Investigation of preservative effects of resveratrol in acoustic trauma-related sudden hearing loss with mechanisms

Acoustic trauma is defined as the process in which the sound energy coming to the ear is too high and the hearing loss occurs. Acoustic trauma initiates a number of events that result in apoptosis and necrosis in cochlea auditory haired cells. Using the autoacoustic emission (DPOAE) test, which is one of the audiologic examinations to assess hearing impairment that occurs as a result of these events, in which we can assess the external-hair cell damage. Cochlear hypoxia caused by acoustic trauma leads to the release of reactive oxygen species from marginal cells in stria vascularis and causes changes in arachidonic acid, phospholipase A2, total cyclooxygenase (COX), and prostaglandin E2 levels in the cochlea. Resveratrol has found that antioxidant and antiinflammatory effects and reduce COX-2 levels. The level of hearing assessed with the help of the DPOAE, the mechanism of protective effect of resveratrol on acoustic trauma has been investigated. In our study, 45 female Wistar rats were used. There were 15 animals in each group; Control group, Acoustic trauma group and Acoustic trauma and Resveratrol treatment group. To produce acoustic trauma, rats were exposed to noise for 24 hours continuous 115 dB SPL white noise. Acoustic trauma group was given saline by gavage and Resveratrol group was given for 3 weeks 5 mg / kg / day resveratrol by gavage before noise. 24 hours after noise was applied, DPOAE was tested under anesthesia and the rats were sacrificed then the cochleas were removed. Cohleas were homogenized and arachidonic acid, total COX, prostaglandin E2, phospholipase A2 levels were measured. 24 hours continuous 115dB white noise exposure caused acoustic trauma at high frequency. Protective effect of resveratrol in acoustic trauma at 6000Hz and 10000Hz has been demonstrated. After acoustic trauma, PLA2 levels were significantly increased at 24 hours in the cochlea. A significant decrease in AA levels was noted at 24 hours after the acute trauma in the cochlea. Resveratrol has been shown to significantly alter PLA2 levels after acoustic trauma. The presence of a limited number of studies on the protective effect of resveratrol in acoustic trauma and the observed protective effect of resveratrol in certain frequencies in our study, observing changes in the role of AA pathway in the acoustic trauma mechanism are thought to contribute to increase the studies in this area.