: A
authors.lastname: Hakimi
authors.affiliation: Department of Physiology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors.forename: Mansour
authors.initials: M
authors.lastname: Esmailidehaj
authors.affiliation: Industrial Diseases Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors.forename: Amir Houshang
authors.initials: AH
authors.lastname: Mehrparvar
keywords: Ascorbic acid; Hearing loss; Noise; Otoacoustic emission.