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Venet T, Thomas A, Merlen L, Boucard S, Wathier L, Martin Remy A, Pouyatos B. Parameters influencing auditory fatigue among professionals working in the amplified music sector: noise exposure and individual factors. Int J Audiol 2023:1-9. [PMID: 37622173 DOI: 10.1080/14992027.2023.2240012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 07/13/2023] [Accepted: 07/18/2023] [Indexed: 08/26/2023]
Abstract
OBJECTIVE Hearing disorders are common among music professionals, as they are frequently exposed to sound levels exceeding 100 dB(A). By assessing auditory fatigue, situations that are deleterious for hearing could be identified, allowing the deployment of preventive measures before permanent impairment occurs. However, little is known about the factors contributing to auditory fatigue. The objective is to determine the exposure parameters most influencing auditory fatigue during occupational exposure to amplified music. DESIGN Auditory fatigue was defined as variations of both pure tone auditory (ΔPTA) and efferent reflex thresholds (ΔER) during the workday. Noise exposure was monitored and information on the volunteers was gathered using a questionnaire. STUDY SAMPLE The population consisted of 43 adult volunteers exposed to amplified music (sound, light or stage technicians, security agents, barmen) and 24 unexposed administrative agents. RESULTS ΔPTA and ΔER were positively correlated with the energy of noise exposure and its stability over time, i.e a steady noise tends to create more auditory fatigue. CONCLUSION In addition to a global decrease of music levels and a systematic use of hearing protection, our results advocate for the provision of quiet periods within noise exposures as they reduce auditory fatigue accumulation and long-term risks for hearing.
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Affiliation(s)
- Thomas Venet
- Institut National de Recherche et de Sécurité, Vandœuvre-lès-Nancy, France
- DevAH EA 3450 - Développement, Adaptation et Handicap, Régulations cardio-respiratoires et de la motricité-Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Aurélie Thomas
- Institut National de Recherche et de Sécurité, Vandœuvre-lès-Nancy, France
| | - Lise Merlen
- Institut National de Recherche et de Sécurité, Vandœuvre-lès-Nancy, France
| | - Stéphane Boucard
- Institut National de Recherche et de Sécurité, Vandœuvre-lès-Nancy, France
| | - Ludivine Wathier
- Institut National de Recherche et de Sécurité, Vandœuvre-lès-Nancy, France
| | | | - Benoit Pouyatos
- Institut National de Recherche et de Sécurité, Vandœuvre-lès-Nancy, France
- DevAH EA 3450 - Développement, Adaptation et Handicap, Régulations cardio-respiratoires et de la motricité-Université de Lorraine, Vandœuvre-lès-Nancy, France
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Tallandier V, Merlen L, Chalansonnet M, Boucard S, Thomas A, Venet T, Pouyatos B. Three-dimensional cultured ampullae from rats as a screening tool for vestibulotoxicity: Proof of concept using styrene. Toxicology 2023; 495:153600. [PMID: 37516305 DOI: 10.1016/j.tox.2023.153600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Numerous ototoxic drugs, such as some antibiotics and chemotherapeutics, are both cochleotoxic and vestibulotoxic (causing hearing loss and vestibular disorders). However, the impact of some industrial cochleotoxic compounds on the vestibular receptor, if any, remains unknown. As in vivo studies are long and expensive, there is considerable need for predictive and cost-effective in vitro models to test ototoxicity. Here, we present an organotypic model of cultured ampullae harvested from rat neonates. When cultured in a gelatinous matrix, ampulla explants form an enclosed compartment that progressively fills with a high-potassium (K+) endolymph-like fluid. Morphological analyses confirmed the presence of a number of cell types, sensory epithelium, secretory cells, and canalar cells. Treatments with inhibitors of potassium transporters demonstrated that the potassium homeostasis mechanisms were functional. To assess the potential of this model to reveal the toxic effects of chemicals, explants were exposed for either 2 or 72 h to styrene at a range of concentrations (0.5-1 mM). In the 2-h exposure condition, K+ concentration was significantly reduced, but ATP levels remained stable, and no histological damage was visible. After 72 h exposure, variations in K+ concentration were associated with histological damage and decreased ATP levels. This in vitro 3D neonatal rat ampulla model therefore represents a reliable and rapid means to assess the toxic properties of industrial compounds on this vestibular tissue, and can be used to investigate the specific underlying mechanisms.
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Affiliation(s)
- V Tallandier
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France; DevAH EA 3450 - Développement, Adaptation et Handicap. Régulations cardio-respiratoires et de la motricité-Université de Lorraine, F-54500 Vandœuvre, France
| | - L Merlen
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France
| | - M Chalansonnet
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France.
| | - S Boucard
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France
| | - A Thomas
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France
| | - T Venet
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France; DevAH EA 3450 - Développement, Adaptation et Handicap. Régulations cardio-respiratoires et de la motricité-Université de Lorraine, F-54500 Vandœuvre, France
| | - B Pouyatos
- French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), Toxicology and Biomonitoring Division, Vandoeuvre les Nancy, France; DevAH EA 3450 - Développement, Adaptation et Handicap. Régulations cardio-respiratoires et de la motricité-Université de Lorraine, F-54500 Vandœuvre, France
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Tallandier V, Merlen L, Boucard S, Thomas A, Venet T, Chalansonnet M, Gauchard G, Campo P, Pouyatos B. Styrene alters potassium endolymphatic concentration in a model of cultured utricle explants. Toxicol In Vitro 2020; 67:104915. [PMID: 32540163 DOI: 10.1016/j.tiv.2020.104915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 06/02/2020] [Accepted: 06/11/2020] [Indexed: 12/23/2022]
Abstract
Despite well-documented neurotoxic and ototoxic properties, styrene remains commonly used in industry. Its effects on the cochlea have been extensively studied in animals, and epidemiological and animal evidence indicates an impact on balance. However, its influence on the peripheral vestibular receptor has yet to be investigated. Here, we assessed the vestibulotoxicity of styrene using an in vitro model, consisting of three-dimensional cultured newborn rat utricles filled with a high‑potassium (K+) endolymph-like fluid, called "cysts". K+ entry in the cyst ("influx") and its exit ("efflux") are controlled by secretory cells and hair cells, respectively. The vestibular epithelium's functionality is thus linked to K+ concentration, measured using a microelectrode. Known inhibitors of K+ efflux and influx validated the model. Cysts were subsequently exposed to styrene (0.25; 0.5; 0.75 and 1 mM) for 2 h or 72 h. The decrease in K+ concentration measured after both exposure durations was dose-dependent, and significant from 0.75 mM styrene. Vacuoles were visible in the cytoplasm of epithelial cells from 0.5 mM after 2 h and from 0.25 mM after 72 h. The results presented here are the first evidence that styrene may deregulate K+ homeostasis in the endolymphatic space, thereby altering the functionality of the vestibular receptor.
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Affiliation(s)
- V Tallandier
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre, Cedex, France; DevAH EA 3450 - Développement, Adaptation et Handicap, Régulations cardio-respiratoires et de la motricité-Université de Lorraine, F-54500 Vandœuvre, France
| | - L Merlen
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre, Cedex, France
| | - S Boucard
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre, Cedex, France
| | - A Thomas
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre, Cedex, France
| | - T Venet
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre, Cedex, France; DevAH EA 3450 - Développement, Adaptation et Handicap, Régulations cardio-respiratoires et de la motricité-Université de Lorraine, F-54500 Vandœuvre, France
| | - M Chalansonnet
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre, Cedex, France.
| | - G Gauchard
- DevAH EA 3450 - Développement, Adaptation et Handicap, Régulations cardio-respiratoires et de la motricité-Université de Lorraine, F-54500 Vandœuvre, France
| | - P Campo
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre, Cedex, France; DevAH EA 3450 - Développement, Adaptation et Handicap, Régulations cardio-respiratoires et de la motricité-Université de Lorraine, F-54500 Vandœuvre, France
| | - B Pouyatos
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre, Cedex, France
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Chalansonnet M, Carreres-Pons M, Venet T, Thomas A, Merlen L, Boucard S, Cosnier F, Nunge H, Bonfanti E, Llorens J, Campo P, Pouyatos B. Effects of co-exposure to CS 2 and noise on hearing and balance in rats: continuous versus intermittent CS 2 exposures. J Occup Med Toxicol 2020; 15:9. [PMID: 32426022 PMCID: PMC7216478 DOI: 10.1186/s12995-020-00260-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 04/15/2020] [Indexed: 11/10/2022] Open
Abstract
Background Carbon disulfide (CS2) exacerbates the effect of noise on hearing, and disrupts the vestibular system. The goal of this study was to determine whether these effects are also observed with intermittent CS2 exposure. Methods Rats were exposed for 4 weeks (5 days/week, 6 h/day) to a band noise at 106 dB SPL either alone or combined with continuous (63 ppm or 250 ppm) or intermittent (15 min/h or 2 × 15 min/h at 250 ppm) CS2. Hearing function was assessed by measuring distortion product otoacoustic emissions (DPOAEs); balance was monitored based on the vestibulo-ocular reflex (VOR). Functional measurements were performed before, at the end of exposure and 4 weeks later. Histological analyses of the inner ear were also performed following exposure and after the 4-week recovery period. Results The results obtained here confirmed that CS2 exposure exerts two differential temporary effects on hearing: (1) it attenuates the noise-induced DPOAE decrease below 6 kHz probably through action on the middle ear reflex when exposure lasts 15 min per hour, and (2) continuous exposure to 250 ppm for 6 h extends the frequency range affected by noise up to 9.6 kHz (instead of 6 kHz with noise alone). With regard to balance, the VOR was reversibly disrupted at the two highest doses of CS2 (2 × 15 min/h and continuous 250 ppm). No morphological alterations to the inner ear were observed. Conclusion These results reveal that short periods of CS2 exposure can alter the sensitivity of the cochlea to noise at a dose equivalent to only 10 times the short-term occupational limit value, and intermittent exposure to CS2 (2 × 15 min/h) can alter the function of the vestibular system.
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Affiliation(s)
- Monique Chalansonnet
- 1Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, Cedex, 54519 Vandœuvre, France
| | - Maria Carreres-Pons
- 1Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, Cedex, 54519 Vandœuvre, France.,2Departament de Ciències Fisiològiques and Institute of Neurosciences, Universitat de Barcelona, 08907 L'Hospitalet de Llobregat, Catalonia Spain
| | - Thomas Venet
- 1Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, Cedex, 54519 Vandœuvre, France
| | - Aurélie Thomas
- 1Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, Cedex, 54519 Vandœuvre, France
| | - Lise Merlen
- 1Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, Cedex, 54519 Vandœuvre, France
| | - Stéphane Boucard
- 1Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, Cedex, 54519 Vandœuvre, France
| | - Frédéric Cosnier
- 1Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, Cedex, 54519 Vandœuvre, France
| | - Hervé Nunge
- 1Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, Cedex, 54519 Vandœuvre, France
| | - Elodie Bonfanti
- 1Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, Cedex, 54519 Vandœuvre, France
| | - Jordi Llorens
- 2Departament de Ciències Fisiològiques and Institute of Neurosciences, Universitat de Barcelona, 08907 L'Hospitalet de Llobregat, Catalonia Spain.,3Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), 08907 L'Hospitalet de Llobregat, Catalonia Spain
| | - Pierre Campo
- 1Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, Cedex, 54519 Vandœuvre, France.,4DevAH EA 3450 - Développement, Adaptation et Handicap, Régulations cardio-respiratoires et de la motricité-Université de Lorraine, 54500 Vandœuvre, France
| | - Benoît Pouyatos
- 1Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, Cedex, 54519 Vandœuvre, France
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Chalansonnet M, Carreres-Pons M, Venet T, Thomas A, Merlen L, Seidel C, Cosnier F, Nunge H, Pouyatos B, Llorens J, Campo P. Combined exposure to carbon disulfide and low-frequency noise reversibly affects vestibular function. Neurotoxicology 2018; 67:270-278. [PMID: 29928918 DOI: 10.1016/j.neuro.2018.06.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 06/01/2018] [Accepted: 06/15/2018] [Indexed: 01/22/2023]
Abstract
Chronic occupational exposure to carbon disulfide (CS2) has debilitating motor and sensory effects in humans, which can increase the risk of falls. Although no mention of vestibulotoxic effects is contained in the literature, epidemiological and experimental data suggest that CS2 could cause low-frequency hearing loss when associated with noise exposure. Low-frequency noise might also perturb the peripheral balance receptor through an as-yet unclear mechanism. Here, we studied how exposure to a low-frequency noise combined with 250-ppm CS2 affected balance in rats. Vestibular function was tested based on post-rotary nystagmus recorded by a video-oculography system. These measurements were completed by behavioral tests and analysis of the cerebellum to measure expression levels for gene expression associated with neurotoxicity. Assays were performed prior to and following a 4-week exposure, and again after a 4-week recovery period. Functional measurements were completed by histological analyses of the peripheral organs.Nystagmus was unaltered by exposure to noise alone, while CS2 alone caused a moderate 19% decrease of the saccade number. In contrast, coexposure to 250-ppm CS2 and low-frequency noise decreased both saccade number and duration by 33% and 34%, respectively. After four weeks, recovery was only partial but measures were not significantly different from pre-exposure values. Real-time quantitative polymerase chain reaction (RT-qPCR) analysis of cerebellar tissue revealed a slight but significant modification in expression levels for two genes linked to neurotoxicity in CS2-exposed animals. However, neither histopathological changes to the peripheral receptor nor behavioral differences were observed. Based on all these results, we propose that the effects of CS2 were due to reversible neurochemical disturbance of the efferent pathways managing post-rotatory nystagmus. Because the nervous structures involving the vestibular function appear particularly sensitive to CS2, post-rotary nystagmus could be used as an early, non-invasive measurement to diagnose CS2 intoxication as part of an occupational conservation program.
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Affiliation(s)
- Monique Chalansonnet
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre Cedex, France.
| | - Maria Carreres-Pons
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre Cedex, France; Departament de Ciències Fisiològiques and Institute of Neurosciences, Universitat de Barcelona, 08907 L'Hospitalet de Llobregat, Catalonia, Spain
| | - Thomas Venet
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre Cedex, France
| | - Aurélie Thomas
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre Cedex, France
| | - Lise Merlen
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre Cedex, France
| | - Carole Seidel
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre Cedex, France
| | - Frédéric Cosnier
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre Cedex, France
| | - Hervé Nunge
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre Cedex, France
| | - Benoît Pouyatos
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre Cedex, France
| | - Jordi Llorens
- Departament de Ciències Fisiològiques and Institute of Neurosciences, Universitat de Barcelona, 08907 L'Hospitalet de Llobregat, Catalonia, Spain; Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), 08907 L'Hospitalet de Llobregat, Catalonia, Spain
| | - Pierre Campo
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519 Vandœuvre Cedex, France; DevAH EA 3450 - Développement, Adaptation et Handicap, Régulations cardio-respiratoires et de la motricité-Université de Lorraine, F-54500 Vandœuvre, France
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Chalansonnet M, Carabin N, Boucard S, Merlen L, Melczer M, Antoine G, Devoy J, Remy A, Gagnaire F. Study of potential transfer of aluminum to the brain via the olfactory pathway. Toxicol Lett 2017; 283:77-85. [PMID: 29180288 DOI: 10.1016/j.toxlet.2017.11.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 11/22/2017] [Accepted: 11/23/2017] [Indexed: 11/17/2022]
Abstract
Many employees in the aluminum industry are exposed to a range of aluminum compounds by inhalation, and the presence of ultrafine particles in the workplace has become a concern to occupational health professionals. Some metal salts and metal oxides have been shown to enter the brain through the olfactory route, bypassing the blood-brain barrier, but few studies have examined whether aluminum compounds also use this pathway. In this context, we sought to determine whether aluminum was found in rat olfactory bulbs and whether its transfer depended on physicochemical characteristics such as solubility and granulometry. Aluminum salts (chloride and fluoride) and various nanometric aluminum oxides (13nm, 20nm and 40-50nm) were administered to rats by intranasal instillation through one nostril (10μg Al/30μL for 10days). Olfactory bulbs (ipsilateral and contralateral relative to instilled nostril) were harvested and the aluminum content was determined by graphite furnace atomic absorption spectrometry after tissue mineralization. Some transfer of aluminum salts to the central nervous system via the olfactory route was observed, with the more soluble aluminum chloride being transferred at higher levels than aluminum fluoride. No cerebral translocation of any of the aluminas studied was detected.
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Affiliation(s)
- Monique Chalansonnet
- INRS, Département Toxicologie et Biométrologie, Rue du Morvan, CS 60027, F-54519, Vandœuvre-lès-Nancy, France.
| | - Nathalie Carabin
- INRS, Département Toxicologie et Biométrologie, Rue du Morvan, CS 60027, F-54519, Vandœuvre-lès-Nancy, France
| | - Stéphane Boucard
- INRS, Département Toxicologie et Biométrologie, Rue du Morvan, CS 60027, F-54519, Vandœuvre-lès-Nancy, France
| | - Lise Merlen
- INRS, Département Toxicologie et Biométrologie, Rue du Morvan, CS 60027, F-54519, Vandœuvre-lès-Nancy, France
| | - Mathieu Melczer
- INRS, Département Toxicologie et Biométrologie, Rue du Morvan, CS 60027, F-54519, Vandœuvre-lès-Nancy, France
| | - Guillaume Antoine
- INRS, Département Toxicologie et Biométrologie, Rue du Morvan, CS 60027, F-54519, Vandœuvre-lès-Nancy, France
| | - Jérôme Devoy
- INRS, Département Toxicologie et Biométrologie, Rue du Morvan, CS 60027, F-54519, Vandœuvre-lès-Nancy, France
| | - Aurélie Remy
- INRS, Département Toxicologie et Biométrologie, Rue du Morvan, CS 60027, F-54519, Vandœuvre-lès-Nancy, France
| | - François Gagnaire
- INRS, Département Toxicologie et Biométrologie, Rue du Morvan, CS 60027, F-54519, Vandœuvre-lès-Nancy, France
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Venet T, Carreres-Pons M, Chalansonnet M, Thomas A, Merlen L, Nunge H, Bonfanti E, Cosnier F, Llorens J, Campo P. Continuous exposure to low-frequency noise and carbon disulfide: Combined effects on hearing. Neurotoxicology 2017; 62:151-161. [PMID: 28655499 DOI: 10.1016/j.neuro.2017.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 06/22/2017] [Accepted: 06/22/2017] [Indexed: 10/19/2022]
Abstract
Carbon disulfide (CS2) is used in industry; it has been shown to have neurotoxic effects, causing central and distal axonopathies.However, it is not considered cochleotoxic as it does not affect hair cells in the organ of Corti, and the only auditory effects reported in the literature were confined to the low-frequency region. No reports on the effects of combined exposure to low-frequency noise and CS2 have been published to date. This article focuses on the effects on rat hearing of combined exposure to noise with increasing concentrations of CS2 (0, 63,250, and 500ppm, 6h per day, 5 days per week, for 4 weeks). The noise used was a low-frequency noise ranging from 0.5 to 2kHz at an intensity of 106dB SPL. Auditory function was tested using distortion product oto-acoustic emissions, which mainly reflects the cochlear performances. Exposure to noise alone caused an auditory deficit in a frequency area ranging from 3.6 to 6 kHz. The damaged area was approximately one octave (6kHz) above the highest frequency of the exposure noise (2.8kHz); it was a little wider than expected based on the noise spectrum.Consequently, since maximum hearing sensitivity is located around 8kHz in rats, low-frequency noise exposure can affect the cochlear regions detecting mid-range frequencies. Co-exposure to CS2 (250-ppm and over) and noise increased the extent of the damaged frequency window since a significant auditory deficit was measured at 9.6kHz in these conditions.Moreover, the significance at 9.6kHz increased with the solvent concentrations. Histological data showed that neither hair cells nor ganglion cells were damaged by CS2. This discrepancy between functional and histological data is discussed. Like most aromatic solvents, carbon disulfide should be considered as a key parameter in hearing conservation régulations.
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Affiliation(s)
- Thomas Venet
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519, Vandœuvre Cedex. France.
| | - Maria Carreres-Pons
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519, Vandœuvre Cedex. France; Departament de Ciències Fisiològiques and Institute of Neurosciences, Universitat de Barcelona, 08907 L'Hospitalet de Llobregat, Catalonia, Spain
| | - Monique Chalansonnet
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519, Vandœuvre Cedex. France
| | - Aurélie Thomas
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519, Vandœuvre Cedex. France
| | - Lise Merlen
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519, Vandœuvre Cedex. France
| | - Hervé Nunge
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519, Vandœuvre Cedex. France
| | - Elodie Bonfanti
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519, Vandœuvre Cedex. France
| | - Frédéric Cosnier
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519, Vandœuvre Cedex. France
| | - Jordi Llorens
- Departament de Ciències Fisiològiques and Institute of Neurosciences, Universitat de Barcelona, 08907 L'Hospitalet de Llobregat, Catalonia, Spain; Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), 08907 L'Hospitalet de Llobregat, Catalonia, Spain
| | - Pierre Campo
- Institut National de Recherche et de Sécurité, Rue du Morvan, CS 60027, F-54519, Vandœuvre Cedex. France; DevAH EA 3450 - Développement, Adaptation et Handicap, Régulations cardio-respiratoires et de la motricité-Université de Lorraine, F-54500 Vandœuvre, France
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