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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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2
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Yu W, Zong S, Du P, Zhou P, Li H, Wang E, Xiao H. Role of the Stria Vascularis in the Pathogenesis of Sensorineural Hearing Loss: A Narrative Review. Front Neurosci 2021; 15:774585. [PMID: 34867173 PMCID: PMC8640081 DOI: 10.3389/fnins.2021.774585] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 10/28/2021] [Indexed: 12/20/2022] Open
Abstract
Sensorineural hearing loss is a common sensory impairment in humans caused by abnormalities in the inner ear. The stria vascularis is regarded as a major cochlear structure that can independently degenerate and influence the degree of hearing loss. This review summarizes the current literature on the role of the stria vascularis in the pathogenesis of sensorineural hearing loss resulting from different etiologies, focusing on both molecular events and signaling pathways, and further attempts to explore the underlying mechanisms at the cellular and molecular biological levels. In addition, the deficiencies and limitations of this field are discussed. With the rapid progress in scientific technology, new opportunities are arising to fully understand the role of the stria vascularis in the pathogenesis of sensorineural hearing loss, which, in the future, will hopefully lead to the prevention, early diagnosis, and improved treatment of sensorineural hearing loss.
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Affiliation(s)
- Wenting Yu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shimin Zong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Peiyu Du
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Peng Zhou
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hejie Li
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Enhao Wang
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hongjun Xiao
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Ye R, Sun L, Peng J, Wu A, Chen X, Wen L, Bai C, Chen G. Design, Synthesis, and Biological Evaluation of Dexamethasone-Salvianolic Acid B Conjugates and Nanodrug Delivery against Cisplatin-Induced Hearing Loss. J Med Chem 2021; 64:3115-3130. [PMID: 33666428 DOI: 10.1021/acs.jmedchem.0c01916] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cisplatin (CDDP) is an extensively used chemotherapeutic agent but has a high incidence of severe ototoxicity. Although a few molecules have entered clinical trials, none have been approved to prevent or treat CDDP-induced hearing loss by the Food and Drug Administration. In this study, an amphiphilic drug-drug conjugate was synthesized by covalently linking dexamethasone (DEX) and salvianolic acid B (SAL) through an ester or amide bond. The conjugates could self-assemble into nanoparticles (NPs) with ultrahigh drug loading capacity and favorable stability. Compared with DEX, SAL, or their physical mixture at the same concentrations, both conjugates and NPs showed enhanced otoprotection in vitro and in vivo. More importantly, the conjugates and NPs almost completely restored hearing in a guinea pig model with good biocompatibility. Immunohistochemical analyses suggested that conjugates and NPs activated the glucocorticoid receptor, which may work as one of the major mechanisms for their protective effects.
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Affiliation(s)
- Ruiqin Ye
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Lifang Sun
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Jinghui Peng
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Aixin Wu
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Xiaozhu Chen
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Lu Wen
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Chuan Bai
- Institute of Human Virology, Sun Yat-sen University, Guangzhou 510080, China
| | - Gang Chen
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China.,Guangdong Provincial Key Laboratory of Advanced Drug Delivery, Guangdong Pharmaceutical University, Guangzhou 510006, China.,Guangdong Provincial Engineering Center of Topical Precise Drug Delivery System, Guangdong Pharmaceutical University, Guangzhou 510006, China
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4
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Heinrich UR, Schmidtmann I, Meuser R, Ernst BP, Wünsch D, Siemer S, Gribko A, Stauber RH, Strieth S. Early Alterations of Endothelial Nitric Oxide Synthase Expression Patterns in the Guinea Pig Cochlea After Noise Exposure. J Histochem Cytochem 2019; 67:845-855. [PMID: 31510846 DOI: 10.1369/0022155419876644] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Constitutively expressed endothelial nitric oxide synthase (eNOS) is supposed to play a role in noise-induced nitric oxide (NO)-production. It is commonly known that intense noise exposure results in inducible NOS (iNOS) expression and increased NO-production, but knowledge about a contribution of the eNOS isoform is still lacking. Effects of noise exposure on eNOS immunolabeling were determined in male guinea pigs (n=24). For light microscopic analysis, 11 animals were exposed to 90 dB for 1 hr and 6 animals were used as controls. After exposure, eNOS immunostaining was performed on paraffin sections, and the staining intensities were quantified for 4 cochlear regions. For electron microscopic analysis, 2 animals were exposed for 2 hr to 90 dB and 5 animals were used as controls. The intensity of eNOS immunolabeling was found to be already comprehensively increased 1 hr after noise exposure to 90 dB. At the ultrastructural level, a clear increase in eNOS immunolabeling was found in microtubules-rich areas of cochlear cuticular structures. Hence, our findings indicate that the reticular lamina forming the endolymph-perilymph barrier at the apical side of the organ of Corti is involved in a fast intrinsic otoprotective mechanism of the cochlea.
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Affiliation(s)
- Ulf R Heinrich
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| | - Irene Schmidtmann
- Institute for Medical Biostatistics, Epidemiology and Informatics (IMBEI), University Medical Center Mainz, Mainz, Germany
| | - Regina Meuser
- Institute for Medical Biostatistics, Epidemiology and Informatics (IMBEI), University Medical Center Mainz, Mainz, Germany
| | - Benjamin P Ernst
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| | - Desiree Wünsch
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| | - Svenja Siemer
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| | - Alena Gribko
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| | - Roland H Stauber
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| | - Sebastian Strieth
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
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5
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Alvarado JC, Fuentes-Santamaría V, Gabaldón-Ull MC, Jareño-Flores T, Miller JM, Juiz JM. Noise-Induced "Toughening" Effect in Wistar Rats: Enhanced Auditory Brainstem Responses Are Related to Calretinin and Nitric Oxide Synthase Upregulation. Front Neuroanat 2016; 10:19. [PMID: 27065815 PMCID: PMC4815363 DOI: 10.3389/fnana.2016.00019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/15/2016] [Indexed: 01/07/2023] Open
Abstract
An appropriate conditioning noise exposure may reduce a subsequent noise-induced threshold shift. Although this "toughening" effect helps to protect the auditory system from a subsequent traumatic noise exposure, the mechanisms that regulate this protective process are not fully understood yet. Accordingly, the goal of the present study was to characterize physiological processes associated with "toughening" and to determine their relationship to metabolic changes in the cochlea and cochlear nucleus (CN). Auditory brainstem responses (ABR) were evaluated in Wistar rats before and after exposures to a sound conditioning protocol consisting of a broad-band white noise of 118 dB SPL for 1 h every 72 h, four times. After the last ABR evaluation, animals were perfused and their cochleae and brains removed and processed for the activity markers calretinin (CR) and neuronal nitric oxide synthase (nNOS). Toughening was demonstrated by a progressively faster recovery of the threshold shift, as well as wave amplitudes and latencies over time. Immunostaining revealed an increase in CR and nNOS levels in the spiral ganglion, spiral ligament, and CN in noise-conditioned rats. Overall, these results suggest that the protective mechanisms of the auditory toughening effect initiate in the cochlea and extend to the central auditory system. Such phenomenon might be in part related to an interplay between CR and nitric oxide signaling pathways, and involve an increased cytosolic calcium buffering capacity induced by the noise conditioning protocol.
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Affiliation(s)
- Juan C Alvarado
- Instituto de Investigación en Discapacidades NeurológicasAlbacete, Spain; Facultad de Medicina, Universidad de Castilla-La ManchaAlbacete, Spain
| | - Verónica Fuentes-Santamaría
- Instituto de Investigación en Discapacidades NeurológicasAlbacete, Spain; Facultad de Medicina, Universidad de Castilla-La ManchaAlbacete, Spain
| | - María C Gabaldón-Ull
- Instituto de Investigación en Discapacidades NeurológicasAlbacete, Spain; Facultad de Medicina, Universidad de Castilla-La ManchaAlbacete, Spain
| | - Tania Jareño-Flores
- Grupo de Neurobiología de la Audición, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid Madrid, Spain
| | - Josef M Miller
- Center for Hearing and Communication Research and Department of Clinical Neuroscience, Karolinska InstitutetStockholm, Sweden; Kresge Hearing Research Institute, University of MichiganAnn Arbor, MI, USA
| | - José M Juiz
- Instituto de Investigación en Discapacidades NeurológicasAlbacete, Spain; Facultad de Medicina, Universidad de Castilla-La ManchaAlbacete, Spain
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6
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Heinrich UR, Strieth S, Schmidtmann I, Stauber R, Helling K. Dexamethasone prevents hearing loss by restoring glucocorticoid receptor expression in the guinea pig cochlea. Laryngoscope 2015; 126:E29-34. [DOI: 10.1002/lary.25345] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2015] [Indexed: 12/20/2022]
Affiliation(s)
- Ulf-Rüdiger Heinrich
- Department of Otorhinolaryngology, Head and Neck Surgery; University Medical Center of the Johannes Gutenberg-University; Mainz Germany
| | - Sebastian Strieth
- Department of Otorhinolaryngology, Head and Neck Surgery; University Medical Center of the Johannes Gutenberg-University; Mainz Germany
| | - Irene Schmidtmann
- Institute for Medical Statistics, Epidemiology and Informatics; University Medical Center of the Johannes Gutenberg-University; Mainz Germany
| | - Roland Stauber
- Department of Otorhinolaryngology, Head and Neck Surgery; University Medical Center of the Johannes Gutenberg-University; Mainz Germany
| | - Kai Helling
- Department of Otorhinolaryngology, Head and Neck Surgery; University Medical Center of the Johannes Gutenberg-University; Mainz Germany
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7
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Yonamine FK, Onishi ET, Mouro MG, Higa EMS, Cruz OLM. Nitric oxide levels in cochlear fluids of guinea pig. Acta Cir Bras 2013; 28:397-402. [PMID: 23702944 DOI: 10.1590/s0102-86502013000500013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 04/14/2013] [Indexed: 11/22/2022] Open
Abstract
PURPOSE To describe a technique to obtain guinea pigs cochlear fluids and measure nitric oxide (NO) concentration. METHODS Six guinea pigs were used and sacrificed. The cochlear fluids collected for measurement of NO, performed by chemiluminescence (NOA 280). RESULTS Through the chemiluminescence was possible to analyze the concentration of NO in cochlear fluids obtained. Average levels of nitric oxide from guinea pigs was 12.55 µM. CONCLUSION It is possible to obtain nitric oxide cochlear fluids, with this technique and nitric oxide concentration measure by chemiluminescence, a quantitative and more precise method.
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Affiliation(s)
- Fernando Kaoru Yonamine
- Department of Otorhinolaryngology, Head and Neck Surgery, Federal University of Sao Paulo, Brazil.
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8
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Li ML, Lee LC, Cheng YR, Kuo CH, Chou YF, Chen YS, Yao CM, Chen PR, Hsu CJ, Song YL, Lee CF. A novel aerosol-mediated drug delivery system for inner ear therapy: intratympanic aerosol methylprednisolone can attenuate acoustic trauma. IEEE Trans Biomed Eng 2013; 60:2450-60. [PMID: 23613018 DOI: 10.1109/tbme.2013.2258154] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We developed a novel aerosol-mediated drug delivery system for inner ear therapy by using a silicon-based multiple-Fourier horn nozzle. Intratympanic aerosol (ITA) methylprednisolone (MP) delivery can protect hearing after acoustic trauma. The highest concentration of MP (38.9 ± 5.47 ppm) appeared at 2 h and declined rapidly within 10 h. The concentrations of MP remained at a relatively low level for more than 10 h. Compared to the baseline, the auditory brainstem response (ABR) thresholds shifted markedly at 1 h after noise exposure in all groups (p < 0.05). From the cochleograms, it can be noted that the main lesions encompassed the 2-20 kHz frequency range. Significant differences ( ) were observed for the range between 5 and 8 kHz in the cell loss of outer hair cells (OHCs). The losses for IHCs were lower than for OHCs. The MP movement in the middle ear was simulated by a convection diffusion equation with a relaxation time. The relaxation time was 0.5 h, and the concentration threshold of MP on the round window membrane (RWM) in the middle ear (C T) was 8900 ppm. Using the unit hydrograph (UH) method, we obtained a proper boundary concentration on the RWM at the cochlea, which resulted in a well-fit concentration. Finally, a linking mechanism between the middle ear and the cochlea was established by the RWM. The adjustable permeability and concentration threshold provide the flexibility to match the peak times and peak values of the concentration on the RWM in the middle ear and the cochlea.
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Affiliation(s)
- Ming-Lung Li
- National Center for High-Performance Computing and National Applied Research laboratories, Hsinchu 30076, Taiwan.
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9
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Rewerska A, Pawelczyk M, Rajkowska E, Politanski P, Sliwinska-Kowalska M. Evaluating D-methionine dose to attenuate oxidative stress-mediated hearing loss following overexposure to noise. Eur Arch Otorhinolaryngol 2012. [PMID: 23179931 PMCID: PMC3608867 DOI: 10.1007/s00405-012-2265-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Noise exposure causes an excessive reactive oxygen species (ROS) generation as an unwanted byproduct of high metabolic activity. Oxidative stress and antioxidative protective mechanisms have been therefore proposed as the most interesting issues in the development of noise-induced hearing loss. The aim of this study was to examine changes in superoxide dismutase (SOD), catalase (CAT) and the auditory brainstem response (ABR) in the cochlea of C57BL/6 mice 1, 7 and 14 days after exposure to 4 kHz octave band noise at the intensity of 110 dB SPL for 8 h. The evaluation of three d-methionine (d-met) doses (100, 200 and 400 mg/kg) has been performed in order to choose an optimal concentration displaying most effectively its antioxidant and thereby otoprotective functions. Administering d-met at the dose of 400 mg/kg resulted in a significant decrease in threshold shift (TS) independently of the evaluation time after exposure to noise. SOD activity was strongly supported by the same concentration (400 mg/kg) of d-met. This effect was seen not shortly, but 7 and 14 days after exposure to noise. CAT activity was induced only by noise and it reached the peak levels 7 days after exposure. d-Met at the doses of 200 and 400 mg/kg significantly decreased noise-induced changes in CAT activity. The findings of this study indicate that the protective effect depends on the concentration of d-met and can be fully expressed only when the drug is administered in the dose 400 mg/kg.
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Affiliation(s)
- A. Rewerska
- Department of Audiology and Phoniatrics, Nofer Institute of Occupational Medicine, Lodz, Poland
| | - M. Pawelczyk
- Department of Audiology and Phoniatrics, Nofer Institute of Occupational Medicine, Lodz, Poland
| | - E. Rajkowska
- Department of Audiology and Phoniatrics, Nofer Institute of Occupational Medicine, Lodz, Poland
| | - P. Politanski
- Electromagnetic Hazards Laboratory, Nofer Institute of Occupational Medicine, Lodz, Poland
| | - M. Sliwinska-Kowalska
- Department of Audiology and Phoniatrics, Nofer Institute of Occupational Medicine, Lodz, Poland
- Klinika Audiologii i Foniatrii, Instytut Medycyny Pracy im. prof. J. Nofera, ul. Sw. Teresy 8, 91-348 Lodz, Poland
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10
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Kim SJ, Lee JH, Kim BS, So HS, Park R, Myung NY, Um JY, Hong SH. (-)-Epigallocatechin-3-gallate protects against NO-induced ototoxicity through the regulation of caspase- 1, caspase-3, and NF-κB activation. PLoS One 2012; 7:e43967. [PMID: 23028481 PMCID: PMC3461011 DOI: 10.1371/journal.pone.0043967] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 07/30/2012] [Indexed: 12/16/2022] Open
Abstract
Excessive nitric oxide (NO) production is toxic to the cochlea and induces hearing loss. However, the mechanism through which NO induces ototoxicity has not been completely understood. The aim of this study was to gain further insight into the mechanism mediating NO-induced toxicity in auditory HEI-OC1 cells and in ex vivo analysis. We also elucidated whether and how epigallocatechin-3-gallate (EGCG), the main component of green tea polyphenols, regulates NO-induced auditory cell damage. To investigate NO-mediated ototoxicity, S-nitroso-N-acetylpenicillamine (SNAP) was used as an NO donor. SNAP was cytotoxic, generating reactive oxygen species, releasing cytochrome c, and activating caspase-3 in auditory cells. NO-induced ototoxicity also mediated the nuclear factor (NF)-κB/caspase-1 pathway. Furthermore, SNAP destroyed the orderly arrangement of the 3 outer rows of hair cells in the basal, middle, and apical turns of the organ of Corti from the cochlea of Sprague-Dawley rats at postnatal day 2. However, EGCG counteracted this ototoxicity by suppressing the activation of caspase-3/NF-κB and preventing the destruction of hair cell arrays in the organ of Corti. These findings may lead to the development of a model for pharmacological mechanism of EGCG and potential therapies against ototoxicity.
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Affiliation(s)
- Su-Jin Kim
- Department of Cosmeceutical Science, Daegu Hanny University, Kyungsan, Gyeoungbuk, Republic of Korea
| | - Jeong-Han Lee
- Center for Metabolic Function Regulation, Wonkwang University, Iksan, Republic of Korea
| | - Beom-Su Kim
- Wonkwang Bone Regeneration Research Institute, Wonkwang University, Iksan, Jeonbuk, Republic of Korea
| | - Hong-Seob So
- Center for Metabolic Function Regulation, Wonkwang University, Iksan, Republic of Korea
| | - Raekil Park
- Center for Metabolic Function Regulation, Wonkwang University, Iksan, Republic of Korea
| | - Noh-Yil Myung
- Center for Metabolic Function Regulation, Wonkwang University, Iksan, Republic of Korea
| | - Jae-Young Um
- College of Oriental Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Seung-Heon Hong
- Center for Metabolic Function Regulation, Wonkwang University, Iksan, Republic of Korea
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Heinrich UR, Helling K. Nitric oxide--a versatile key player in cochlear function and hearing disorders. Nitric Oxide 2012; 27:106-16. [PMID: 22659013 DOI: 10.1016/j.niox.2012.05.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 05/10/2012] [Accepted: 05/24/2012] [Indexed: 12/13/2022]
Abstract
Nitric oxide (NO) is a signaling molecule which can generally be formed by three nitric oxide synthases (NOS). Two of them, the endothelial nitric oxide synthase (eNOS) and the neural nitric oxide synthase (nNOS), are calcium/calmodulin-dependent and constitutively expressed in many cell types. Both isoforms are found in the vertebrate cochlea. The inducible nitric oxide synthase (iNOS) is independent of calcium and normally not detectable in the un-stimulated cochlea. In the inner ear, as in other tissues, NO was identified as a multitask molecule involved in various processes such as neurotransmission and neuromodulation. In addition, increasing evidence demonstrates that the NO-dependent processes of cell protection or, alternatively, cell destruction seem to depend, among other things, on changes in the local cochlear NO-concentration. These alterations can occur at the cellular level or within a distinct cell population both leading to an NO-imbalance within the hearing organ. This dysfunction can result in hearing loss or even in deafness. In cases of cochlear malfunction, regulatory systems such as the gap junction system, the blood vessels or the synaptic region might be affected temporarily or permanently by an altered NO-level. This review discusses potential cellular mechanisms how NO might contribute to different forms of hearing disorders. Approaches of NO-reduction are evaluated and the transfer of results obtained from experimental animal models to human medication is discussed.
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Affiliation(s)
- Ulf-Rüdiger Heinrich
- Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Center of The Johannes Gutenberg-University Mainz, Germany.
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12
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Alvarado JC, Fuentes-Santamaría V, Jareño-Flores T, Blanco JL, Juiz JM. Normal variations in the morphology of auditory brainstem response (ABR) waveforms: a study in Wistar rats. Neurosci Res 2012; 73:302-11. [PMID: 22595234 DOI: 10.1016/j.neures.2012.05.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 05/01/2012] [Accepted: 05/02/2012] [Indexed: 10/28/2022]
Abstract
Auditory brainstem evoked responses (ABR) have been used for decades to assess auditory function. Surprisingly, despite the fact that rats are one of the most widely used experimental models in hearing, there have been no studies that have characterized in detail the normal morphological variations that occur in ABR waves. Therefore, the goal of this study was to characterize the patterns of ABR waves in rats to establish baseline criteria that could be used to identify abnormalities. Rats were stimulated with pure tone sounds at different frequencies and ABR waves were classified based on morphology. The most definitive finding was that, unlike what is observed in human ABRs, wave II of the rat ABR was the most prominent. Additionally, wave III was the smallest and, in many cases, was not apparent at low frequencies. Wave III was frequently involved in the formation of complexes, often appearing as a small wave or adjoining primarily wave IV. Complexes were common at low and medium frequencies and rare at high frequencies. These results indicate that knowledge of the different wave patterns in normal rats is fundamental to understanding how the wave morphology changes in pathological conditions that could lead to hearing impairment.
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Affiliation(s)
- Juan Carlos Alvarado
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), 02006 Albacete, Spain.
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13
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Abstract
Normal blood supply to the cochlea is critically important for establishing the endocochlear potential and sustaining production of endolymph. Abnormal cochlear microcirculation has long been considered an etiologic factor in noise-induced hearing loss, age-related hearing loss (presbycusis), sudden hearing loss or vestibular function, and Meniere's disease. Knowledge of the mechanisms underlying the pathophysiology of cochlear microcirculation is of fundamental clinical importance. A better understanding of cochlear blood flow (CoBF) will enable more effective management of hearing disorders resulting from aberrant blood flow. This review focuses on recent discoveries and findings related to the physiopathology of the cochlear microvasculature.
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Affiliation(s)
- Xiaorui Shi
- Oregon Hearing Research Center (NRC04), Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
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14
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Reduced formation of oxidative stress biomarkers and migration of mononuclear phagocytes in the cochleae of chinchilla after antioxidant treatment in acute acoustic trauma. Int J Otolaryngol 2011; 2011:612690. [PMID: 21961007 PMCID: PMC3179894 DOI: 10.1155/2011/612690] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 07/19/2011] [Indexed: 02/01/2023] Open
Abstract
Objective. Inhibition of inflammation and free radical formation in the cochlea may be involved in antioxidant treatment in acute acoustic trauma. Procedure. Chinchilla were exposed to 105 dB sound pressure level octave band noise for 6 hours. One group of chinchilla was treated with antioxidants after noise exposure. Auditory brainstem responses, outer hair cell counts, and immunohistochemical analyses of biomarkers in the cochlea were conducted. Results. The antioxidant treatment significantly reduced hearing threshold shifts, outer hair cell loss, numbers of CD45+ cells, as well as 4-hydroxy-2-nonenal and nitrotyrosine formation in the cochlea. Conclusion. Antioxidant treatment may provide protection to sensory cells by inhibiting formation of reactive oxygen and nitrogen products and migration of mononuclear phagocytes in the cochlea. The present study provides further evidence of effectiveness of antioxidant treatment in reducing permanent hearing loss.
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Wu HP, Guo YL, Cheng TJ, Hsu CJ. Chronological changes in compromised olivocochlear activity and the effect of insulin in diabetic Wistar rats. Hear Res 2010; 270:173-8. [DOI: 10.1016/j.heares.2010.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2010] [Revised: 07/08/2010] [Accepted: 07/24/2010] [Indexed: 01/12/2023]
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Wu HP, Hsu CJ, Cheng TJ, Guo YL. N-acetylcysteine attenuates noise-induced permanent hearing loss in diabetic rats. Hear Res 2010; 267:71-7. [DOI: 10.1016/j.heares.2010.03.082] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Revised: 03/21/2010] [Accepted: 03/23/2010] [Indexed: 01/12/2023]
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In vivo protective effect of ferulic acid against noise-induced hearing loss in the guinea-pig. Neuroscience 2010; 169:1575-88. [PMID: 20600667 DOI: 10.1016/j.neuroscience.2010.06.022] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 06/09/2010] [Accepted: 06/10/2010] [Indexed: 02/07/2023]
Abstract
Ferulic acid (FA) is a phenolic compound whose neuroprotective activity was extensively studied in vitro. In this study, we provided functional in vivo evidence that FA limits noise-induced hearing loss. Guinea-pigs exposed to acoustic trauma for 1 h exhibited a significant impairment in auditory function; this injury was evident as early as 1 day from noise exposure and persisted over 21 days. Ferulic acid (150 mg/kg i.p. for 4 days) counteracted noise-induced hearing loss at days 1, 3, 7 and 21 from noise exposure. The improvement of auditory function by FA was paralleled by a significant reduction in oxidative stress, apoptosis and increase in hair cell viability in the organ of Corti. Interestingly in the guinea-pig cochleae, the neuroprotective effect of FA was functionally related not only to its scavenging ability in the peri-traumatic period but also to the up-regulation of the cytoprotective enzyme heme oxygenase-1 (HO-1); in fact, FA-induced improvement of auditory function was counteracted by the HO inhibitor zinc-protoporphyrin-IX and paralleled the time-course of HO-1 induction over 3-7 days. These results confirm the antioxidant properties of FA as free-radical scavenger and suggest a role of HO-1 as an additional mediator against noise-induced ototoxicity.
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Canis M, Arpornchayanon W, Messmer C, Suckfuell M, Olzowy B, Strieth S. An animal model for the analysis of cochlear blood flow [corrected] disturbance and hearing threshold in vivo. Eur Arch Otorhinolaryngol 2009; 267:197-203. [PMID: 19597836 DOI: 10.1007/s00405-009-1036-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 06/26/2009] [Indexed: 11/28/2022]
Abstract
Impairment of cochlear blood flow (CBF) is considered to be important in inner ear pathology. However, direct measurement of CBF is difficult and has not been investigated in combination with hearing function. Six guinea pigs were used to show feasibility of an animal model for the analysis of cochlear microcirculation by intravital microscopy in combination with investigation of the hearing threshold by brainstem response audiometry (ABR). By the application of sodium nitroprusside (SNP), CBF was increased over 30 min. Reproducibility of measurements was shown by retest measurements. Mean baseline velocity of CBF was 109 +/- 19 mum/s. Vessel diameters had a mean value of 9.4 +/- 2.7 mum. Mean hearing threshold was 19 +/- 6 dB. In response to SNP, CBF velocity increased significantly to 161 +/- 26 mum/s. Mean arterial pressure decreased significantly to 36 +/- 11 mmHg. After the end of the application, CBF velocity recovered to a minimum of 123 +/- 17 microm/s. Within the retest, CBF velocity significantly increased to a maximum of 160 +/- 31 microm/s. Second recovery of CBF velocity was 125 +/- 14 mum/s. Within the second retest, CBF increased significantly to 157 +/- 25 microm/s. ABR thresholds did not change significantly. The increase in blood flow velocity occurred in spite of substantial hypotension as induced by a vasodilator. This may explain the fact that ABR threshold remained unchanged reflecting a maintained blood supply in this part of the brain. This technique can be used to evaluate effects of treatments aimed at cochlear microcirculation in inner ear pathologies.
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Affiliation(s)
- Martin Canis
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Munich (LMU), Campus Grosshadern, Munich, Germany.
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Wu HP, Cheng TJ, Tan CT, Guo YL, Hsu CJ. Diabetes impairs recovery from noise-induced temporary hearing loss. Laryngoscope 2009; 119:1190-4. [PMID: 19358251 DOI: 10.1002/lary.20221] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVES/HYPOTHESIS The purpose of this study is to investigate whether diabetes impairs the recovery from noised-induced temporary hearing loss. METHODS Twenty-eight male Wistar rats were divided into three groups: control, diabetes with insulin control (DI), and diabetes without insulin control (DM). Diabetes was induced by intraperitoneal injection of streptozotocin. All animals were exposed to white noise at 110 dB SPL for 8 hours. Auditory brainstem response (ABR) thresholds and distortion product otoacoustic emission (DPOAE) amplitudes were measured for all animals 1 day prior to noise exposure to obtain a baseline for hearing function, and then 1 hour, 1 day, 2 days, 4 days, 7 days, and 14 days after noise exposure. RESULTS One hour post exposure, ABR thresholds shifted markedly, and DPOAE was reduced similarly in all groups. Both ABR thresholds and DPOAE returned to the baseline in the control group at day 1, but they were not back to the baseline in the DM group even by day 14. Compared with the control group, the ABR threshold shifts and DPOAE returned to baseline more slowly in the DI group. CONCLUSIONS The present study suggests that diabetic patients need proper blood sugar control and probably need more effective preventive measures to preserve their hearing from the effects of noise. Laryngoscope, 2009.
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Affiliation(s)
- Hung-Pin Wu
- Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, Taipei, Taiwan.
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Chronologic Changes of Nitric Oxide Concentration in the Cochlear Lateral Wall and Its Role in Noise-Induced Permanent Threshold Shift. Laryngoscope 2008; 118:832-6. [DOI: 10.1097/mlg.0b013e3181651c24] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Protection from noise-induced temporary threshold shift by D-methionine is associated with preservation of ATPase activities. Ear Hear 2008; 29:65-75. [PMID: 18091106 DOI: 10.1097/aud.0b013e31815d635b] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The present study was designed to test whether noise-induced temporary threshold shift (TTS) could be attenuated by D-methionine and its possible relation to the biochemical changes of cochlear lateral walls such as ATPase activities and oxidative stress in guinea pigs. DESIGN Thirty-two normal-hearing male guinea pigs were randomly divided into saline-treated and D-methionine-treated (300 mg/kg) experimental groups. One hour after treatment, they were exposed to a continuous broadband white noise at 105 +/- 2 dB sound pressure level for 10 min, causing TTS. Each group was then divided into four subgroups based on the number of survival days after noise exposure (0, 1, 2, and 7 days). Each subgroup had four animals and eight ears included. By means of click-evoked auditory brain stem responses (ABR), auditory thresholds of guinea pigs were measured before noise exposure, immediately after noise exposure, and before killing. After animals were killed, cochlear lateral walls were immediately harvested and assayed for enzyme-specific activities of Na+, K+-ATPase and Ca2+-ATPase, lipid peroxidation, and nitric oxide. RESULTS A 15.31 +/- 3.80 dB threshold shift was found immediately after noise exposure in saline-pretreated guinea pigs. In contrast, ABR threshold shift was significantly attenuated to 4.06 +/- 2.35 dB in D-methionine-treated animals. Furthermore, D-methionine enhanced the restoration of ABR threshold to baseline level by 1 day. In addition, noise significantly decreased Na+, K+-ATPase, and Ca2+-ATPase activities and increased lipid peroxidation and nitric oxide levels of the cochlear lateral walls. D-methionine significantly protected against all of these changes. CONCLUSIONS Noise not only induced TTS but also inhibited ATPase activities as well as increased oxidative stress in guinea-pig cochlear lateral walls; all of these changes could be attenuated by d-methionine through its antioxidative property. These results suggest the potential usefulness of d-methionine in protecting from noise-induced ototoxicity.
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Diao M, Gao W, Sun J. Nitric oxide synthase inhibitor reduces noise-induced cochlear damage in guinea pigs. Acta Otolaryngol 2007; 127:1162-7. [PMID: 17851886 DOI: 10.1080/00016480701242436] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
CONCLUSION The results obtained in this study indicate that NG-nitro-L-arginine methyl ester (L-NAME) protects cochlear damage from acoustic trauma through reducing the production of nitric oxide (NO). OBJECTIVES This study aimed to explore whether NO synthase inhibitor L-NAME could reduce cochlear damage in acoustic trauma. MATERIALS AND METHODS Seventy guinea pigs (300-350g) were divided randomly into four groups (n=20 in groups I, III, and IV; n=10 in group II). Two days consecutively and 30min before noise exposure (4kHz octave band, 115dB SPL 5h), subjects received an injection of 5ml saline/kg (groups I and III) or 10mg/kg L-NAME (groups II and IV). Sham-exposed guinea pigs were listed as groups I and II. Protection was assessed physiologically by the change in auditory brainstem response (ABR) threshold and histologically by survival of outer hair cells (OHCs). NO level of cochlear tissue was assayed 3days after noise exposure. RESULTS Group III showed significantly greater OHC loss, threshold shifts and NO level compared with group I and group IV. Compared with group III, noise-induced elevation in NO level in the cochlea was significantly attenuated by L-NAME (p<0.001).
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Affiliation(s)
- Mingfang Diao
- Center of Otolaryngology of PLA, Navy General Hospital, Beijing, 100037, PR China
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Le Prell CG, Yamashita D, Minami SB, Yamasoba T, Miller JM. Mechanisms of noise-induced hearing loss indicate multiple methods of prevention. Hear Res 2007; 226:22-43. [PMID: 17141991 PMCID: PMC1995566 DOI: 10.1016/j.heares.2006.10.006] [Citation(s) in RCA: 230] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2006] [Revised: 10/05/2006] [Accepted: 10/24/2006] [Indexed: 12/20/2022]
Abstract
Recent research has shown the essential role of reduced blood flow and free radical formation in the cochlea in noise-induced hearing loss (NIHL). The amount, distribution, and time course of free radical formation have been defined, including a clinically significant late formation 7-10 days following noise exposure, and one mechanism underlying noise-induced reduction in cochlear blood flow has finally been identified. These new insights have led to the formulation of new hypotheses regarding the molecular mechanisms of NIHL; and, from these, we have identified interventions that prevent NIHL, even with treatment onset delayed up to 3 days post-noise. It is essential to now assess the additive effects of agents intervening at different points in the cell death pathway to optimize treatment efficacy. Finding safe and effective interventions that attenuate NIHL will provide a compelling scientific rationale to justify human trials to eliminate this single major cause of acquired hearing loss.
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Affiliation(s)
- Colleen G Le Prell
- Kresge Hearing Research Institute, University of Michigan, 1301 East Ann Street, Ann Arbor, MI 48109-0506, USA.
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