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Buján GE, D'Alessio L, Serra HA, Guelman LR, Molina SJ. Assessment of Hippocampal-Related Behavioral Changes in Adolescent Rats of both Sexes Following Voluntary Intermittent Ethanol Intake and Noise Exposure: A Putative Underlying Mechanism and Implementation of a Non-pharmacological Preventive Strategy. Neurotox Res 2024; 42:29. [PMID: 38856796 DOI: 10.1007/s12640-024-00707-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 04/16/2024] [Accepted: 05/27/2024] [Indexed: 06/11/2024]
Abstract
Ethanol (EtOH) intake and noise exposure are particularly concerning among human adolescents because the potential to harm brain. Unfortunately, putative underlying mechanisms remain to be elucidated. Moreover, implementing non-pharmacological strategies, such as enriched environments (EE), would be pertinent in the field of neuroprotection. This study aims to explore possible underlying triggering mechanism of hippocampus-dependent behaviors in adolescent animals of both sexes following ethanol intake, noise exposure, or a combination of both, as well as the impact of EE. Adolescent Wistar rats of both sexes were subjected to an intermittent voluntary EtOH intake paradigm for one week. A subgroup of animals was exposed to white noise for two hours after the last session of EtOH intake. Some animals of both groups were housed in EE cages. Hippocampal-dependent behavioral assessment and hippocampal oxidative state evaluation were performed. Results show that different hippocampal-dependent behavioral alterations might be induced in animals of both sexes after EtOH intake and sequential noise exposure, that in some cases are sex-specific. Moreover, hippocampal oxidative imbalance seems to be one of the potential underlying mechanisms. Additionally, most behavioral and oxidative alterations were prevented by EE. These findings suggest that two frequently found environmental agents may impact behavior and oxidative pathways in both sexes in an animal model. In addition, EE resulted a partially effective neuroprotective strategy. Therefore, it could be suggested that the implementation of a non-pharmacological approach might also potentially provide neuroprotective advantages against other challenges. Finally, considering its potential for translational human benefit might be worth.
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Affiliation(s)
- G E Buján
- Facultad de Medicina, Departamento de Toxicología y Farmacología, 1ª Cátedra de Farmacología, Buenos Aires, Universidad de Buenos Aires (UBA), Paraguay 2155, piso 15, 1121, Ciudad Autónoma de Buenos Aires, Argentina
| | - L D'Alessio
- Facultad de Medicina, Departamento de Toxicología y Farmacología, 1ª Cátedra de Farmacología, Buenos Aires, Universidad de Buenos Aires (UBA), Paraguay 2155, piso 15, 1121, Ciudad Autónoma de Buenos Aires, Argentina
- Instituto de Biología Celular y Neurociencias (IBCN), Universidad de Buenos Aires (UBA)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - H A Serra
- Facultad de Medicina, Departamento de Toxicología y Farmacología, 1ª Cátedra de Farmacología, Buenos Aires, Universidad de Buenos Aires (UBA), Paraguay 2155, piso 15, 1121, Ciudad Autónoma de Buenos Aires, Argentina
| | - L R Guelman
- Facultad de Medicina, Departamento de Toxicología y Farmacología, 1ª Cátedra de Farmacología, Buenos Aires, Universidad de Buenos Aires (UBA), Paraguay 2155, piso 15, 1121, Ciudad Autónoma de Buenos Aires, Argentina.
- Centro de Estudios Farmacológicos y Botánicos (CEFyBO), Universidad de Buenos Aires (UBA)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
| | - S J Molina
- Centro de Estudios Farmacológicos y Botánicos (CEFyBO), Universidad de Buenos Aires (UBA)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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2
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Harris M, Nguyen A, Brown NJ, Picton B, Gendreau J, Bui N, Sahyouni R, Lin HW. Mild Traumatic Brain Injury and the Auditory System: An Overview of the Mechanisms, Clinical Presentations, and Current Diagnostic Modalities. J Neurotrauma 2024. [PMID: 37742111 DOI: 10.1089/neu.2023.0059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/25/2023] Open
Abstract
The acute and long-term consequences of mild traumatic brain injury (mTBI) are far reaching. Though it may often be overlooked due to the now expansive field of research dedicated to understanding the consequences of mTBI on the brain, recent work has revealed that substantial changes in the vestibulo-auditory system can also occur due to mTBI. These changes, termed "labyrinthine" or "cochlear concussion," include hearing loss, vertigo, and tinnitus that develop after mTBI in the setting of an intact bony labyrinthine capsule (as detected on imaging). In the review that follows, we focus our discussion on the effects of mTBI on the peripheral structures and pathways of the auditory and vestibular systems. Although the effects of indirect trauma (e.g., noise and blast trauma) have been well-investigated, there exists a profound need to improve our understanding of the effects of direct head injury (such as mTBI) on the auditory and vestibular systems. Our aim is to summarize the current evidentiary foundation upon which labyrinthine and/or cochlear concussion are based to shed light on the ways in which clinicians can refine the existing modalities used to diagnose and treat patients experiencing mTBI as it relates to hearing and balance.
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Affiliation(s)
- Mark Harris
- Department of Neurological Surgery, Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, Irvine, California, USA
| | - Andrew Nguyen
- University of Florida College of Medicine, Gainesville, Florida, USA
| | - Nolan J Brown
- Department of Neurological Surgery, Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, Irvine, California, USA
| | - Bryce Picton
- Department of Neurological Surgery, Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, Irvine, California, USA
| | - Julian Gendreau
- Johns Hopkins Whiting School of Engineering, Baltimore, Maryland, USA
| | - Nicholas Bui
- Loma Linda University School of Medicine, Loma Linda, California, USA
| | - Ronald Sahyouni
- Department of Neurological Surgery, University of California, San Diego, San Diego, California, USA
| | - Harrison W Lin
- Division of Neurotology and Skull Base Surgery, Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, Irvine, California, USA
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3
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Paik CB, Pei M, Oghalai JS. Review of blast noise and the auditory system. Hear Res 2022; 425:108459. [PMID: 35181171 PMCID: PMC9357863 DOI: 10.1016/j.heares.2022.108459] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 11/22/2022]
Abstract
The auditory system is particularly vulnerable to blast injury due to the ear's role as a highly sensitive pressure transducer. Over the past several decades, studies have used a variety of animal models and experimental procedures to recreate blast-induced acoustic trauma. Given the developing nature of this field and our incomplete understanding of molecular mechanisms underlying blast-related auditory disturbances, an updated discussion about these studies is warranted. Here, we comprehensively review well-established blast-related auditory pathology including tympanic membrane perforation and hair cell loss. In addition, we discuss important mechanistic studies that aim to bridge gaps in our current understanding of the molecular and microstructural events underlying blast-induced cochlear, auditory nerve, brainstem, and central auditory system damage. Key findings from the recent literature include the association between endolymphatic hydrops and cochlear synaptic loss, blast-induced neuroinflammatory markers in the peripheral and central auditory system, and therapeutic approaches targeting biochemical markers of blast injury. We conclude that blast is an extreme form of noise exposure. Blast waves produce cochlear damage that appears similar to, but more extreme than, the standard noise exposure protocols used in auditory research. However, experimental variations in studies of blast-induced acoustic trauma make it challenging to compare and interpret data across studies.
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Affiliation(s)
- Connie B Paik
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA USA
| | - Michelle Pei
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA USA
| | - John S Oghalai
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA USA.
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4
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Buján GE, D'Alessio L, Serra HA, Molina SJ, Guelman LR. Behavioral alterations induced by intermittent ethanol intake and noise exposure in adolescent rats. Eur J Neurosci 2022; 55:1756-1773. [PMID: 35342999 DOI: 10.1111/ejn.15657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 03/04/2022] [Accepted: 03/22/2022] [Indexed: 11/27/2022]
Abstract
Alcohol intake and exposure to noise are common activities of human adolescents performed in entertainment contexts worldwide that can induce behavioral disturbances. Therefore, the aim of the present work was to investigate in an experimental model of adolescent animals whether noise exposure and intermittent ethanol intake, when present individually or sequentially, might be able to modify different behaviors. Adolescent Wistar rats of both sexes were subjected to voluntary intermittent ethanol intake for 1 week followed by exposure to noise for 2 h and tested in a battery of behavioral tasks. Data show that males exposed to noise experienced a deficit in associative memory (AM), increase in anxiety-like behaviors (ALB) and altered reaction to novelty (RN) when compared with sham animals, whereas females also showed an increase in risk assessment behaviors (RAB) and a decrease in exploratory activity (EA). In contrast, ethanol intake induced an increase in RAB and RN in males and females, whereas females also showed a deficit in AM and EA as well as an increase in ALB. When ethanol was ingested before noise exposure, most parameters were counteracted both in male and females, but differed among sexes. In consequence, it could be hypothesized that an environmental acute stressor like noise might trigger a behavioral counteracting induced by a previous repeated exposure to a chemical agent such as ethanol, leading to a compensation of a non-adaptive behavior and reaching a better adjustment to the environment.
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Affiliation(s)
- Gustavo Ezequiel Buján
- Universidad de Buenos Aires. Facultad de Medicina. 1ª Cátedra de Farmacología, Buenos Aires, Argentina
| | - Luciana D'Alessio
- Universidad de Buenos Aires. Facultad de Medicina. 1ª Cátedra de Farmacología, Buenos Aires, Argentina.,Universidad de Buenos Aires. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología Celular y Neurociencias (IBCN, UBA-CONICET). Facultad de Medicina, Buenos Aires, Argentina
| | - Héctor Alejandro Serra
- Universidad de Buenos Aires. Facultad de Medicina. 1ª Cátedra de Farmacología, Buenos Aires, Argentina
| | - Sonia Jazmín Molina
- Universidad de Buenos Aires. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Estudios Farmacológicos y Botánicos (CEFyBO, UBA-CONICET). Facultad de Medicina, Buenos Aires, Argentina
| | - Laura Ruth Guelman
- Universidad de Buenos Aires. Facultad de Medicina. 1ª Cátedra de Farmacología, Buenos Aires, Argentina.,Universidad de Buenos Aires. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Estudios Farmacológicos y Botánicos (CEFyBO, UBA-CONICET). Facultad de Medicina, Buenos Aires, Argentina
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5
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Xu FL, Cheng Y, Yan W. Up-regulation of autophagy and apoptosis of cochlear hair cells in mouse models for deafness. Arch Med Sci 2021; 17:535-541. [PMID: 33747288 PMCID: PMC7959062 DOI: 10.5114/aoms.2018.75348] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/24/2017] [Indexed: 12/20/2022] Open
Abstract
INTRODUCTION Hearing loss is one of the most common sensory disorders. Recent findings have shown that the apoptotic program and autophagy are related to hearing loss. The aim of the study was to explore the effects of noise and cisplatin exposure on apoptosis and autophagy in the hair cells of the cochleae. MATERIAL AND METHODS C57BL/6 mice were randomly divided into 3 groups (n = 10 for each): the control group, the noise model group and the cisplatin model group. Auditory brainstem response (ABR) measurements were used to detect the hearing thresholds. TUNEL assay was used to evaluate cell apoptosis. Western blot and immunofluorescence were performed to examine the apoptosis- and autophagy-related proteins. RESULTS The mice exhibited substantial hearing loss after noise and cisplatin exposure. Additionally, more TUNEL positive cells were observed in the mice after noise and cisplatin exposure compared with the control group. Moreover, the protein expression levels of Beclin-1, LC3-II, Bax and cleaved caspase-3 were significantly increased, while the expression of Bcl-2 was notably decreased in the cochlea after noise (p = 0.0278, 0.0075, 0.0142, 0.0158, 0.0131 respectively) and cisplatin (p = 0.0220, 0.0075, 0.0024, 0.0161, 0.0452 respectively) exposure compared with the control group. Besides, the ratio of LC3-II/LC3-I was substantially higher in the mice treated by cisplatin (p = 0.0046) and noise (p = 0.0220) compared with the control group. CONCLUSIONS Our findings demonstrated for the first time that noise and cisplatin exposure promoted apoptosis and autophagy in the hair cells of the cochleae. This study provides new insights into the mechanisms of noise- or cisplatin-induced hearing loss.
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Affiliation(s)
- Fei-Long Xu
- Department of Otology, The First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Yanjie Cheng
- Department of Otology, The First Affiliated Hospital of Zhengzhou University, Henan, China
| | - Wenya Yan
- Department of Otology, The First Affiliated Hospital of Zhengzhou University, Henan, China
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6
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Bielefeld EC, Harrison RT, Riley DeBacker J. Pharmaceutical otoprotection strategies to prevent impulse noise-induced hearing loss. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:3790. [PMID: 31795721 DOI: 10.1121/1.5132285] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
One of the ongoing challenges for hearing researchers is successful protection of the ear from noise injury. For decades, the most effective methods have been based on modifying the acoustic properties of the noise, either by reducing noise output from various sources, interfering in the acoustic exposure path with environmental controls, or altering the noise dose for the individual with personal hearing protection devices. Because of the inefficiencies of some of the acoustic modification procedures, pharmaceutical otoprotection is targeted at making the cochlea less susceptible to injury. Short-duration, high-level impulse noises, typically caused by small-scale explosions, cause different sets of injuries in the ear than long-duration, low-variance noise exposures. Therefore, the expectation is that the ears exposed to impulse noise may need different pharmaceutical interventions, both in type of compounds used and the time course of administration of the compounds. The current review discusses four different classes of compounds that have been tested as impulse noise otoprotectants. In the process of describing those experiments, particular emphasis is placed on the acoustic properties of the impulses used, with the goal of providing context for evaluating the relevance of these different models to human impulse noise-induced hearing loss.
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Affiliation(s)
- Eric C Bielefeld
- Department of Speech and Hearing Science, The Ohio State University, 110 Pressey Hall, 1070 Carmack Road, Columbus, Ohio 43220, USA
| | - Ryan T Harrison
- Department of Speech and Hearing Science, The Ohio State University, 110 Pressey Hall, 1070 Carmack Road, Columbus, Ohio 43220, USA
| | - J Riley DeBacker
- Department of Speech and Hearing Science, The Ohio State University, 110 Pressey Hall, 1070 Carmack Road, Columbus, Ohio 43220, USA
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7
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Kim S, Lee DG. Role of calcium in reactive oxygen species-induced apoptosis in Candida albicans: an antifungal mechanism of antimicrobial peptide, PMAP-23. Free Radic Res 2019; 53:8-17. [DOI: 10.1080/10715762.2018.1511052] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Suhyun Kim
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
| | - Dong Gun Lee
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
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8
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Intracochlear drug delivery: Fluorescent tracer evaluation for quantification of distribution in the cochlear partition. Eur J Pharm Sci 2019; 126:49-58. [PMID: 30195649 DOI: 10.1016/j.ejps.2018.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 08/20/2018] [Accepted: 09/06/2018] [Indexed: 11/23/2022]
Abstract
Measurement of drug distribution in the inner ear has important roles in the design of local delivery methods, such as direct, intracochlear delivery, and in assessment of emerging drug candidates in preclinical animal models. Sampling methods have been used in the past to measure drug concentrations in the cochlear fluids, but these methods provide no direct information about drug distribution in the cochlear tissues. In this work, we evaluated four fluorescent markers that simulate drug distribution in the organ of Corti after intracochlear delivery to the cochlea's scala tympani compartment. Our hypothesis is that ultimately, a cocktail comprising several fluorescent drug surrogates or fluorescently-tagged drugs, each with differing distribution, spreading, and clearance behavior, can be used to evaluate both transient and cumulative drug distributions associated with different delivery techniques. In this study, FITC-dextran, Qtracker™ 655, gentamicin Texas-Red, and FM 1-43 FX were each evaluated as candidate markers by direct intracochlear infusion into guinea-pig cochleae. Distribution of the markers was measured using fluorescence confocal microscopy imaging of cochlear whole mount dissections from animals sacrificed 3 h after the tracer-infusion. For all four tracers, strong fluorescence was observed in the tissue sections near the base, but only Qtracker™-655, gentamicin Texas-Red (GTTR) and FM 1-43 FX exhibited any specificity in labelling of the sensory hair cells. Therefore, these substances represent leading candidates for the quantification drug distribution achieved by different delivery approaches to the scala tympani.
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9
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Miceli M, Molina SJ, Forcada A, Acosta GB, Guelman LR. Voluntary alcohol intake after noise exposure in adolescent rats: Hippocampal-related behavioral alterations. Brain Res 2017; 1679:10-18. [PMID: 29113737 DOI: 10.1016/j.brainres.2017.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 10/25/2017] [Accepted: 11/01/2017] [Indexed: 11/16/2022]
Abstract
Different physical or chemical agents, such as noise or alcohol, can induce diverse behavioral and biochemical alterations. Considering the high probability of young people to undergo consecutive or simultaneous exposures, the aim of the present work was to investigate in an animal model if noise exposure at early adolescence could induce hippocampal-related behavioral changes that might be modified after alcohol intake. Male Wistar rats (28-days-old) were exposed to noise (95-97 dB, 2 h). Afterwards, animals were allowed to voluntarily drink alcohol (10% ethanol in tap water) for three consecutive days, using the two-bottle free choice paradigm. After that, hippocampal-related memory and anxiety-like behavior tests were performed. Results show that whereas noise-exposed rats presented deficits in habituation memory, those who drank alcohol exhibited impairments in associative memory and anxiety-like behaviors. In contrast, exposure to noise followed by alcohol intake showed increases in exploratory and locomotor activities as well as in anxiety-like behaviors, unlike what was observed using each agent separately. Finally, lower levels of alcohol intake were measured in these animals when compared with those that drank alcohol and were not exposed to noise. Present findings demonstrate that exposure to physical and chemical challenges during early adolescence might induce behavioral alterations that could differ depending on the schedule used, suggesting a high vulnerability of rat developing brain to these socially relevant agents.
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Affiliation(s)
- M Miceli
- Universidad de Buenos Aires, Facultad de Medicina, 1ª Cátedra de Farmacología, Buenos Aires, Argentina
| | - S J Molina
- Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Centro de Estudios Farmacológicos y Botánicos (CEFyBO, UBA-CONICET), Buenos Aires, Argentina
| | - A Forcada
- Universidad de Buenos Aires, Facultad de Medicina, 1ª Cátedra de Farmacología, Buenos Aires, Argentina
| | - G B Acosta
- Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Instituto de Investigaciones Farmacológicas (ININFA, UBA-CONICET), Buenos Aires, Argentina
| | - L R Guelman
- Universidad de Buenos Aires, Facultad de Medicina, 1ª Cátedra de Farmacología, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Centro de Estudios Farmacológicos y Botánicos (CEFyBO, UBA-CONICET), Buenos Aires, Argentina.
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10
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de Iriarte Rodríguez R, Magariños M, Pfeiffer V, Rapp UR, Varela-Nieto I. C-Raf deficiency leads to hearing loss and increased noise susceptibility. Cell Mol Life Sci 2015; 72:3983-98. [PMID: 25975225 PMCID: PMC4575698 DOI: 10.1007/s00018-015-1919-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 04/21/2015] [Accepted: 04/27/2015] [Indexed: 12/20/2022]
Abstract
The family of RAF kinases transduces extracellular information to the nucleus, and their activation is crucial for cellular regulation on many levels, ranging from embryonic development to carcinogenesis. B-RAF and C-RAF modulate neurogenesis and neuritogenesis during chicken inner ear development. C-RAF deficiency in humans is associated with deafness in the rare genetic insulin-like growth factor 1 (IGF-1), Noonan and Leopard syndromes. In this study, we show that RAF kinases are expressed in the developing inner ear and in adult mouse cochlea. A homozygous C-Raf deletion in mice caused profound deafness with no evident cellular aberrations except for a remarkable reduction of the K+ channel Kir4.1 expression, a trait that suffices as a cause of deafness. To explore the role of C-Raf in cellular protection and repair, heterozygous C-Raf+/− mice were exposed to noise. A reduced C-RAF level negatively affected hearing preservation in response to noise through mechanisms involving the activation of JNK and an exacerbated apoptotic response. Taken together, these results strongly support a role for C-RAF in hearing protection.
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Affiliation(s)
- Rocío de Iriarte Rodríguez
- Instituto de Investigaciones Biomédicas "Alberto Sols", CSIC-UAM, Arturo Duperier 4, 28029, Madrid, Spain.,Centre for Biomedical Network Research (CIBERER), Institute of Health Carlos III (ISCIII), Madrid, Spain
| | - Marta Magariños
- Instituto de Investigaciones Biomédicas "Alberto Sols", CSIC-UAM, Arturo Duperier 4, 28029, Madrid, Spain. .,Centre for Biomedical Network Research (CIBERER), Institute of Health Carlos III (ISCIII), Madrid, Spain. .,Departamento de Biología, Universidad Autónoma de Madrid, Darwin 2, 28049, Madrid, Spain.
| | - Verena Pfeiffer
- Institute for Medical Radiation and Cell Research (MSZ), University of Würzburg, Versbacher Strasse 5, 97078, Würzburg, Germany.,Institute for Anatomy and Cell Biology, University of Würzburg, Koellikerstraße 6, 97070, Würzburg, Germany
| | - Ulf R Rapp
- Institute for Medical Radiation and Cell Research (MSZ), University of Würzburg, Versbacher Strasse 5, 97078, Würzburg, Germany.,Molecular Mechanisms of Lung Cancer, Max Planck Institute for Heart and Lung Research, Parkstr. 1, 61231, Bad Nauheim, Germany
| | - Isabel Varela-Nieto
- Instituto de Investigaciones Biomédicas "Alberto Sols", CSIC-UAM, Arturo Duperier 4, 28029, Madrid, Spain.,Centre for Biomedical Network Research (CIBERER), Institute of Health Carlos III (ISCIII), Madrid, Spain.,Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain
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11
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Abstract
Mechanisms that lead to the death of hair cells are reviewed. Exposure to noise, the use of ototoxic drugs that damage the cochlea and old age are accompanied by hair cell death. Outer hair cells are often more susceptible than inner hair cells, partly because of an intrinsically greater susceptibility; high frequency cells are also more vulnerable. A common factor in hair cell loss following age-related changes and exposure to ototoxic drugs or high noise levels is the generation of reactive oxygen species, which can trigger intrinsic apoptosis (the mitochondrial pathway). However, hair cell death is sometimes produced via an extracellular signal pathway triggering extrinsic apoptosis. Necrosis and necroptosis also play a role and, in various situations in which cochlear damage occurs, a balance exists between these possible routes of cell death, with no one mechanism being exclusively activated. Finally, the numerous studies on these mechanisms of hair cell death have led to the identification of many potential therapeutic agents, some of which have been used to attempt to treat people exposed to damaging events, although clinical trials are not yet conclusive. Continued work in this area is likely to lead to clinical treatments that could be used to prevent or ameliorate hearing loss.
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Affiliation(s)
- David N Furness
- School of Life Sciences, Keele University, Keele, Staffordshire, ST5 5BG, UK,
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12
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Age-related hearing loss in Mn-SOD heterozygous knockout mice. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:325702. [PMID: 23936608 PMCID: PMC3710654 DOI: 10.1155/2013/325702] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Accepted: 06/02/2013] [Indexed: 01/07/2023]
Abstract
Age-related hearing loss (AHL) reduces the quality of life for many elderly individuals. Manganese superoxide dismutase (Mn-SOD), one of the antioxidant enzymes acting within the mitochondria, plays a crucial role in scavenging reactive oxygen species (ROS). To determine whether reduction in Mn-SOD accelerates AHL, we evaluated auditory function in Mn-SOD heterozygous knockout (HET) mice and their littermate wild-type (WT) C57BL/6 mice by means of auditory brainstem response (ABR). Mean ABR thresholds were significantly increased at 16 months when compared to those at 4 months in both WT and HET mice, but they did not significantly differ between them at either age. The extent of hair cell loss, spiral ganglion cell density, and thickness of the stria vascularis also did not differ between WT and HET mice at either age. At 16 months, immunoreactivity of 8-hydroxydeoxyguanosine was significantly greater in the SGC and SV in HET mice compared to WT mice, but that of 4-hydroxynonenal did not differ between them. These findings suggest that, although decrease of Mn-SOD by half may increase oxidative stress in the cochlea to some extent, it may not be sufficient to accelerate age-related cochlear damage under physiological aging process.
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13
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Transcriptome characterization by RNA-Seq reveals the involvement of the complement components in noise-traumatized rat cochleae. Neuroscience 2013; 248:1-16. [PMID: 23727008 DOI: 10.1016/j.neuroscience.2013.05.038] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 05/16/2013] [Accepted: 05/21/2013] [Indexed: 12/12/2022]
Abstract
Acoustic trauma, a leading cause of sensorineural hearing loss in adults, induces a complex degenerative process in the cochlea. Although previous investigations have identified multiple stress pathways, a comprehensive analysis of cochlear responses to acoustic injury is still lacking. In the current study, we used the next-generation RNA-sequencing (RNA-Seq) technique to sequence the whole transcriptome of the normal and noise-traumatized cochlear sensory epithelia (CSE). CSE tissues were collected from rat inner ears 1d after the rats were exposed to a 120-dB (sound pressure level) noise for 2 h. The RNA-Seq generated over 176 million sequence reads for the normal CSE and over 164 million reads for the noise-traumatized CSE. Alignment of these sequences with the rat Rn4 genome revealed the expression of over 17,000 gene transcripts in the CSE, over 2000 of which were exclusively expressed in either the normal or noise-traumatized CSE. Seventy-eight gene transcripts were differentially expressed (70 upregulated and 8 downregulated) after acoustic trauma. Many of the differentially expressed genes are related to the innate immune system. Further expression analyses using quantitative real time PCR confirmed the constitutive expression of multiple complement genes in the normal organ of Corti and the changes in the expression levels of the complement factor I (Cfi) and complement component 1, s subcomponent (C1s) after acoustic trauma. Moreover, protein expression analysis revealed strong expression of Cfi and C1s proteins in the organ of Corti. Importantly, these proteins exhibited expression changes following acoustic trauma. Collectively, the results of the current investigation suggest the involvement of the complement components in cochlear responses to acoustic trauma.
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Uran S, Aon-Bertolino M, Caceres L, Capani F, Guelman L. Rat hippocampal alterations could underlie behavioral abnormalities induced by exposure to moderate noise levels. Brain Res 2012; 1471:1-12. [DOI: 10.1016/j.brainres.2012.06.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 06/15/2012] [Accepted: 06/15/2012] [Indexed: 12/21/2022]
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Zheng G, Hu BH. Cell-cell junctions: a target of acoustic overstimulation in the sensory epithelium of the cochlea. BMC Neurosci 2012; 13:71. [PMID: 22712683 PMCID: PMC3407512 DOI: 10.1186/1471-2202-13-71] [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] [Received: 03/23/2012] [Accepted: 06/19/2012] [Indexed: 12/20/2022] Open
Abstract
Background Exposure to intense noise causes the excessive movement of the organ of Corti, stretching the organ and compromising sensory cell functions. We recently revealed changes in the transcriptional expression of multiple adhesion-related genes during the acute phases of cochlear damage, suggesting that the disruption of cell-cell junctions is an early event in the process of cochlear pathogenesis. However, the functional state of cell junctions in the sensory epithelium is not clear. Here, we employed graded dextran-FITC, a macromolecule tracer that is impermeable to the organ of Corti under physiological conditions, to evaluate the barrier function of cell junctions in normal and noise-traumatized cochlear sensory epithelia. Results Exposure to an impulse noise of 155 dB (peak sound pressure level) caused a site-specific disruption in the intercellular junctions within the sensory epithelium of the chinchilla cochlea. The most vulnerable sites were the junctions among the Hensen cells and between the Hensen and Deiters cells within the outer zone of the sensory epithelium. The junction clefts that formed in the reticular lamina were permeable to 40 and 500 but not 2,000 kDa dextran-FITC macromolecules. Moreover, this study showed that the interruption of junction integrity occurred in the reticular lamina and also in the basilar membrane, a site that had been considered to be resistant to acoustic injury. Finally, our study revealed a general spatial correlation between the site of sensory cell damage and the site of junction disruption. However, the two events lacked a strict one-to-one correlation, suggesting that the disruption of cell-cell junctions is a contributing, but not the sole, factor for initiating acute sensory cell death. Conclusions Impulse noise causes the functional disruption of intercellular junctions in the sensory epithelium of the chinchilla cochlea. This disruption occurs at an early phase of cochlear damage. Understanding the role of this disruption in cochlear pathogenesis will require future study.
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Affiliation(s)
- Guiliang Zheng
- Center for Hearing and Deafness, State University of New York at Buffalo, Buffalo, USA
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Kight CR, Swaddle JP. How and why environmental noise impacts animals: an integrative, mechanistic review. Ecol Lett 2011; 14:1052-61. [PMID: 21806743 DOI: 10.1111/j.1461-0248.2011.01664.x] [Citation(s) in RCA: 283] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The scope and magnitude of anthropogenic noise pollution are often much greater than those of natural noise and are predicted to have an array of deleterious effects on wildlife. Recent work on this topic has focused mainly on behavioural responses of animals exposed to noise. Here, by outlining the effects of acoustic stimuli on animal physiology, development, neural function and genetic effects, we advocate the use of a more mechanistic approach in anthropogenic environments. Specifically, we summarise evidence and hypotheses from research on laboratory, domestic and free-living animals exposed to biotic and abiotic stimuli, studied both observationally and experimentally. We hope that this molecular- and cellular-focused literature, which examines the effects of noise on the neuroendocrine system, reproduction and development, metabolism, cardiovascular health, cognition and sleep, audition, the immune system, and DNA integrity and gene expression, will help researchers better understand results of previous work, as well as identify new avenues of future research in anthropogenic environments. Furthermore, given the interconnectedness of these physiological, cellular and genetic processes, and their effects on behaviour and fitness, we suggest that much can be learned from a more integrative framework of how and why animals are affected by environmental noise.
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Affiliation(s)
- Caitlin R Kight
- Institute for Integrated Bird Behavior Studies, Biology Department, College of William and Mary, Williamsburg, VA, USA.
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