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Herb M. NADPH Oxidase 3: Beyond the Inner Ear. Antioxidants (Basel) 2024; 13:219. [PMID: 38397817 PMCID: PMC10886416 DOI: 10.3390/antiox13020219] [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: 01/13/2024] [Revised: 02/02/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Reactive oxygen species (ROS) were formerly known as mere byproducts of metabolism with damaging effects on cellular structures. The discovery and description of NADPH oxidases (Nox) as a whole enzyme family that only produce this harmful group of molecules was surprising. After intensive research, seven Nox isoforms were discovered, described and extensively studied. Among them, the NADPH oxidase 3 is the perhaps most underrated Nox isoform, since it was firstly discovered in the inner ear. This stigma of Nox3 as "being only expressed in the inner ear" was also used by me several times. Therefore, the question arose whether this sentence is still valid or even usable. To this end, this review solely focuses on Nox3 and summarizes its discovery, the structural components, the activating and regulating factors, the expression in cells, tissues and organs, as well as the beneficial and detrimental effects of Nox3-mediated ROS production on body functions. Furthermore, the involvement of Nox3-derived ROS in diseases progression and, accordingly, as a potential target for disease treatment, will be discussed.
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Affiliation(s)
- Marc Herb
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine, University Hospital Cologne, University of Cologne, 50935 Cologne, Germany;
- German Centre for Infection Research, Partner Site Bonn-Cologne, 50931 Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Aging-Associated Diseases (CECAD), 50931 Cologne, Germany
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2
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Zhou Y, Fang C, Yuan L, Guo M, Xu X, Shao A, Zhang A, Zhou D. Redox homeostasis dysregulation in noise-induced hearing loss: oxidative stress and antioxidant treatment. J Otolaryngol Head Neck Surg 2023; 52:78. [PMID: 38082455 PMCID: PMC10714662 DOI: 10.1186/s40463-023-00686-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 12/04/2023] [Indexed: 12/18/2023] Open
Abstract
Noise exposure is an important cause of acquired hearing loss. Studies have found that noise exposure causes dysregulated redox homeostasis in cochlear tissue, which has been recognized as a signature feature of hearing loss. Oxidative stress plays a pivotal role in many diseases via very complex and diverse mechanisms and targets. Reactive oxygen species are products of oxidative stress that exert toxic effects on a variety of physiological activities and are considered significant in noise-induced hearing loss (NIHL). Endogenous cellular antioxidants can directly or indirectly counteract oxidative stress and regulate intracellular redox homeostasis, and exogenous antioxidants can complement and enhance this effect. Therefore, antioxidant therapy is considered a promising direction for NIHL treatment. However, drug experiments have been limited to animal models of NIHL, and these experiments and related observations are difficult to translate in humans; therefore, the mechanisms and true effects of these drugs need to be further analyzed. This review outlines the effects of oxidative stress in NIHL and discusses the main mechanisms and strategies of antioxidant treatment for NIHL.
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Affiliation(s)
- Yuhang Zhou
- Health Management Center, Tongde Hospital of Zhejiang Province, Hangzhou, China
- The First Clinical Medical College, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Chaoyou Fang
- Department of Neurosurgery, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ling Yuan
- Department of Neurosurgery, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Mengchen Guo
- Department of Dermatology, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Xinyi Xu
- School of Medicine, Ningbo University, Ningbo, China
| | - Anwen Shao
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Anke Zhang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
| | - Danyang Zhou
- Health Management Center, Tongde Hospital of Zhejiang Province, Hangzhou, China.
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3
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Harrison RT, DeBacker JR, Trevino M, Bielefeld EC, Lobarinas E. Cochlear Preconditioning as a Modulator of Susceptibility to Hearing Loss. Antioxid Redox Signal 2022; 36:1215-1228. [PMID: 34011160 DOI: 10.1089/ars.2021.0055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Significance: Acquired sensorineural hearing loss is a major public health problem worldwide. The leading causes of sensorineural hearing loss are noise, aging, and ototoxic medications, with the key underlying pathology being damage to the cochlea. The review focuses on the phenomenon of preconditioning, in which the susceptibility to cochlear injury is reduced by exposing the ear to a stressful stimulus. Recent Advances: Cochlear conditioning has focused on the use of mono-modal conditioning, specifically conditioning the cochlea with moderate noise exposures before a traumatic exposure that causes permanent hearing loss. Recently, cross-modal conditioning has been explored more thoroughly, to prevent not only noise-induced hearing loss, but also age-related and drug-induced hearing losses. Critical Issues: Noise exposures that cause only temporary threshold shifts (TTSs) can cause long-term synaptopathy, injury to the synapses between the inner hair cells and spiral ganglion cells. This discovery has the potential to significantly alter the field of cochlear preconditioning with noise. Further, cochlear preconditioning can be the gateway to the development of clinically deployable therapeutics. Therefore, understanding the underlying mechanisms of conditioning is crucial for optimizing clinical protection against sensorineural hearing loss. Future Directions: Before the discovery of synaptopathy, noise exposures that caused only TTSs were believed to be either harmless or potentially beneficial. Any considerations of preconditioning with noise must consider the potential for injury to the synapses. Further, the discovery of different methods to precondition the cochlea against injury will yield new avenues for protection against hearing loss in the vulnerable populations. Antioxid. Redox Signal. 36, 1215-1228.
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Affiliation(s)
- Ryan T Harrison
- Department of Speech and Hearing Science, The Ohio State University, Columbus, Ohio, USA
| | - J Riley DeBacker
- Department of Speech and Hearing Science, The Ohio State University, Columbus, Ohio, USA
| | - Monica Trevino
- Callier Center for Communication Disorders, School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, Texas, USA
| | - Eric C Bielefeld
- Department of Speech and Hearing Science, The Ohio State University, Columbus, Ohio, USA
| | - Edward Lobarinas
- Callier Center for Communication Disorders, School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, Texas, USA
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Kador PF, Salvi R. Multifunctional Redox Modulators Protect Auditory, Visual, and Cognitive Function. Antioxid Redox Signal 2021; 36:1136-1157. [PMID: 34162214 PMCID: PMC9221172 DOI: 10.1089/ars.2021.0129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 06/18/2021] [Indexed: 12/26/2022]
Abstract
Significance: Oxidative stress contributes to vision, hearing and neurodegenerative disorders. Currently, no treatments prevent these disorders; therefore, there is an urgent need for redox modulators that can prevent these disorders. Recent Advances: Oxidative stress is associated with the generation of reactive oxygen species (ROS) and reactive nitrogen species, metal dyshomeostasis, and mitochondrial dysfunction. Here, we discuss the role that oxidative stress and metal dyshomeostasis play in hearing loss, visual impairments, and neurodegeneration and discuss the benefits of a new class of multifunctional redox modulators (MFRMs) that suppress sensory and neural degeneration. MFRMs not only reduce free radicals but also independently bind transition metals associated with the generation of hydroxyl radicals. The MFRMs redistribute zinc from neurotoxic amyloid beta zinc (Aβ:Zn) complexes to the cytoplasm, facilitating the degradation of Aβ plaques by matrix metalloprotease-2 (MMP-2). Although MFRMs bind copper (Cu1+, Cu2+), iron (Fe2+, Fe3+), zinc (Zn2+), and manganese (Mn2+), they do not deplete free cytoplasmic Zn+2 and they protect mitochondria from Mn+2-induced dysfunction. Oral administration of MFRMs reduce ROS-induced cataracts, protect the retina from light-induced degeneration, reduce neurotoxic Aβ:Zn plaque formation, and protect auditory hair cells from noise-induced hearing loss. Critical Issues: Regulation of redox balance is essential for clinical efficacy in maintaining sensory functions. Future Directions: Future use of these MFRMs requires additional pharmacokinetic, pharmacodynamics, and toxicological data to bring them into widespread clinical use. Additional animal studies are also needed to determine whether MFRMs can prevent neurodegeneration, dementia, and other forms of vision and hearing loss.
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Affiliation(s)
- Peter F. Kador
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, New York, USA
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5
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Ding D, Prolla T, Someya S, Manohar S, Salvi R. Roles of Bak and Sirt3 in Paraquat-Induced Cochlear Hair Cell Damage. Neurotox Res 2021; 39:1227-1237. [PMID: 33900547 DOI: 10.1007/s12640-021-00366-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 12/22/2022]
Abstract
Paraquat, a superoxide generator, can damage the cochlea causing an ototoxic hearing loss. The purpose of the study was to determine if deletion of Bak, a pro-apoptotic gene, would reduce paraquat ototoxicity or if deletion of Sirt3, which delays age-related hearing loss under caloric restriction, would increase paraquat ototoxicity. We tested these two hypotheses by treating postnatal day 3 cochlear cultures from Bak±, Bak-/-, Sirt3±, Sirt3-/-, and WT mice with paraquat and compared the results to a standard rat model of paraquat ototoxicity. Paraquat damaged nerve fibers and dose-dependently destroyed rat outer hair cells (OHCs) and inner hair cells (IHCs). Rat hair cell loss began in the base of the cochlea with a 10 μM dose and as the dose increased from 50 to 500 μM, the hair cell loss increased near the base of the cochlea and spread toward the apex of the cochlea. Rat OHC losses were consistently greater than IHC losses. Unexpectedly, in all mouse genotypes, paraquat-induced hair cell lesions were maximal near the apex of the cochlea and minimal near the base. This unusual damage gradient is opposite to that seen in paraquat-treated rats and in mice and rats treated with other ototoxic drugs. However, paraquat always induced greater OHC loss than IHC loss in all mouse strains. Contrary to our hypothesis, Bak deficient mice were more vulnerable to paraquat ototoxicity than WT mice (Bak-/- > Bak± > WT), suggesting that Bak plays a protective role against hair cell stress. Also, contrary to expectation, Sirt3-deficient mice did not differ significantly from WT mice, possibly due to the fact that Sirt3 was not experimentally upregulated in Sirt3-expressing mice prior to paraquat treatment. Our results show for the first time a gradient of ototoxic damage in mice that is greater in the apex than the base of the cochlea.
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MESH Headings
- Animals
- Animals, Newborn
- Cells, Cultured
- Cochlea/drug effects
- Cochlea/metabolism
- Cochlea/pathology
- Dose-Response Relationship, Drug
- Female
- Hair Cells, Auditory, Inner/drug effects
- Hair Cells, Auditory, Inner/metabolism
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Outer/drug effects
- Hair Cells, Auditory, Outer/metabolism
- Hair Cells, Auditory, Outer/pathology
- Herbicides/toxicity
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Organ Culture Techniques
- Paraquat/toxicity
- Rats
- Rats, Sprague-Dawley
- Sirtuin 3/deficiency
- Sirtuin 3/genetics
- bcl-2 Homologous Antagonist-Killer Protein/deficiency
- bcl-2 Homologous Antagonist-Killer Protein/genetics
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Affiliation(s)
- Dalian Ding
- Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA
| | - Tomas Prolla
- Department of Genetics and Medical Genetics, University of Wisconsin, 702 W Johnson St 1101, Madison, WI, 53715, USA
| | - Shinichi Someya
- Department of Aging and Geriatrics, University of Florida, Gainsville, FL, 32611, USA
| | - Senthilvelan Manohar
- Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA
| | - Richard Salvi
- Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA.
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Reastuty R, Haryuna TSH. Correlation of SOD and MDA Expression in the Organ of Corti and Changes in the Function of Outer Hair Cells Measured by DPOAE Examination in Noise-Exposed Rat Cochlea. Rep Biochem Mol Biol 2021; 10:41-49. [PMID: 34277867 PMCID: PMC8279712 DOI: 10.52547/rbmb.10.1.41] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 11/22/2020] [Indexed: 01/16/2023]
Abstract
BACKGROUND Hearing loss due to noise can cause the disturbances toward the quality of life and cause mechanical damage and metabolic decompensation. Distortion Product Otoacoustic Emission (DPOAE) is an examination to assess the sensory function of outer hair cells. Superoxide Dismutase (SOD) and Malondialdehyde (MDA) are markers of oxidative stress. The aim of this study was to identify the correlation between DPOAE examination and SOD and MDA expression in rats exposed to noise. METHODS This research was conducted on 27 rats which were divided into 3 groups, group 1 (control), group 2, and group 3 were groups with 100 dB and 110 dB noise exposure respectively. RESULTS Our findings show a decrease in SOD expression and DPOAE values as well as an increase in MDA expression in rats exposed to noise and there is a positive correlation between Signal to Noise Ratio (SNR) value with SOD expression (r= 0.733, p= 0.025) and a negative correlation between SNR value with MDA expression (r= -0.678, p= 0.045). CONCLUSION our study find the correlation of oxidant and antioxidant status values in the organ of corti and changes in the function of outer hair cells in noise-exposed rat models.
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Affiliation(s)
- Reastuty Reastuty
- Department of Otorhinolaryngology, Faculty of medicine, Universitas Sumatera Utara, 20155, Medan, North Sumatera, Indonesia.
| | - Tengku Siti Hajar Haryuna
- Department of Otorhinolaryngology, Faculty of medicine, Universitas Sumatera Utara, 20155, Medan, North Sumatera, Indonesia.
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7
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Fanaei H, Pourbakht A, Jafarzadeh S. Bilateral Carotid Artery Occlusion and Cochlear Oxidative Stress and Hearing Loss in Rats. Basic Clin Neurosci 2020; 11:821-829. [PMID: 33850619 PMCID: PMC8019843 DOI: 10.32598/bcn.11.6.1154.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/10/2018] [Accepted: 05/06/2019] [Indexed: 11/20/2022] Open
Abstract
Introduction: This study aimed to evaluate the effects of bilateral carotid artery occlusion on cochlear oxidative stress and hearing status in rats. Methods: The rats were divided into two sets. The first set was used for electrophysiological recording (click and 4 kHz tone burst auditory brainstem responses and electrocochleography) on the day before surgery and then on the first, fourth, and seventh days after surgery. Animals of the second set were used for biochemical analysis. The cochlea of animals in the second set was collected on the first, fourth, and seventh days after carotids occlusion for biochemical analysis. For the control groups, no carotids occlusion was done. For ischemia induction, both common carotid arteries were occluded for 20 minutes. Results: Electrophysiological analysis showed that burst auditory brainstem thresholds significantly elevated after common carotid arteries occlusion on the first, fourth, and seventh days after surgery with abnormal electrocochleography results at 75%, 70%, and 85% on the first, fourth, and seventh days after surgery, respectively. The electrophysiological finding confirmed by biochemical results that showed malondialdehyde and nitric oxide levels increased and superoxide dismutase and catalase activities decreased after occlusion in cochlea tissue. Conclusion: This study showed that bilateral common carotid artery occlusion increases cochlear oxidative stress and induces hearing loss in rats.
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Affiliation(s)
- Hamed Fanaei
- Department of Clinical Physiology, Faculty of Medical Sciences, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Akram Pourbakht
- Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
| | - Sadegh Jafarzadeh
- Department of Audiology, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
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8
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Novel oral multifunctional antioxidant prevents noise-induced hearing loss and hair cell loss. Hear Res 2020; 388:107880. [PMID: 31945692 DOI: 10.1016/j.heares.2019.107880] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 12/09/2019] [Accepted: 12/27/2019] [Indexed: 12/20/2022]
Abstract
Oxidative stress is a major contributor to noise-induced hearing loss, the most common cause of hearing loss among military personnel and young adults. HK-2 is a potent, orally-active, multifunctional, redox-modulating drug that has been shown to protect against a wide range of neurological disorders with no observed side effects. HK-2 protected cochlear HEI-OC1 cells against various forms of experimentally-induced oxidative stressors similar to those observed during and after intense noise exposure. The mechanisms by which HK-2 protects cells is twofold, first by its ability to reduce oxidative stress generated by free radicals, and second, by its ability to complex biologically active transition metals such as Fe+2, thus reducing their availability to participate in the Fenton reaction where highly toxic hydroxyl radicals are generated. For the rat in vivo studies, HK-2 provided significant protection against noise-induced hearing loss and hair cell loss. Noise-induced hearing loss was induced by an 8-16 kHz octave band noises presented for 8 h/d for 21 days at an intensity of 95 dB SPL. In the Prevention study, HK-2 was administered orally beginning 5 days before the start of the noise and ending 10 days after the noise. Treatment with HK-2 dose-dependently reduced the amount of noise-induced hearing impairment, reflected in the cochlear compound action potential, and noise-induced hair cell loss. In a subsequent Rescue experiment in which HK-2 was administered for 10 days starting after the noise was turned off, HK-2 also significantly reduced the amount of hearing impairment, but the effect size was substantially less than in the Prevention studies. HK-2 alone did not adversely affect HEI-OC1 cell viability, nor did it cause any adverse changes in rat body weight, behavior, cochlear function or hair cell integrity. Thus, HK-2 is a novel, safe, orally-deliverable and highly effective otoprotective compound with considerable potential for preventing hearing loss from noise and other hearing disorders linked to excessive oxidative stress.
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9
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Aazh H, Heinonen-Guzejev M, Moore BCJ. The relationship between hearing loss and insomnia for patients with tinnitus. Int J Audiol 2019; 59:68-72. [DOI: 10.1080/14992027.2019.1654621] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Hashir Aazh
- Department of Audiology, Royal Surrey County Hospital NHS Foundation Trust, Guildford, UK
| | - Marja Heinonen-Guzejev
- Department of Public Health, Faculty of Medicine, Clinicum, University of Helsinki, Helsinki, Finland
| | - Brian C. J. Moore
- Department of Experimental Psychology, University of Cambridge, Cambridge, UK
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10
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Silver MK, Shao J, Li M, Ji C, Chen M, Xia Y, Lozoff B, Meeker JD. Prenatal exposure to the herbicide 2,4-D is associated with deficits in auditory processing during infancy. ENVIRONMENTAL RESEARCH 2019; 172:486-494. [PMID: 30851698 PMCID: PMC6511332 DOI: 10.1016/j.envres.2019.02.046] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 02/21/2019] [Accepted: 02/28/2019] [Indexed: 05/24/2023]
Abstract
INTRODUCTION Despite widespread use, many herbicides and fungicides are not well studied for neurological effects. Fetal and infant brains are rapidly developing, yet the effects of early-life exposure to these classes of pesticides on visual and auditory function are unknown. Here we examined the effects of prenatal herbicide and fungicide exposure on infant grating visual acuity (VA) and auditory brainstem response (ABR). METHODS 9 herbicides and 13 fungicides were measured in umbilical cord blood plasma from a cohort of infants in Fuyang County, China (n = 232). Grating VA and ABR latencies for waves I, III, V were measured at 3 time points: 6 weeks, 9 months, and 18 months. Outcomes included VA score, ABR wave V latency and ABR central conduction time (CCT [wave V- wave I]). Pesticides were analyzed as 3-level ordinal (non-detect [ND]/medium/high), or dichotomous (ND/detect), depending on detection rates. Linear mixed models were used to evaluate relations between pesticides and VA and ABR outcomes. RESULTS 2,4-dichloroacetic acid (2,4-D), prometryn, simazine, and tetrahydrophthalamide (THPI, a metabolite of captan) were detected in 27%, 81%, 17%, and 16% of samples, respectively. Infants prenatally exposed to 2,4-D had slower auditory response times at 6 weeks. Infants with cord levels of 2,4-D > 1.17 ng/mL had wave V latencies that were 0.12 (95% CI: 0.03, 0.22) ms slower (p = 0.01) and overall CCTs that were 0.15 (95% CI:0.05, 0.25) ms slower (p = 0.003) than infants with non-detectable 2,4-D in their cord blood. No other statistically significant findings were observed for the other herbicides and fungicides or for the grating VA outcome. CONCLUSIONS Prenatal exposure to the herbicide 2,4-D was associated with slower auditory signal transmission in early infancy. ABR latencies reflect auditory pathway maturation and longer latencies may indicate delayed auditory development.
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Affiliation(s)
- Monica K Silver
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Jie Shao
- Department of Child Health Care, Children's Hospital Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China.
| | - Mingyan Li
- Department of Child Health Care, Children's Hospital Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China.
| | - Chai Ji
- Department of Child Health Care, Children's Hospital Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China.
| | - Minjian Chen
- Institute of Toxicology, Nanjing Medical University, Nanjing 210029, China.
| | - Yankai Xia
- Institute of Toxicology, Nanjing Medical University, Nanjing 210029, China.
| | - Betsy Lozoff
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - John D Meeker
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI, 48109, USA.
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11
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Morioka S, Sakaguchi H, Yamaguchi T, Ninoyu Y, Mohri H, Nakamura T, Hisa Y, Ogita K, Saito N, Ueyama T. Hearing vulnerability after noise exposure in a mouse model of reactive oxygen species overproduction. J Neurochem 2018; 146:459-473. [PMID: 29675997 DOI: 10.1111/jnc.14451] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/09/2018] [Accepted: 04/10/2018] [Indexed: 12/20/2022]
Abstract
Previous studies have convincingly argued that reactive oxygen species (ROS) contribute to the development of several major types of sensorineural hearing loss, such as noise-induced hearing loss (NIHL), drug-induced hearing loss, and age-related hearing loss. However, the underlying molecular mechanisms induced by ROS in these pathologies remain unclear. To resolve this issue, we established an in vivo model of ROS overproduction by generating a transgenic (TG) mouse line expressing the human NADPH oxidase 4 (NOX4, NOX4-TG mice), which is a constitutively active ROS-producing enzyme that does not require stimulation or an activator. Overproduction of ROS was detected at the cochlea of the inner ear in NOX4-TG mice, but they showed normal hearing function under baseline conditions. However, they demonstrated hearing function vulnerability, especially at high-frequency sounds, upon exposure to intense noise, which was accompanied by loss of cochlear outer hair cells (OHCs). The vulnerability to loss of hearing function and OHCs was rescued by treatment with the antioxidant Tempol. Additionally, we found increased protein levels of the heat-shock protein 47 (HSP47) in models using HEK293 cells, including H2 O2 treatment and cells with stable and transient expression of NOX4. Furthermore, the up-regulated levels of Hsp47 were observed in both the cochlea and heart of NOX4-TG mice. Thus, antioxidant therapy is a promising approach for the treatment of NIHL. Hsp47 may be an endogenous antioxidant factor, compensating for the chronic ROS overexposure in vivo, and counteracting ROS-related hearing loss.
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Affiliation(s)
- Shigefumi Morioka
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan.,Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hirofumi Sakaguchi
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Taro Yamaguchi
- Laboratory of Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Osaka, Japan
| | - Yuzuru Ninoyu
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan
| | - Hiroaki Mohri
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan
| | - Takashi Nakamura
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan
| | - Yasuo Hisa
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Faculty of Health and Medical Sciences, Kyoto Gakuen University, Kyoto, Japan
| | - Kiyokazu Ogita
- Laboratory of Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Osaka, Japan
| | - Naoaki Saito
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan
| | - Takehiko Ueyama
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe, Japan
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12
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Zhang J, Sun H, Salvi R, Ding D. Paraquat initially damages cochlear support cells leading to anoikis-like hair cell death. Hear Res 2018; 364:129-141. [PMID: 29563067 PMCID: PMC5984146 DOI: 10.1016/j.heares.2018.03.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/20/2018] [Accepted: 03/09/2018] [Indexed: 12/11/2022]
Abstract
Paraquat (PQ), one of the most widely used herbicides, is extremely dangerous because it generates the highly toxic superoxide radical. When paraquat was applied to cochlear organotypic cultures, it not only damaged the outer hair cells (OHCs) and inner hair cells (IHCs), but also caused dislocation of the hair cell rows. We hypothesized that the dislocation arose from damage to the support cells (SCs) that anchors hair cells within the epithelium. To test this hypothesis, rat postnatal cochlear cultures were treated with PQ. Shortly after PQ treatment, the rows of OHCs separated from one another and migrated radially away from IHCs suggesting loss of cell-cell adhesion that hold the hair cells in proper alignment. Hair cells dislocation was associated with extensive loss of SCs in the organ of Corti, loss of tympanic border cells (TBCs) beneath the basilar membrane, the early appearance of superoxide staining and caspase-8 labeling in SCs below the OHCs and disintegration of E-cadherin and β-catenin in the organ of Corti. Damage to the TBCs and SCs occurred prior to loss of OHC or IHC loss suggesting a form of detachment-induced apoptosis referred to as anoikis.
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Affiliation(s)
- Jianhui Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, China; Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA
| | - Hong Sun
- Department of Otorhinolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, China; Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA
| | - Richard Salvi
- Department of Otorhinolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, China; Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Audiology and Speech-Language Pathology, Asia University, Taichung, Taiwan, ROC
| | - Dalian Ding
- Department of Otorhinolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, China; Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA.
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13
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Zhuang W, Li T, Wang C, Shi X, Li Y, Zhang S, Zhao Z, Dong H, Qiao Y. Berberine exerts antioxidant effects via protection of spiral ganglion cells against cytomegalovirus-induced apoptosis. Free Radic Biol Med 2018; 121:127-135. [PMID: 29715550 DOI: 10.1016/j.freeradbiomed.2018.04.575] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 12/20/2022]
Abstract
Cytomegalovirus (CMV) is the leading cause of sensorineural hearing loss (SNHL) in children because of its damage to the cochlea and spiral ganglion cells. Therefore, it has become a top priority to devise new methods to effectively protect spiral ganglion cells from damage. Berberine (BBR) has gained attention for its vast beneficial biological effects through immunomodulation, and its anti-inflammatory and anti-apoptosis properties. However, the effect of BBR on spiral ganglion cells and molecular mechanisms are still unclear. This study aims to investigate whether BBR has an anti-apoptosis effect in CMV-induced apoptosis in cultured spiral ganglion cells and explore the possible mechanism. In this study, TUNEL and MTT assays significantly demonstrated that low doses of BBR did not promote cell apoptosis and they also inhibited the CMV-induced cultured spiral ganglion cell apoptosis. Immunofluorescence and Western blot assays indicated that the anti-apoptosis effect of BBR was related to Nox3. Mitochondrial calcium and Western blot assays revealed that NMDAR1 mediated this anti-apoptosis effect. Our results demonstrated that BBR exerted an anti-apoptosis effect against CMV in cultured spiral ganglion cells, and the mechanism is related to NMDAR1/Nox3-mediated mitochondrial reactive oxygen species (ROS) generation.
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Affiliation(s)
- Wei Zhuang
- Clinical Hearing Center, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221006, Jiangsu, China
| | - Ting Li
- Research Facility Center for Morphology, Xuzhou Medical University, Xuzhou 221004, China
| | - Caiji Wang
- The Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Xi Shi
- The Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Yalan Li
- The Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Shili Zhang
- The Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Zeqi Zhao
- The Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
| | - Hongyan Dong
- Research Facility Center for Morphology, Xuzhou Medical University, Xuzhou 221004, China.
| | - Yuehua Qiao
- Clinical Hearing Center, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221006, Jiangsu, China; The Institute of Audiology and Balance Science, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China.
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14
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Münzel T, Sørensen M, Schmidt F, Schmidt E, Steven S, Kröller-Schön S, Daiber A. The Adverse Effects of Environmental Noise Exposure on Oxidative Stress and Cardiovascular Risk. Antioxid Redox Signal 2018; 28:873-908. [PMID: 29350061 PMCID: PMC5898791 DOI: 10.1089/ars.2017.7118] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 11/11/2017] [Accepted: 11/14/2017] [Indexed: 12/29/2022]
Abstract
Epidemiological studies have provided evidence that traffic noise exposure is linked to cardiovascular diseases such as arterial hypertension, myocardial infarction, and stroke. Noise is a nonspecific stressor that activates the autonomous nervous system and endocrine signaling. According to the noise reaction model introduced by Babisch and colleagues, chronic low levels of noise can cause so-called nonauditory effects, such as disturbances of activity, sleep, and communication, which can trigger a number of emotional responses, including annoyance and subsequent stress. Chronic stress in turn is associated with cardiovascular risk factors, comprising increased blood pressure and dyslipidemia, increased blood viscosity and blood glucose, and activation of blood clotting factors, in animal models and humans. Persistent chronic noise exposure increases the risk of cardiometabolic diseases, including arterial hypertension, coronary artery disease, diabetes mellitus type 2, and stroke. Recently, we demonstrated that aircraft noise exposure during nighttime can induce endothelial dysfunction in healthy subjects and is even more pronounced in coronary artery disease patients. Importantly, impaired endothelial function was ameliorated by acute oral treatment with the antioxidant vitamin C, suggesting that excessive production of reactive oxygen species contributes to this phenomenon. More recently, we introduced a novel animal model of aircraft noise exposure characterizing the underlying molecular mechanisms leading to noise-dependent adverse oxidative stress-related effects on the vasculature. With the present review, we want to provide an overview of epidemiological, translational clinical, and preclinical noise research addressing the nonauditory, adverse effects of noise exposure with focus on oxidative stress. Antioxid. Redox Signal. 28, 873-908.
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Affiliation(s)
- Thomas Münzel
- The Center for Cardiology, Cardiology 1, Johannes Gutenberg University Medical Center, Mainz, Germany
| | - Mette Sørensen
- Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Frank Schmidt
- The Center for Cardiology, Cardiology 1, Johannes Gutenberg University Medical Center, Mainz, Germany
| | - Erwin Schmidt
- Institute for Molecular Genetics, Johannes Gutenberg University, Mainz, Germany
| | - Sebastian Steven
- The Center for Cardiology, Cardiology 1, Johannes Gutenberg University Medical Center, Mainz, Germany
| | - Swenja Kröller-Schön
- The Center for Cardiology, Cardiology 1, Johannes Gutenberg University Medical Center, Mainz, Germany
| | - Andreas Daiber
- The Center for Cardiology, Cardiology 1, Johannes Gutenberg University Medical Center, Mainz, Germany
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15
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Sena TRR, Dourado SSF, Lima LV, Antoniolli ÂR. The hearing of rural workers exposed to noise and pesticides. Noise Health 2018; 20:23-26. [PMID: 29457603 PMCID: PMC5843986 DOI: 10.4103/nah.nah_70_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In work environments, different physical and chemical agents that may pose a risk to workers‘ hearing health coexist. In this context, occupational hearing loss stands out. It has mostly been attributed to only noise exposure, although there are other agents, that is, pesticides that might contribute to occupational hearing loss. In this report, two cases will be presented that consider rural workers exposed to pesticides and intense noise generated by an adapted rudimentary vehicle. The noise measured in this vehicle was 88.3 dBA up to 93.4 dBA. Pure-tone audiometry, distortion product otoacoustic emissions, and high-frequency audiometry tests were performed. This report is unusual because of the short time of exposure to noise and pesticides and the hearing loss found, indicating a synergy between those agents.
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Affiliation(s)
- Tereza R R Sena
- Department of Audiology and Speech Therapy, Doctoral Program in Health Science, Federal University of Sergipe, Brazil
| | - Solano S F Dourado
- Graduate Program in Physiological Science, Doctoral Program in Health Science, Federal University of Sergipe, Brazil
| | - Lucas V Lima
- Graduate Program in Physiological Science, Doctoral Program in Health Science, Federal University of Sergipe, Brazil
| | - Ângelo R Antoniolli
- Department of Physiology, Doctoral Program in Health Science, Federal University of Sergipe, Brazil
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16
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Lim HM, Kang W, Park WJ, Jang KH, Ann JS, Moon JD. Insomnia and hearing impairment among occupational noise exposed male workers. Ann Occup Environ Med 2017; 29:36. [PMID: 28824813 PMCID: PMC5558741 DOI: 10.1186/s40557-017-0195-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 08/04/2017] [Indexed: 12/20/2022] Open
Abstract
Background The aim of this study was to investigate the association between insomnia and hearing impairment among workers exposed to occupational noise. Methods This study included 809 male workers exposed to occupational noise. The participants underwent audiometric testing, and their insomnia was examined based on the Insomnia Severity Index test. Hearing impairment was defined as hearing threshold >25 dB hearing level in the range of 1–4 kHz. Results According to analysis of covariance, it was observed that pure tone audiometry thresholds at 1–2 kHz in the right ear and at 1 kHz in the left ear were significantly higher among workers with insomnia compared to those with no insomnia. Multiple logistic regression analysis of insomnia for hearing impairments was performed, which showed the odds ratio was 1.806 (95% confidence intervals: 1.022–3.188, p = 0.042) after adjustment for age, working period, noise level, snoring, use of protection devices, diabetes mellitus, hypertension, smoking, alcohol consumption, regular exercise, waist circumference, total cholesterol, triglyceride and high density lipoprotein cholesterol. Conclusion Insomnia could be associated with hearing impairment in workers who are exposed to occupational noise. Additionally, insomnia may be associated with decreased hearing at low frequencies. Especially, more efforts are required to improve the quality of sleep for workers who are exposed to loud occupational noise. Further well- designed prospective studies are needed to clarify the relationship between insomnia and hearing impairment.
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Affiliation(s)
- Hyeong-Min Lim
- Department of Occupational and Environmental Medicine, Chonnam National University Hwasun Hospital, 322 Seoyang-ro, Hwasun-gun, Jeollanam-do, 58128 Republic of Korea
| | - WonYang Kang
- Department of Occupational and Environmental Medicine, Chonnam National University Hwasun Hospital, 322 Seoyang-ro, Hwasun-gun, Jeollanam-do, 58128 Republic of Korea
| | - Won-Ju Park
- Department of Occupational and Environmental Medicine, Chonnam National University Hwasun Hospital, 322 Seoyang-ro, Hwasun-gun, Jeollanam-do, 58128 Republic of Korea
| | - Keun-Ho Jang
- Department of Occupational and Environmental Medicine, Mokpo Christian Hospital, 303 Baengnyeon-daero, Mokpo-si, Jeollanam-do, Republic of Korea
| | - Ji-Sung Ann
- Department of Occupational and Environmental Medicine, Chonnam National University Hwasun Hospital, 322 Seoyang-ro, Hwasun-gun, Jeollanam-do, 58128 Republic of Korea
| | - Jai-Dong Moon
- Department of Occupational and Environmental Medicine, Chonnam National University Hwasun Hospital, 322 Seoyang-ro, Hwasun-gun, Jeollanam-do, 58128 Republic of Korea
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17
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Dietrich A, Steinritz D, Gudermann T. Transient receptor potential (TRP) channels as molecular targets in lung toxicology and associated diseases. Cell Calcium 2017; 67:123-137. [PMID: 28499580 DOI: 10.1016/j.ceca.2017.04.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 04/21/2017] [Accepted: 04/21/2017] [Indexed: 12/24/2022]
Abstract
The lungs as the gateways of our body to the external environment are essential for gas exchange. They are also exposed to toxicants from two sides, the airways and the vasculature. Apart from naturally produced toxic agents, millions of human made chemicals were produced since the beginning of the industrial revolution whose toxicity still needs to be determined. While the knowledge about toxic substances is increasing only slowly, a paradigm shift regarding the proposed mechanisms of toxicity at the plasma membrane emerged. According to their broad-range chemical reactivity, the mechanism of lung injury evoked by these agents has long been described as rather unspecific. Consequently, therapeutic options are still restricted to symptomatic treatment. The identification of molecular down-stream effectors in cells was a major step forward in the mechanistic understanding of the action of toxic chemicals and will pave the way for more causal and specific toxicity testing as well as therapeutic options. In this context, the involvement of Transient Receptor Potential (TRP) channels as chemosensors involved in the detection and effectors of toxicant action is an attractive concept intensively discussed in the scientific community. In this review we will summarize recent evidence for an involvement of TRP channels (TRPA1, TRPC4, TRPC6, TRPV1, TRPV4, TRPM2 and TRPM8) expressed in the lung in pathways of toxin sensing and as mediators of lung inflammation and associated diseases like asthma, COPD, lung fibrosis and edema formation. Specific modulators of these channels may offer new therapeutic options in the future and will endorse strategies for a causal, specifically tailored treatment based on the mechanistic understanding of molecular events induced by lung-toxic agents.
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Affiliation(s)
- Alexander Dietrich
- Walther-Straub-Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), LMU Munich, Germany.
| | - Dirk Steinritz
- Walther-Straub-Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), LMU Munich, Germany; Bundeswehr-Institute of Pharmacology and Toxicology, Munich, Germany
| | - Thomas Gudermann
- Walther-Straub-Institute of Pharmacology and Toxicology, Member of the German Center for Lung Research (DZL), LMU Munich, Germany
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18
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França DMVR, Bender Moreira Lacerda A, Lobato D, Ribas A, Ziliotto Dias K, Leroux T, Fuente A. Adverse effects of pesticides on central auditory functions in tobacco growers. Int J Audiol 2017; 56:233-241. [PMID: 27869513 DOI: 10.1080/14992027.2016.1255787] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To investigate the effects of exposure to pesticides on the central auditory functions (CAF) of Brazilian tobacco growers. DESIGN This was a cross-sectional study carried out between 2010 and 2012. Participants were evaluated with two behavioural procedures to investigate CAF, the random gap detection test (RGDT) and the dichotic digit test in Portuguese (DDT). STUDY SAMPLE A total of 22 growers exposed to pesticides (study group) and 21 subjects who were not exposed to pesticides (control group) were selected. RESULTS No significant differences between groups were observed for pure-tone thresholds. A significant association between pesticide exposure and the results for RGDT and DDT was found. Significant differences between pesticide-exposed and nonexposed subjects were found for RGDT frequency average and DDT binaural average, when including age and hearing level as covariates. Age was significantly associated with RGDT frequency average, DDT left ear score, DDT binaural average and DDT right ear advantage. Hearing levels were not significantly associated with any of the test scores. The relative risk of failing the DDT and RGDT for the study group was 1.88 (95% CI: 1.10-3.20) and 1.74 (95% CI: 1.06-2.86), respectively, as compared with the control group. CONCLUSIONS The results showed that tobacco growers exposed to pesticides exhibited signs of central auditory dysfunction characterised by decrements in temporal processing and binaural integration processes/abilities.
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Affiliation(s)
| | | | - Diolen Lobato
- b Universidade Tuiuti do Paraná , Curitiba , Brazil , and
| | - Angela Ribas
- b Universidade Tuiuti do Paraná , Curitiba , Brazil , and
| | | | - Tony Leroux
- d Université de Montréal , Montreal , Canada
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The Role of the Transcription Factor Foxo3 in Hearing Maintenance: Informed Speculation on a New Player in the Cochlea. BIOMED RESEARCH INTERNATIONAL 2016; 2016:1870675. [PMID: 27818997 PMCID: PMC5081746 DOI: 10.1155/2016/1870675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/31/2016] [Accepted: 09/19/2016] [Indexed: 01/12/2023]
Abstract
Molecular genetics has proven to be a powerful approach for understanding early-onset hearing loss. Recent work in late-onset hearing loss uses mouse genetics to identify molecular mechanisms that promote the maintenance of hearing. One such gene, Foxo3, is ontologically involved in preserving mitochondrial function. Significant evidence exists to support the idea that mitochondrial dysfunction is correlated with and can be causal for hearing loss. Foxo3 is also ontologically implicated in driving the circadian cycle, which has recently been shown to influence the molecular response to noise damage. In this review, the molecular framework connecting these cellular processes is discussed in relation to the cellular pathologies observed in human specimens of late-onset hearing loss. In bringing these observations together, the possibility arises that distinct molecular mechanisms work in multiple cell types to preserve hearing. This diversity offers great opportunities to understand and manipulate genetic processes for therapeutic gain.
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20
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A comprehensive study of oxidative stress in sudden hearing loss. Eur Arch Otorhinolaryngol 2016; 274:1301-1308. [PMID: 27614879 DOI: 10.1007/s00405-016-4301-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/06/2016] [Indexed: 10/21/2022]
Abstract
Little is known about the association between idiopathic sudden sensorineural hearing loss (ISSNHL) and oxidative stress. We investigated changes in a wide range of oxidants and antioxidants to create a comprehensive picture of oxidative imbalance. In the peripheral blood of 50 ISSNHL patients and 50 healthy subjects, total oxidant status (TOS), total antioxidant status (TAS), paraoxonase (PON), thiol/disulphide levels were measured. Moreover, a global oxidative stress index, reflecting both oxidative and antioxidant counterparts, was also calculated. One-way analysis between oxidative markers and severity of hearing loss were evaluated. The ISSNHL patients showed significantly higher TOS levels than controls (6.02 ± 3.17 vs. 4.5 ± 2.22; p = 0.018). The oxidative index was also significantly higher in patients than controls (0.39 ± 0.19 vs. 0.3 ± 0.14; p = 0.035). TAS, PON, native thiol, and total thiol were not altered. There was no statistical significance between oxidative markers and severity of hearing loss. The binary logistic regression model revealed that disulphide and TOS were associated with ISSNHL. There are alterations in a wide array of oxidants and antioxidants, with balance shifting toward increased oxidative stress in ISSNHL. Our findings may suggest endothelial dysfunction in ISSNHL etiopathogenesis.
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21
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Sturza J, Silver MK, Xu L, Li M, Mai X, Xia Y, Shao J, Lozoff B, Meeker J. Prenatal exposure to multiple pesticides is associated with auditory brainstem response at 9months in a cohort study of Chinese infants. ENVIRONMENT INTERNATIONAL 2016; 92-93:478-485. [PMID: 27166702 PMCID: PMC4902769 DOI: 10.1016/j.envint.2016.04.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 04/13/2016] [Accepted: 04/22/2016] [Indexed: 05/29/2023]
Abstract
BACKGROUND Pesticides are associated with poorer neurodevelopmental outcomes, but little is known about the effects on sensory functioning. METHODS Auditory brainstem response (ABR) and pesticide data were available for 27 healthy, full-term 9-month-old infants participating in a larger study of early iron deficiency and neurodevelopment. Cord blood was analyzed by gas chromatography-mass spectrometry for levels of 20 common pesticides. The ABR forward-masking condition consisted of a click stimulus (masker) delivered via ear canal transducers followed by an identical stimulus delayed by 8, 16, or 64 milliseconds (ms). ABR peak latencies were evaluated as a function of masker-stimulus time interval. Shorter wave latencies reflect faster neural conduction, more mature auditory pathways, and greater degree of myelination. Linear regression models were used to evaluate associations between total number of pesticides detected and ABR outcomes. We considered an additive or synergistic effect of poor iron status by stratifying our analysis by newborn ferritin (based on median split). RESULTS Infants in the sample were highly exposed to pesticides; a mean of 4.1 pesticides were detected (range 0-9). ABR Wave V latency and central conduction time (CCT) were associated with the number of pesticides detected in cord blood for the 64ms and non-masker conditions. A similar pattern seen for CCT from the 8ms and 16ms conditions, although statistical significance was not reached. Increased pesticide exposure was associated with longer latency. The relation between number of pesticides detected in cord blood and CCT depended on the infant's cord blood ferritin level. Specifically, the relation was present in the lower cord blood ferritin group but not the higher cord blood ferritin group. CONCLUSIONS ABR processing was slower in infants with greater prenatal pesticide exposure, indicating impaired neuromaturation. Infants with lower cord blood ferritin appeared to be more sensitive to the effects of prenatal pesticide exposure on ABR latency delay, suggesting an additive or multiplicative effect.
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Affiliation(s)
- Julie Sturza
- Center for Human Growth and Development, University of Michigan, Ann Arbor, MI, USA.
| | - Monica K Silver
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA.
| | - Lin Xu
- Department of Child Health Care, Children's Hospital Zhejiang University School of Medicine, Zhejiang, China.
| | - Mingyan Li
- Department of Child Health Care, Children's Hospital Zhejiang University School of Medicine, Zhejiang, China.
| | - Xiaoqin Mai
- Department of Psychology, Renmin University of China, Beijing, China.
| | - Yankai Xia
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing, China.
| | - Jie Shao
- Department of Child Health Care, Children's Hospital Zhejiang University School of Medicine, Zhejiang, China.
| | - Betsy Lozoff
- Center for Human Growth and Development, University of Michigan, Ann Arbor, MI, USA.
| | - John Meeker
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA.
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22
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Abstract
Safety pharmacology satisfies a key requirement in the process of drug development. Safety pharmacology studies are required to assess the impact of a new chemical entity (NCE) or biotechnology-derived product for human use on vital systems, such as those subserving auditory function. Safety pharmacology studies accordingly are defined as those studies that investigate the potential undesirable effects of a substance on auditory functions in relation to exposure in and above the therapeutic range. Auditory safety studies should be designed with the primary objective of determining how administration of a compound influences normal hearing. If an effect on hearing is identified, then it is necessary to determine through histopathology the underlying mechanism for the observed hearing loss. Since the auditory system contains a heterogeneous mixture of structural and cellular components that are organized in a very complex and integrated manner, it is necessary to clearly identify the underlying primary mechanism or target of the new chemical entity that produced the hearing loss. This chapter will highlight major components of auditory function with regard to potential opportunities for drug interaction. Aspects of designing ototoxicity studies will be discussed with an emphasis on standards deemed necessary by the US Food and Drug Administration. Additionally, classes of ototoxic compounds and their proposed mechanisms of action are described in depth.
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Gatto M, Fioretti M, Fabrizi G, Gherardi M, Strafella E, Santarelli L. Effects of potential neurotoxic pesticides on hearing loss: A review. Neurotoxicology 2014; 42:24-32. [DOI: 10.1016/j.neuro.2014.03.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 03/20/2014] [Accepted: 03/22/2014] [Indexed: 11/25/2022]
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Viologen-phosphorus dendrimers exhibit minor toxicity against a murine neuroblastoma cell line. Cell Mol Biol Lett 2013; 18:459-78. [PMID: 23893290 PMCID: PMC6275709 DOI: 10.2478/s11658-013-0100-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 07/18/2013] [Indexed: 12/16/2022] Open
Abstract
Dendrimers containing viologen (derivatives of 4,4′-bipyridyl) units in their structure have been demonstrated to exhibit antiviral activity against human immunodeficiency virus (HIV-1). It has also recently been revealed that novel dendrimers with both viologen units and phosphorus groups in their structure show different antimicrobial, cytotoxic and hemotoxic properties, and have the ability to influence the activity of cholinesterases and to inhibit α-synuclein fibrillation. Since the influence of viologen-phosphorus structures on basic cellular processes had not been investigated, we examined the impact of such macromolecules on the murine neuroblastoma cell line (N2a). We selected three water-soluble viologen-phosphorus (VPD) dendrimers, which differ in their core structure, number of viologen units and number and type of surface groups, and analyzed several aspects of the cellular response. These included cell viability, generation of reactive oxygen species (ROS), alterations in mitochondrial activity, morphological modifications, and the induction of apoptosis and necrosis. The MTT assay results suggest that all of the tested dendrimers are only slightly cytotoxic. Although some changes in ROS formation and mitochondrial function were detected, the three compounds did not induce apoptosis or necrosis. In light of these results, we can assume that the tested VPD are relatively safe for mouse neuroblastoma cells. Although more research on their safety is needed, VPD seem to be promising nanoparticles for further biomedical investigation.
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Büch T, Schäfer E, Steinritz D, Dietrich A, Gudermann T. Chemosensory TRP Channels in the Respiratory Tract: Role in Toxic Lung Injury and Potential as “Sweet Spots” for Targeted Therapies. Rev Physiol Biochem Pharmacol 2013; 165:31-65. [DOI: 10.1007/112_2012_10] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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An Src-protein tyrosine kinase inhibitor to reduce cisplatin ototoxicity while preserving its antitumor effect. Anticancer Drugs 2013; 24:43-51. [DOI: 10.1097/cad.0b013e32835739fd] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Park MH, Lee HS, Song JJ, Chang SO, Oh SH. Increased activity of mitochondrial respiratory chain complex in noise-damaged rat cochlea. Acta Otolaryngol 2012; 132 Suppl 1:S134-41. [PMID: 22582776 DOI: 10.3109/00016489.2012.659755] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
CONCLUSION Functional changes of mitochondrial respiratory chain (MRC) and hearing threshold shifts were observed after noise exposure and the pattern was different depending on the extent of the noise damage. OBJECTIVES The aim of this study was to reveal any functional changes of the MRC enzyme in outer hair cells after noise damage. METHODS Sprague-Dawley rats were used and divided into three groups including normal control group and noise exposure for 1 h and 5 h. White band noise was used with 120 dB SPL. We measured hearing threshold and activity of succinate dehydrogenase (SDH) before noise exposure, and immediately and 1, 3, 7, and 14 days after noise exposure in each group. Immunostaining using monoclonal anti-MRC complex V subunit α was performed. Transmission electron microscopy (TEM) was carried out. RESULTS The hearing threshold level changed depending on the exposure time in both the noise-exposed groups. In the 1 h group, hearing was improved after 1 day, and in the 5 h group, hearing was measured after 7 days. Changes in SDH activity were observed at the third day in the 1 h group and at the seventh day in the 5 h group. The expression level of MRC complex V was increased after noise exposure. TEM showed mitochondrial damage.
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MESH Headings
- Animals
- Auditory Threshold
- Blotting, Western
- Disease Models, Animal
- Electron Transport/physiology
- Evoked Potentials, Auditory, Brain Stem
- Hair Cells, Auditory/metabolism
- Hair Cells, Auditory/ultrastructure
- Hearing Loss, Noise-Induced/metabolism
- Hearing Loss, Noise-Induced/pathology
- Hearing Loss, Noise-Induced/physiopathology
- Immunohistochemistry
- Microscopy, Electron, Transmission
- Mitochondria/metabolism
- Mitochondria/ultrastructure
- Rats
- Rats, Sprague-Dawley
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Affiliation(s)
- Min-Hyun Park
- Department of Otorhinolaryngology, Boramae Medical Center, Seoul Metropolitan Government-Seoul National University, Seoul, Korea.
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Rybak LP, Mukherjea D, Jajoo S, Kaur T, Ramkumar V. siRNA-mediated knock-down of NOX3: therapy for hearing loss? Cell Mol Life Sci 2012; 69:2429-34. [PMID: 22562580 DOI: 10.1007/s00018-012-1016-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 04/18/2012] [Accepted: 04/20/2012] [Indexed: 11/27/2022]
Abstract
Cisplatin is a widely used chemotherapeutic agent that causes significant hearing loss. Previous studies have shown that cisplatin exposure is associated with increase in reactive oxygen species (ROS) in the cochlea. The inner ear expresses a unique isoform of NADPH oxidase, NOX3. This enzyme may be the primary source of ROS generation in the cochlea. The knockdown of NOX3 by pretreatment with siRNA prevented cisplatin ototoxicity, as demonstrated by preservation of hearing thresholds and inner ear sensory cells. Trans-tympanic NOX3 siRNA reduced the expression of NOX3 and biomarkers of cochlear damage, including transient receptor vanilloid 1 (TRPV1) channel and kidney injury molecule-1 (KIM-1) in cochlear tissues. In addition, siRNA against NOX3 reduced apoptosis as demonstrated by TUNEL staining, and prevented the increased expression of Bax and abrogated the decrease in Bcl2 expression following cisplatin administration. Trans-tympanic administration of siRNA directed against NOX3 may provide a useful method of attenuating cisplatin ototoxicity. In this paper, we review recent publications dealing with the role of NOX3 in ototoxicity and the effects of siRNA against cisplatin-induced hearing loss.
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Affiliation(s)
- Leonard P Rybak
- Department of Surgery, Division of Otolaryngology, Southern Illinois University, School of Medicine, Springfield, IL 62794-9649, USA.
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Jayasinghe SS, Pathirana KD. Effects of deliberate ingestion of organophosphate or paraquat on brain stem auditory-evoked potentials. J Med Toxicol 2012; 7:277-80. [PMID: 21833797 PMCID: PMC3228965 DOI: 10.1007/s13181-011-0173-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Organophosphate (OP) and paraquat (PQ) ingestion is a serious health problem. A common pathology behind OP or PQ poisoning is the generation of reactive oxygen species (ROS) which is known to cause ototoxicity. The aim of the study was to identify the effects of deliberate ingestion of OP or PQ on brain stem auditory-evoked potentials (BAEPs). Consecutive patients with deliberate self-poisoning with OP or PQ who were admitted to a secondary and a tertiary care hospital in the Southern province of Sri Lanka and matched controls were recruited. BAEPs were performed at 1 week (first assessment) and 6 weeks (second assessment) after the exposure. Interpeak latencies of I–III, III–V, and I–V were measured. There were 70 and 28 patients in the OP and PQ arms with the mean age of 32 ± 12 and 29 ± 12 years, respectively. There were 70 controls and their mean age was 33 ± 12 years. In OP and PQ poisoning, 53/70 and 18/28 came for the second assessment, respectively. The interpeak latency was not statistically different in the controls vs the first assessment, controls vs the second assessment, and the first vs the second assessment. There were no significant lesions in the auditory pathway in OP or PQ poisoned patients. The generation of ROS within the perilymphatic space following the ingestion of OP or PQ may not be sufficient to cause lesions in the auditory pathway. Further studies with the assessment of auditory threshold are needed.
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Campbell K, Claussen A, Meech R, Verhulst S, Fox D, Hughes L. D-methionine (D-met) significantly rescues noise-induced hearing loss: timing studies. Hear Res 2011; 282:138-44. [PMID: 21924333 DOI: 10.1016/j.heares.2011.08.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 08/12/2011] [Accepted: 08/15/2011] [Indexed: 02/06/2023]
Abstract
We have previously reported rescue from noise-induced auditory brainstem response (ABR) threshold shifts with d-methionine (d-met) administration 1 h after noise exposure. The present study investigated further d-met rescue intervals at 3, 5 and 7 h post-noise exposure. Chinchillas laniger were exposed to a 6 h 105 dB sound pressure level (dB SPL) octave band noise (OBN) and then administered d-met i.p. starting 3, 5, or 7 h after noise exposure; controls received saline i.p. immediately after noise exposure. ABR assessments were performed at baseline and on post-exposure days 1 and 21. Outer hair cell (OHC) loss was measured in cochleae obtained at sacrifice 21 days post-exposure. Administration of d-met starting at any of the delay times of 3-7 h post-noise exposure significantly reduced day 21 ABR threshold shift at 2 and 4 kHz and OHC loss at all hair cell regions measured (2, 4, 6 and 8 kHz). ABR threshold shifts in the control group at 6 and 8 kHz were only 8 and 11 dB respectively allowing little opportunity to observe protection at those 2 frequencies.
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Affiliation(s)
- Kathleen Campbell
- Department of Surgery, Division of Otolaryngology, Southern Illinois University School of Medicine, PO Box 19629, Springfield, IL 62794-9629, USA.
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Crawley BK, Keithley EM. Effects of mitochondrial mutations on hearing and cochlear pathology with age. Hear Res 2011; 280:201-8. [PMID: 21664445 DOI: 10.1016/j.heares.2011.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 05/20/2011] [Accepted: 05/20/2011] [Indexed: 02/04/2023]
Abstract
Age-related hearing loss is a multi-factorial process involving genetic and environmental factors, including exposure to noise and ototoxic agents, as well as pathological processes. Among these is the accumulation of mitochondrial DNA mutations and deletions. The creation of a transgenic mouse with a loss-of-function deletion of the nuclear gene that encodes the polymerase required to repair damaged mitochondrial DNA (PolgA) enabled evaluation of age-related cochlear pathology associated with random mitochondrial DNA deletions that accrue over the lifespan of the mouse. In comparison with their wild-type or heterozygous counterparts, animals with mutated DNA polymerase gamma developed hearing loss most rapidly. Any loss of mitochondrial DNA polymerase function however, resulted in detrimental effects, as evidenced by hearing tests and histological investigation of transgenic heterozygotes. Cochlear pathology in transgenic animals at 10 months of age included loss of neurons and clumping of surviving neurons in the apical turn of the spiral ganglion. Mitochondrial mutations in young animals, on the other hand, were protective against the development of temporary threshold shift in response to relatively low level noise exposure. This supports the idea that temporary threshold shifts are the result of an active process involving mitochondria and respiratory chain activity. Our results indicate that mitochondrial mutation and deletion can certainly contribute to the development of an aging phenotype, specifically age-related hearing loss.
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Affiliation(s)
- Brianna K Crawley
- Division of Otolaryngology-Head and Neck Surgery, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0666, USA
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Mukherjea D, Jajoo S, Sheehan K, Kaur T, Sheth S, Bunch J, Perro C, Rybak LP, Ramkumar V. NOX3 NADPH oxidase couples transient receptor potential vanilloid 1 to signal transducer and activator of transcription 1-mediated inflammation and hearing loss. Antioxid Redox Signal 2011; 14:999-1010. [PMID: 20712533 PMCID: PMC3043978 DOI: 10.1089/ars.2010.3497] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Transient receptor potential vanilloid 1 (TRPV1) is implicated in cisplatin ototoxicity. Activation of this channel by cisplatin increases reactive oxygen species generation, which contribute to loss of outer hair cells in the cochlea. Knockdown of TRPV1 by short interfering RNA protected against cisplatin ototoxicity. In this study, we examined the mechanism underlying TRPV1-mediated ototoxicity using cultured organ of Corti transformed cells (UB/OC-1) and rats. Trans-tympanic injections of capsaicin produced transient hearing loss within 24 h, which recovered by 72 h. In UB/OC-1 cells, capsaicin increased NOX3 NADPH oxidase activity and activation of signal transducer and activator of transcription 1 (STAT1). Intratympanic administration of capsaicin transiently increased STAT1 activity and expression of downstream proinflammatory molecules. Capsaicin produced a transient increase in CD14-positive inflammatory cells into the cochlea, which mimicked the temporal course of STAT1 activation but did not alter the expression of apoptotic genes or damage to outer hair cells. In addition, trans-tympanic administration of STAT1 short interfering RNA protected against capsaicin-induced hearing loss. These data suggest that activation of TRPV1 mediates temporary hearing loss by initiating an inflammatory process in the cochlea via activation of NOX3 and STAT1. Thus, these proteins represent reasonable targets for ameliorating hearing loss.
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Affiliation(s)
- Debashree Mukherjea
- Department of Pharmacology, SIU School of Medicine, Springfield, Illinois 62794-9629, USA
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Adenosine amine congener mitigates noise-induced cochlear injury. Purinergic Signal 2010; 6:273-81. [PMID: 20806018 DOI: 10.1007/s11302-010-9188-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 05/19/2010] [Indexed: 02/07/2023] Open
Abstract
Hearing loss from noise exposure is a leading occupational disease, with up to 5% of the population at risk world-wide. Here, we present a novel purine-based pharmacological intervention that can ameliorate noise-induced cochlear injury. Wistar rats were exposed to narrow-band noise (8-12 kHz, 110 dB SPL, 2-24 h) to induce cochlear damage and permanent hearing loss. The selective adenosine A(1) receptor agonist, adenosine amine congener (ADAC), was administered intraperitoneally (100 microg/kg/day) at time intervals after noise exposure. Hearing thresholds were assessed using auditory brainstem responses and the hair cell loss was evaluated by quantitative histology. Free radical damage in the organ of Corti was assessed using nitrotyrosine immunohistochemistry. The treatment with ADAC after noise exposure led to a significantly greater recovery of hearing thresholds compared with controls. These results were upheld by increased survival of sensory hair cells and reduced nitrotyrosine immunoreactivity in ADAC-treated cochlea. We propose that ADAC could be a valuable treatment for noise-induced cochlear injury in instances of both acute and extended noise exposures.
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Samson J, Wiktorek-Smagur A, Politanski P, Rajkowska E, Pawlaczyk-Luszczynska M, Dudarewicz A, Sha SH, Schacht J, Sliwinska-Kowalska M. Noise-induced time-dependent changes in oxidative stress in the mouse cochlea and attenuation by D-methionine. Neuroscience 2008; 152:146-50. [PMID: 18234425 DOI: 10.1016/j.neuroscience.2007.11.015] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 11/11/2007] [Accepted: 11/13/2007] [Indexed: 02/07/2023]
Abstract
Oxidative stress in the cochlea is considered to play an important role in noise-induced hearing loss. This study determined changes in superoxide dismutase (SOD), catalase, lipid peroxidation (LPO) and the auditory brainstem response (ABR) in the cochlea of C57BL/6 mice prior to and immediately, 1, 3, 7, 10, 14 and 21 days after noise exposure (4 kHz octave band at the intensity of 110 dB SPL for 4 h). A significant increase in SOD activity immediately and on 1st day after noise exposure, without a concomitant increase in catalase activity suggested a difference in the time dependent changes in the scavenging enzymes, which facilitates the increase in LPO observed on day 7. The ABR indicated significant noise-induced functional deficits which stabilized in 2 weeks with a permanent threshold shift (PTS) of 15 dB at both 4 kHz and 8 kHz. The antioxidant D-methionine (D-Met) reversed the noise-induced changes in LPO levels and enzyme activities. It also significantly reduced the PTS observed on the 14th day from 15 dB to 5 dB for 4 kHz. In summary, the findings indicate that time-dependent alterations in scavenging enzymes facilitate the production of reactive oxygen species and that D-met effectively attenuates noise-induced oxidative stress and the associated functional loss in the mouse cochlea.
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Affiliation(s)
- J Samson
- Nofer Institute of Occupational Medicine, 8 Teresy Street, 91-348 Lodz, Poland
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Trnovec T, Sovčíková E, Hust'ák M, Wimmerová S, Kočan A, Jurečková D, Langer P, Palkovičová L, Drobná B. Exposure to polychlorinated biphenyls and hearing impairment in children. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2008; 25:183-7. [PMID: 21783857 DOI: 10.1016/j.etap.2007.10.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The objective of this cross-sectional epidemiological study was to assess if long-term exposure to polychlorinated biphenyls (PCBs) is associated with hearing impairment. Four hundred and thirty-three children aged 8-9 years residing in an area polluted by PCBs in Eastern Slovakia were examined otoscopically, tympanometrically and by pure tone audiometry. PCB levels in their serum were determined by gas chromatography. Transient otoacoustic emissions (TEOAE) were measured in a subgroup of 161 children. The mean of the sum of PCB concentrations in serum was 528.2ng/g serum lipids (median 321ng/g serum lipids). Serum PCB concentrations were associated with an increase of hearing threshold at low frequencies and a negative correlation between serum PCBs and the amplitude of TEOAE response was observed in the uppermost tertile of children grouped with regard to serum PCBs, not related to thyroid hormone levels. It was concluded that long-term environmental exposure to PCBs is associated with subclinical but diagnosable hearing deficits.
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Affiliation(s)
- Tomáš Trnovec
- Slovak Medical University, Limbová 12, 83303 Bratislava, Slovak Republic
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Abstract
Modern research has provided new insights into the biological mechanisms of noise-induced hearing loss, and with these new insights comes hope for possible prevention or treatment. Underlying the classic set of cochlear pathologies that occur as a result of noise exposure are increased levels of reactive oxygen species (ROS) that play a significant role in noise-induced hair cell death. Both necrotic and apoptotic cell death have been identified in the cochlea. Included in the current review is a brief review of ROS, along with a description of sources of cochlear ROS generation and how ROS can damage cochlear tissue. The pathways of necrotic and apoptotic cell death are also reviewed. Interventions are discussed that target the prevention of noise-induced hair cell death: the use of antioxidants to scavenge and eliminate the damaging ROS, pharmacological interventions to limit the damage resulting from ROS, and new techniques aimed at interrupting the apoptotic biochemical cascade that results in the death of irreplaceable hair cells.
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Affiliation(s)
- Donald Henderson
- Center for Hearing and Deafness, Department of Communicative Disorders and Sciences, State University of New York at Buffalo, Buffalo, New York 14214, USA.
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Harris KC, Bielefeld E, Hu BH, Henderson D. Increased resistance to free radical damage induced by low-level sound conditioning. Hear Res 2006; 213:118-29. [PMID: 16466871 DOI: 10.1016/j.heares.2005.11.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Revised: 11/22/2005] [Accepted: 11/28/2005] [Indexed: 11/16/2022]
Abstract
Conditioning is the phenomenon where exposure to moderate-level acoustic stimuli can increase the ear's resistance to subsequent more intense sound exposures. In recent years, research has shown that conditioning increases the availability of antioxidant enzymes which presumably protects the ear from oxidative stress induced by a traumatic noise exposure [Jacono, A.A., Hu, B., Kopke, R.D., Henderson, D., Van De Water, T.R., Steinman, H.M., 1998. Changes in cochlear antioxidant enzyme activity after sound conditioning and noise exposure in the chinchilla. Hear Res 117, 31-8]. The current study was designed to assess whether the increase in endogenous antioxidants seen following conditioning could provide protection from oxidative stress induced by Paraquat, a potent generator of superoxide. Chinchillas were exposed to a conditioning noise, 500 Hz OBN at 95 dB for 6 h/day for 10 days, followed 5 days later with Paraquat application to the round window. Controls underwent the Paraquat application surgery, without prior conditioning. Evoked potential thresholds were determined prior to conditioning, at day 1, 5 and 10 during conditioning, at day 15 (5 days after conditioning), and at day 17, 19, 23, and 35 (1, 3, 7, and 20 days post-Paraquat). The conditioned animals showed reductions in permanent threshold shift and reduced inner hair cell loss relative to controls. These results reinforce the hypothesis that antioxidants are primary mediators of the conditioning effect.
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Affiliation(s)
- Kelly Carney Harris
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY 14214, USA.
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