1
|
Yeo XY, Kwon S, Rinai KR, Lee S, Jung S, Park R. A Consolidated Understanding of the Contribution of Redox Dysregulation in the Development of Hearing Impairment. Antioxidants (Basel) 2024; 13:598. [PMID: 38790703 PMCID: PMC11118506 DOI: 10.3390/antiox13050598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/26/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024] Open
Abstract
The etiology of hearing impairment is multifactorial, with contributions from both genetic and environmental factors. Although genetic studies have yielded valuable insights into the development and function of the auditory system, the contribution of gene products and their interaction with alternate environmental factors for the maintenance and development of auditory function requires further elaboration. In this review, we provide an overview of the current knowledge on the role of redox dysregulation as the converging factor between genetic and environmental factor-dependent development of hearing loss, with a focus on understanding the interaction of oxidative stress with the physical components of the peripheral auditory system in auditory disfunction. The potential involvement of molecular factors linked to auditory function in driving redox imbalance is an important promoter of the development of hearing loss over time.
Collapse
Affiliation(s)
- Xin Yi Yeo
- Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore;
- Department of Medical Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
| | - Soohyun Kwon
- Department of Medical Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
- Department of BioNanotechnology, Gachon University, Seongnam 13120, Republic of Korea
| | - Kimberley R. Rinai
- Department of Life Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
| | - Sungsu Lee
- Department of Otolaryngology-Head and Neck Surgery, Chonnam National University Hospital and Medical School, Gwangju 61469, Republic of Korea;
| | - Sangyong Jung
- Department of Medical Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
| | - Raekil Park
- Department of Biomedical Science and Engineering, Gwangju Institute of Science & Technology (GIST), Gwangju 61005, Republic of Korea
| |
Collapse
|
2
|
Loukzadeh Z, Houshang Mehrparvar A, Razmjooei Z, Ghoveh Nodoushan MA, Vakili M. Effect of noise and organic solvents on acoustic stapedial reflex. HEARING, BALANCE AND COMMUNICATION 2023. [DOI: 10.1080/21695717.2023.2172271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
- Ziba Loukzadeh
- Industrial Diseases Research Center, Center of Excellence for Occupational Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Amir Houshang Mehrparvar
- Industrial Diseases Research Center, Center of Excellence for Occupational Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Zhale Razmjooei
- Industrial Diseases Research Center, Center of Excellence for Occupational Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohammad Ali Ghoveh Nodoushan
- Department of Occupational Health, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mahmood Vakili
- Department of Community Medicine, Monitoring of Health Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| |
Collapse
|
3
|
Bohn V, Morata TC, Roggia S, Zucki F, Pouyatos B, Venet T, Krieg E, José MR, de Lacerda ABM. Temporary and Permanent Auditory Effects Associated with Occupational Coexposure to Low Levels of Noise and Solvents. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:9894. [PMID: 36011533 PMCID: PMC9408218 DOI: 10.3390/ijerph19169894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/05/2022] [Accepted: 08/06/2022] [Indexed: 06/15/2023]
Abstract
This study aimed to assess temporary and permanent auditory effects associated with occupational coexposure to low levels of noise and solvents. Cross-sectional study with 25 printing industry workers simultaneously exposed to low noise (<80 dBA TWA) and low levels of solvents. The control group consisted of 29 industry workers without the selected exposures. Participants answered a questionnaire and underwent auditory tests. Auditory fatigue was measured by comparing the acoustic reflex threshold before and after the workday. Workers coexposed to solvents and noise showed significantly worse results in auditory tests in comparison with the participants in the control group. Auditory brainstem response results showed differences in III−V interpeak intervals (p = 0.046 in right ear; p = 0.039 in left ear). Mean dichotic digits scores (exposed = 89.5 ± 13.33; controls = 96.40 ± 4.46) were only different in the left ear (p = 0.054). The comparison of pre and postacoustic reflex testing indicated mean differences (p = 0.032) between the exposed (4.58 ± 6.8) and controls (0 ± 4.62) groups. This study provides evidence of a possible temporary effect (hearing fatigue) at the level of the acoustic reflex of the stapedius muscle. The permanent effects were identified mainly at the level of the high brainstem and in the auditory ability of binaural integration.
Collapse
Affiliation(s)
- Vanessa Bohn
- Post Graduate Program of Communication Disorders, University Tuiuti of Paraná, Curitiba 82010-330, Brazil
| | - Thais C. Morata
- National Institute for Occupational Safety and Health (NIOSH), Cincinnati, OH 45226, USA
| | - Simone Roggia
- Department of Audiology and Speech Therapy, Federal University of Santa Catarina, Florianopolis 88030-300, Brazil
| | - Fernanda Zucki
- Department of Audiology and Speech Therapy, Federal University of Santa Catarina, Florianopolis 88030-300, Brazil
| | - Benoît Pouyatos
- Institut National de Recherche et Sécurité (INRS), 54519 Vandoeuvre-lès-Nancy, France
| | - Thomas Venet
- Institut National de Recherche et Sécurité (INRS), 54519 Vandoeuvre-lès-Nancy, France
| | - Edward Krieg
- National Institute for Occupational Safety and Health (NIOSH), Cincinnati, OH 45226, USA
| | - Maria Renata José
- Post Graduate Program of Communication Disorders, University Tuiuti of Paraná, Curitiba 82010-330, Brazil
| | - Adriana B. M. de Lacerda
- Audiology Department, Speech Language and Audiology School, Medicine Faculty, University of Montréal, Montreal, QC H3C 3J7, Canada
| |
Collapse
|
4
|
Yazici A, Emre Yildirim A, Konduk B, Aytaç İ, Barutçu S. A novel method: can stapedial acoustic reflex have a role in the diagnosis of minimal hepatic encephalopathy? Eur J Gastroenterol Hepatol 2021; 33:717-721. [PMID: 32568804 DOI: 10.1097/meg.0000000000001781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVE Stapedial acoustic reflex is an easily accessible and applicable test which is also valuable for the clinical conditions which affect the various locations of the central nervous system. Searching the diagnostic value of stapedial acoustic reflex at minimal hepatic encephalopathy is the aim of this research. METHODS Diagnosis of minimal hepatic encephalopathy was conducted by mini-mental state and critical flickered frequency tests. Minimal hepatic encephalopathy diagnosed patients were established in the first group. Cirrhosis (without minimal hepatic encephalopathy or overt hepatic encephalopathy) diagnosed patients were created the control group. The stapedial acoustic reflex test was applied for minimal hepatic encephalopathy and the control group by audiologists in a soundproof room. RESULTS In total, 221 patients were screened and 97 patients meet the inclusion criterions. Out of 97 patients, 52 were the minimal hepatic encephalopathy patients and the remaining patients were the control group. Acoustic reflex tests battery includes the evaluation of two pathways called ipsilateral and contralateral. Ipsilateral way test results were found positive in all minimal hepatic encephalopathy patients and 95% positive in the control group. Contralateral acoustic reflex test results were found 36% positive in minimal hepatic encephalopathy patients and 95% positive in the control group, respectively. A comparison of ipsilateral and contralateral acoustic reflex test results was displayed a statistical significance. CONCLUSION Stapedial acoustic reflex test results of cirrhosis patients may cover additional parameters for the diagnosis of minimal hepatic encephalopathy.
Collapse
Affiliation(s)
| | - Abdullah Emre Yildirim
- Gastroenterology, University of Gaziantep Medical Faculty, Department, Gaziantep, Turkey
| | - BuğraTolga Konduk
- Gastroenterology, University of Gaziantep Medical Faculty, Department, Gaziantep, Turkey
| | | | - Sezgin Barutçu
- Gastroenterology, University of Gaziantep Medical Faculty, Department, Gaziantep, Turkey
| |
Collapse
|
5
|
Wathier L, Venet T, Bonfanti E, Nunge H, Cosnier F, Parietti-Winkler C, Campo P, Pouyatos B. Measuring the middle-ear reflex: A quantitative method to assess effects of industrial solvents on central auditory pathways. Neurotoxicology 2019; 74:58-66. [DOI: 10.1016/j.neuro.2019.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 05/15/2019] [Accepted: 05/15/2019] [Indexed: 10/26/2022]
|
6
|
Roggia SM, de França AG, Morata TC, Krieg E, Earl BR. Auditory system dysfunction in Brazilian gasoline station workers. Int J Audiol 2019; 58:484-496. [PMID: 31017499 DOI: 10.1080/14992027.2019.1597286] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Objective: To examine the auditory system of Brazilian gasoline station workers using an extensive audiological test battery. Design: This was a cross-sectional study. The audiological evaluation included a questionnaire, pure-tone audiometry, acoustic immittance tests, transient-evoked otoacoustic emissions (TEOAEs), distortion product otoacoustic emissions (DPOAEs), auditory brainstem response (ABR) and P300 auditory-evoked potentials. Study sample: A total of 77 Brazilian gasoline station workers were evaluated, and their results were compared with those of 36 participants who were not exposed to chemicals or noise at work. The gasoline station employees worked in 18 different gas stations, and the noise area measurements from all gas stations revealed time-weighted averages below 85 dBA. Results: Of the 77 gasoline station workers evaluated, 67.5% had audiometric results within the normal range, but 59.7% reported difficulties in communication in noisy places. Gasoline station workers showed significantly poorer results than non-exposed control participants in one or more conditions of each of the audiological tests used, except P300. Conclusions: The results suggest that the gasoline station workers have both peripheral and central auditory dysfunctions that could be partly explained by their exposure to gasoline.
Collapse
Affiliation(s)
- Simone Mariotti Roggia
- a Department of Audiology and Speech Therapy , Federal University of Santa Catarina , Florianopolis , Brazil
| | | | - Thais C Morata
- c National Institute for Occupational Safety and Heath , Cincinnati , OH , USA
| | - Edward Krieg
- c National Institute for Occupational Safety and Heath , Cincinnati , OH , USA
| | - Brian R Earl
- d Department of Communication Sciences and Disorders , University of Cincinnati , Cincinnati , OH , USA
| |
Collapse
|
7
|
Fuente A, Qiu W, Zhang M, Xie H, Kardous CA, Campo P, Morata TC. Use of the kurtosis statistic in an evaluation of the effects of noise and solvent exposures on the hearing thresholds of workers: An exploratory study. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 143:1704. [PMID: 29604694 PMCID: PMC8588570 DOI: 10.1121/1.5028368] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The aim of this exploratory study was to examine whether the kurtosis metric can contribute to investigations of the effects of combined exposure to noise and solvents on human hearing thresholds. Twenty factory workers exposed to noise and solvents along with 20 workers of similar age exposed only to noise in eastern China were investigated using pure-tone audiometry (1000-8000 Hz). Exposure histories and shift-long noise recording files were obtained for each participant. The data were used in the calculation of the cumulative noise exposure (CNE) and CNE adjusted by the kurtosis metric for each participant. Passive samplers were used to measure solvent concentrations for each worker exposed to solvents over the full work shift. Results showed an interaction between noise exposure and solvents for the hearing threshold at 6000 Hz. This effect was observed only when the CNE level was adjusted by the kurtosis metric.
Collapse
Affiliation(s)
- Adrian Fuente
- École d'orthophonie et d'audiologie, Faculté de médecine, Université de Montréal and Centre de recherche de l'Institut universitaire de gériatrie de Montréal, Montréal, Canada
| | - Wei Qiu
- Auditory Research Laboratory, State University of New York, Plattsburgh, New York 12901, USA
| | - Meibian Zhang
- Institute of Environmental and Occupational Health, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Hongwei Xie
- Institute of Environmental and Occupational Health, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Chucri A Kardous
- National Institute for Occupational Safety and Health, Cincinnati, Ohio 45226, USA
| | - Pierre Campo
- Institut National de Recherche et de Sécurité, Vandœuvre-les-Nancy, France
| | - Thais C Morata
- National Institute for Occupational Safety and Health, Cincinnati, Ohio 45226, USA
| |
Collapse
|
8
|
Effects of thiocolchicoside, a commonly used myorelaxant, on the acoustic reflex. The Journal of Laryngology & Otology 2017; 131:497-500. [PMID: 28249630 DOI: 10.1017/s0022215117000512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To determine whether thiocolchicoside, a commonly used myorelaxant, may impair the acoustic reflex. METHODS Forty-two patients scheduled to receive thiocolchicoside treatment for different reasons were enrolled in the study. Acoustic reflex thresholds at 500, 1000, 2000 and 4000 Hz were determined and analysed statistically pre-treatment and on the 5th day of treatment. RESULTS Increases were observed in the mean acoustic reflex thresholds on the 5th day of treatment compared to pre-treatment, at all frequencies, except right contralateral thresholds at 500 and 2000 Hz. These increases were statistically significant for right ipsilateral thresholds at 2000 and 4000 Hz, left ipsilateral thresholds at 500, 1000, 2000 and 4000 Hz, and left contralateral thresholds at 2000 and 4000 Hz (p ≤ 0.05), but not at other frequencies (p > 0.05). CONCLUSION Muscle relaxant drugs, especially those affecting the central nervous system, may weaken the stapedial muscle so that the ability of noise to cause acoustic trauma may become evident. For this reason, physicians should advise their patients to avoid loud noises when muscle relaxant therapy is prescribed.
Collapse
|
9
|
Carbon disulfide potentiates the effects of impulse noise on the organ of Corti. Neurotoxicology 2017; 59:79-87. [DOI: 10.1016/j.neuro.2017.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/07/2017] [Accepted: 02/07/2017] [Indexed: 01/05/2023]
|
10
|
Wathier L, Venet T, Thomas A, Nunge H, Bonfanti E, Cosnier F, Parietti-Winkler C, Campo P, Tsan P, Bouguet-Bonnet S, Gansmüller A. Membrane fluidity does not explain how solvents act on the middle-ear reflex. Neurotoxicology 2016; 57:13-21. [PMID: 27565678 DOI: 10.1016/j.neuro.2016.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 07/26/2016] [Accepted: 08/03/2016] [Indexed: 10/21/2022]
Abstract
Some volatile aromatic solvents have similar or opposite effects to anesthetics in the central nervous system. Like for anesthetics, the mechanisms of action involved are currently the subject of debate. This paper presents an in vivo study to determine whether direct binding or effects on membrane fluidity best explain how solvents counterbalance anesthesia's depression of the middle-ear reflex (MER). Rats were anesthetized with a mixture of ketamine and xylazine while also exposed to solvent vapors (toluene, ethylbenzene, or one of the three xylene isomers) and the amplitude of their MER was monitored. The depth of anesthesia was standardized based on the magnitude of the contraction of the muscles involved in the MER, determined by measuring cubic distortion product oto-acoustic emissions (DPOAEs) while triggering the bilateral reflex with contralateral acoustic stimulation. The effects of the aromatic solvents were quantified based on variations in the amplitude of the DPOAEs. The amplitude of the alteration to the MER measured in anesthetized rats did not correlate with solvent lipophilocity (as indicated by logKow values). Results obtained with the three xylene isomers indicated that the positions of two methyl groups around the benzene ring played a determinant role in solvent/neuronal cell interaction. Additionally, Solid-state Nuclear Magnetic Resonance (NMR) spectra for brain microsomes confirmed that brain lipid fluidity was unaffected by solvent exposure, even after three days (6h/day) at an extremely high concentration (3000ppm). Therefore, aromatic solvents appear to act directly on the neuroreceptors involved in the acoustic reflex circuit, rather than on membrane fluidity. The affinity of this interaction is determined by stereospecific parameters rather than lipophilocity.
Collapse
Affiliation(s)
- Ludivine Wathier
- Institut National de Recherche et de Sécurité, Rue du Morvan, F-54519 Vandoeuvre-les-Nancy, France
| | - Thomas Venet
- Institut National de Recherche et de Sécurité, Rue du Morvan, F-54519 Vandoeuvre-les-Nancy, France
| | - Aurélie Thomas
- Institut National de Recherche et de Sécurité, Rue du Morvan, F-54519 Vandoeuvre-les-Nancy, France
| | - Hervé Nunge
- Institut National de Recherche et de Sécurité, Rue du Morvan, F-54519 Vandoeuvre-les-Nancy, France
| | - Elodie Bonfanti
- Institut National de Recherche et de Sécurité, Rue du Morvan, F-54519 Vandoeuvre-les-Nancy, France
| | - Frédéric Cosnier
- Institut National de Recherche et de Sécurité, Rue du Morvan, F-54519 Vandoeuvre-les-Nancy, France
| | | | - Pierre Campo
- Institut National de Recherche et de Sécurité, Rue du Morvan, F-54519 Vandoeuvre-les-Nancy, France.
| | - Pascale Tsan
- Université de Lorraine, CRM2, UMR 7036, Vandoeuvre-les-Nancy, F-54506, France; CNRS, CRM2, UMR 7036, Vandoeuvre-les-Nancy, F-54506, France
| | - Sabine Bouguet-Bonnet
- Université de Lorraine, CRM2, UMR 7036, Vandoeuvre-les-Nancy, F-54506, France; CNRS, CRM2, UMR 7036, Vandoeuvre-les-Nancy, F-54506, France
| | - Axel Gansmüller
- Université de Lorraine, CRM2, UMR 7036, Vandoeuvre-les-Nancy, F-54506, France; CNRS, CRM2, UMR 7036, Vandoeuvre-les-Nancy, F-54506, France
| |
Collapse
|
11
|
Venet T, Campo P, Thomas A, Cour C, Rieger B, Cosnier F. The tonotopicity of styrene-induced hearing loss depends on the associated noise spectrum. Neurotoxicol Teratol 2015; 48:56-63. [DOI: 10.1016/j.ntt.2015.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 02/09/2015] [Accepted: 02/09/2015] [Indexed: 11/25/2022]
|
12
|
Campo P, Venet T, Thomas A, Cour C, Brochard C, Cosnier F. Neuropharmacological and cochleotoxic effects of styrene. Consequences on noise exposures. Neurotoxicol Teratol 2014; 44:113-20. [DOI: 10.1016/j.ntt.2014.05.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/21/2014] [Accepted: 05/28/2014] [Indexed: 10/25/2022]
|
13
|
Venet T, Campo P, Rumeau C, Thomas A, Parietti-Winkler C. One-day measurement to assess the auditory risks encountered by noise-exposed workers. Int J Audiol 2014; 53:737-44. [DOI: 10.3109/14992027.2014.913210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
14
|
|
15
|
Abstract
OBJETIVO: avaliar os limiares auditivos nas frequências convencionais e altas frequências, e ainda a integridade do arco reflexo, em frentistas. MÉTODO: foram avaliados frentistas de três postos de gasolina da cidade de Santa Maria/RS. Após adequação aos critérios de inclusão, a amostra ficou composta por 24 frentistas expostos a combustíveis, 21 do gênero masculino e três do gênero feminino, com faixa etária entre 20 e 40 anos. Os exames utilizados foram audiometria tonal liminar, audiometria de altas frequências e imitanciometria. O tempo de exposição variou de um a 17 anos. O grupo controle foi composto por 24 sujeitos não expostos a qualquer agente nocivo à audição. RESULTADOS: a média dos limiares da audiometria tonal liminar e da audiometria de altas frequências foi superior no grupo estudo em todas as frequências testadas. Verificou-se diferença de limiar estatisticamente significante nas frequências de 0,5 (p=0,004), 2 (p=0,001) e 3 kHz (p=0,025), e nas frequências de 9 (p=0,007) e 10 kHz (p=0,026). Os limiares das frequências de 12,5 e 14 kHz não diferiram estatisticamente (p>0,05). Em 16, 18 e 20 kHz foi observada maior ausência de respostas no grupo estudo (p>0,05). Também se observou maior ausência de reflexos acústicos (ipsi e contralateral) no grupo estudo, na orelha direita. Na orelha esquerda, não houve diferença entre os grupos, para a ocorrência do reflexo ipsilateral. A ausência de reflexo contralateral foi maior no grupo estudo em todas as frequências testadas. CONCLUSÃO: frentistas com limiares auditivos normais podem apresentar alterações cocleares e centrais.
Collapse
|
16
|
Campo P, Venet T, Thomas A, Cour C, Castel B, Nunge H, Cosnier F. Inhaled toluene can modulate the effects of anesthetics on the middle-ear acoustic reflex. Neurotoxicol Teratol 2012. [PMID: 23183362 DOI: 10.1016/j.ntt.2012.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Toluene (Tol) is an organic solvent widely used in the industry. It is also abused as an inhaled solvent, and can have deleterious effects on hearing. Recently, it was demonstrated that Tol has both anticholinergic and antiglutamatergic effects, and that it also inhibits voltage-dependent Ca(2+) channels. This paper describes a study of the effects of inhaled Tol on rats anesthetized with isoflurane, pentobarbital, or a mixture of ketamine/xylazine. Hearing was tested using distortion product oto-acoustic emissions (DPOAEs) associated with a contralateral noise to evaluate contraction of the middle-ear muscles. This allowed us to assess the interactions between the effects of Tol and anesthesia on the central nervous system (CNS). Although both anesthetics and Tol are known to inhibit the middle-ear acoustic reflex, our data indicated that inhaled Tol counterbalances the effects of anesthetic in a dose-dependent manner. In other terms, Tol can increase the amplitude of the middle-ear reflex in anesthetized rats, whatever the nature of the anesthetic used. This indicates that inhaling Tol (a Ca(2+)-channel-blocking drug) modifies the potency of anesthesia, and thereby the amplitude of the middle-ear reflex.
Collapse
Affiliation(s)
- Pierre Campo
- Institut National de Recherche et de Sécurité, Vandœuvre Cedex, France.
| | | | | | | | | | | | | |
Collapse
|
17
|
Campo P, Venet T, Rumeau C, Thomas A, Rieger B, Cour C, Cosnier F, Parietti-Winkler C. Impact of noise or styrene exposure on the kinetics of presbycusis. Hear Res 2011; 280:122-32. [PMID: 21616132 DOI: 10.1016/j.heares.2011.04.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 04/27/2011] [Accepted: 04/28/2011] [Indexed: 10/18/2022]
Abstract
Presbycusis, or age-related hearing loss is a growing problem as the general population ages. In this longitudinal study, the influence of noise or styrene exposure on presbycusis was investigated in Brown Norway rats. Animals were exposed at 6 months of age, either to a band noise centered at 8 kHz at a Lex,8h = 85 dB (86.2 dB SPL for 6 h), or to 300 ppm of styrene for 6 h per day, five days per week, for four weeks. Cubic distortion product otoacoustic emissions (2f1-f2 DPOAEs) were used to test the capacity of the auditory receptor over the lifespan of the animals. 2f1-f2DPOAE measurements are easy to implement and efficiently track the age-related deterioration of mid- and high-frequencies. They are good indicators of temporary auditory threshold shift, especially with a level of primaries close to 60 dB SPL. Post-exposure hearing defects are best identified using moderate, rather than high, levels of primaries. Like many aging humans, aging rats lose sensitivity to high-frequencies faster than to medium-frequencies. Although the results obtained with the styrene exposure were not entirely conclusive, histopathological data showed the presbycusis process to be enhanced. Noise-exposed rats exhibit a loss of spiral ganglion cells from 12 months and a 7 dB drop in 2f1-f2DPOAEs at 24 months, indicating that even moderate-intensity noise can accelerate the presbycusis process. Even though the results obtained with the styrene exposure are less conclusive, the histopathological data show an enhancement of the presbycusis process.
Collapse
Affiliation(s)
- Pierre Campo
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, 54519 Vandœuvre Cédex, France.
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Rumeau C, Campo P, Venet T, Thomas A, Cour C, Parietti-Winkler C. Toluene effect on the olivocochlear reflex. Toxicol Sci 2011; 121:140-5. [PMID: 21292641 DOI: 10.1093/toxsci/kfr025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Animal studies have shown that toluene can cause hearing loss and can exacerbate the effects of noise by inhibiting the middle ear acoustic reflex. In this investigation, carried out in Long-Evans rats, the tensor tympani tendon was cutoff and the stapedius muscle was electrocoagulated in one or both middle ears. Rat hearing was evaluated by measuring cubic distortion otoacoustic emissions (2f1-f2; f1 = 8000 Hz; f2 = 9600 Hz; f1/f2 = 1.2) prior to, during, and after activation of the olivocochlear (OC) reflex. A band noise centered at 4 kHz was used as suppressor noise. It was delivered contralaterally to decrease 2f1-f2 amplitude. The strength of the inner ear acoustic reflex was tested by increasing contralateral noise intensity, and toluene injected into the carotid artery was used to study physiological efficacy. Results showed that the protective effect of the OC reflex is intensity dependent. In addition, the OC reflex was found to be less sensitive to toluene than the middle ear acoustic reflex. This may be because the efferent neurons involved in inner ear and middle ear reflexes are located differently. In conclusion, the synergistic effects on hearing of co-exposure to noise and aromatic solvents are because of solvents depressing the central nuclei, which mainly drive the middle ear acoustic reflex.
Collapse
Affiliation(s)
- Cécile Rumeau
- Polluants et Santé Department, Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, 54519 Vandœuvre Cédex, France
| | | | | | | | | | | |
Collapse
|