Promotion of noise-induced cochlear injury by toluene and ethylbenzene in the rat.

نویسندگان

  • Laurence D Fechter
  • Caroline Gearhart
  • Sherry Fulton
  • Jerry Campbell
  • Jeffrey Fisher
  • Kwangsam Na
  • David Cocker
  • Alisa Nelson-Miller
  • Patrick Moon
  • Benoit Pouyatos
چکیده

Ethylbenzene + toluene are known individually to have ototoxic potential at high exposure levels and with prolonged exposure times generally of 4-16 weeks. Both ethylbenzene + toluene are minor constituents of JP-8 jet fuel; this fuel has recently been determined to promote susceptibility to noise-induced hearing loss. Therefore, the current study evaluates the ototoxic potential of combined exposure to ethylbenzene + toluene exposure in a ratio calculated from the average found in three laboratories. Rats received ethylbenzene + toluene by inhalation and half of them were subjected simultaneously to an octave band of noise (OBN) of 93-95 dB. Another group received only the noise exposure which was designed to produce a small, but permanent auditory impairment while an unexposed control group was also included. In two separate experiments, exposures occurred either repeatedly on 5 successive days for 1 week or for 5 days on 2 successive weeks to 4000 mg/m(3) total hydrocarbons for 6 h based upon initial pilot studies. The concentration of toluene was 400 ppm and the concentration of ethylbenzene was 660 ppm. Impairments in auditory function were assessed using distortion product otoacoustic emissions and compound action potential testing. Following completion of these tests, the organs of Corti were dissected to permit evaluation of hair cell loss. The uptake and elimination of the solvents was assessed by harvesting key organs at two time points following ethylbenzene + toluene exposure from additional rats not used for auditory testing. Similarly, glutathione (GSH) levels were measured in light of suggestions that oxidative stress might result from solvent-noise exposures. Ethylbenzene + toluene exposure by itself at 4000 mg/m(3) for 6 h did not impair cochlear function or yield a loss of hair cells. However, when combined with a 93-dB OBN exposure combined solvent + noise did yield a loss in auditory function and a clear potentiation of outer hair cell death that exceeded the loss produced by noise alone. No evidence was found for a loss in total GSH in lung, liver, or brain as a consequence of ethylbenzene + toluene exposure.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

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 impairm...

متن کامل

Cancer Risk Assessment Benzene, Toluene, Ethylbenzene and Xylene (BTEX) in the Production of Insulation Bituminous

Benzene, Toluene, Ethyl Benzene and Xylene are volatile organic compounds (VOCs) with approximately similar physical and chemical characteristics. Benzene and Ethyl-benzene are known carcinogen as well as they affect the circulatory, nervous, and reproductive and respiratory systems. Toluene and Xylene also damage the nervous and reproductive systems. The main purpose of this study is to determ...

متن کامل

The Effect of Celecoxib, a Cyclooxygenase-2 Inhibitor on Noise- Induced Hearing Loss

Objective(s): Noise-induced hearing loss (NIHL) is the major cause of acquired hearing loss.  Celecoxib, a cyclooxygenase-2 (COX-2) inhibitor, is a non- steroidal anti- inflammatory drug (NSAID) with known antioxidant and antineoplastic activity. Therefore, we monitored the extent of temporary noise- induced threshold shifts (TTS) and cochlear damage caused by high level 4- kHz noise exposure t...

متن کامل

Passive Sampling of Aromatic Hydrocarbons Toluene, Xylene and Ethylbenzene Using Activated Carbon Fabric in Ambient Air of Tehran

Background & Objectives: Air pollution is one of the most important environmental problems in large cities. Aromatic hydrocarbons as volatile organic compounds (VOCs) have been listed in Hazardous Air Pollutants (HAPs) by Environmental Protection Agencies (EPA). The aim of this study is Passive sampling and determination of aromatic hydrocarbons (AHs) toluene, xylene and ethylbenzene using ...

متن کامل

Anaerobic degradation of ethylbenzene and toluene in denitrifying strain EbN1 proceeds via independent substrate-induced pathways.

Denitrifying strain EbN1 utilizes either ethylbenzene or toluene as the sole source of organic carbon under strictly anoxic conditions. When cells were grown on ethylbenzene, 1-phenylethanol and acetophenone were detected in the culture supernatant. However, these two compounds were not observed when cells were grown on benzoate. Growth on ethylbenzene, 1-phenylethanol, or acetophenone strictly...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Toxicological sciences : an official journal of the Society of Toxicology

دوره 98 2  شماره 

صفحات  -

تاریخ انتشار 2007