Preconditioning by the inhalation of pure oxygen protects rat’s cochlear function against noise-induced hearing loss
Background: Occupational noise-induced hearing loss (ONIHL) is a hearing disorder that affects workers all over the world. Preconditioning with several mild or less potent stressors will effectively prevent the development of noise-induced hearing loss. This study investigated the possible preventive effects of normobaric hyperoxia preconditioning on preventing the noise-induced hearing impairment in the rats. Materials and Methods: Four groups of male Wistar rats served as controls, exposed to normobaric oxygen, noise, or oxygen plus noise. The noise exposure lasted for 6 hours/day, 5 days/week, 4 weeks and the preconditioning conducted by inhalation of pure oxygen (95%) for 3 hours/day, 6 days/week, 1 week in a chamber prior to noise exposure. A bandpass noise of 100dB SPL centered at 8 KHz was used for noise exposure. Click and tone burst auditory brainstem responses (ABR) and distortion product otoacoustic emissions (DPOAE) audiograms were recorded in order to evaluate the level of hearing loss among the subjects before the beginning and 4 weeks post-exposure. Statistical analysis was performed using SPSS. Results: The weekly pre-conditioning by normobaric hyperoxia significantly reduced the ABR threshold shifts and restored the amplitudes of DPOAE (P < 0.001). The control group did not show any difference in terms of DPOAE and ABR tests during and after the exposure (P > 0.050). Conclusions: The preconditioning successfully protected the rats’ hearing by maximizing and developing tolerance to ischemia and hypoxia caused by the noise. The application of such preconditioning is then considered as a possible complementary preventive solution.
This paper presents noise problems associated with the use of air-turbine drills in dental practice. Two hundred and fifty dentists (male and female) were randomly selected from the faculty of dentistry as well as the dentists who worked private in Tehran. The results indicated that the mean value of sound pressure level produced by the high-speed drills was 69.1 db. Most of the energy from...متن کامل
Acrylonitrile produces transient cochlear function loss and potentiates permanent noise-induced hearing loss.
There is growing evidence that agents that produce oxidative stress in the cochlea have significant ototoxic potential by themselves and can potentiate noise-induced hearing loss as well. Acrylonitrile (ACN) metabolism entails conjugation with glutathione, resulting in rapid and pronounced depletion of this important antioxidant in many organs including brain, liver, and kidney. ACN metabolism ...متن کامل
Introduction: 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 ascorb...متن کامل
Recent studies on animal models have shown that noise exposure that does not lead to permanent threshold shift (PTS) can cause considerable damage around the synapses between inner hair cells (IHCs) and type-I afferent auditory nerve fibers (ANFs). Disruption of these synapses not only disables the innervated ANFs but also results in the slow degeneration of spiral ganglion neurons if the synap...متن کامل
Activation of SIRT3 by the NAD⁺ precursor nicotinamide riboside protects from noise-induced hearing loss.
Intense noise exposure causes hearing loss by inducing degeneration of spiral ganglia neurites that innervate cochlear hair cells. Nicotinamide adenine dinucleotide (NAD(+)) exhibits axon-protective effects in cultured neurons; however, its ability to block degeneration in vivo has been difficult to establish due to its poor cell permeability and serum instability. Here, we describe a strategy ...متن کامل
Introduction: Exposure to hazardous noise induces one of the forms of acquired and preventable hearing loss that is noise-induced hearing loss (NIHL). Considering oxidative stress as the main mechanism of NIHL, it is possible that myricetin can protect NIHL by its antioxidant effect. Therefore, the present study aimed to investigate the preventive effect of myricetin on NIHL. <br /...متن کامل
دوره 6 شماره 4
صفحات 215- 224
تاریخ انتشار 2017-10
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