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Xu K, Xu B, Gu J, Wang X, Yu D, Chen Y. Intrinsic mechanism and pharmacologic treatments of noise-induced hearing loss. Theranostics 2023; 13:3524-3549. [PMID: 37441605 PMCID: PMC10334830 DOI: 10.7150/thno.83383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 06/12/2023] [Indexed: 07/15/2023] Open
Abstract
Noise accounts for one-third of hearing loss worldwide. Regretfully, noise-induced hearing loss (NIHL) is deemed to be irreversible due to the elusive pathogenic mechanisms that have not been fully elucidated. The complex interaction between genetic and environmental factors, which influences numerous downstream molecular and cellular events, contributes to the NIHL. In clinical settings, there are no effective therapeutic drugs other than steroids, which are the only treatment option for patients with NIHL. Therefore, the need for treatment of NIHL that is currently unmet, along with recent progress in our understanding of the underlying regulatory mechanisms, has led to a lot of new literatures focusing on this therapeutic field. The emergence of novel technologies that modify local drug delivery to the inner ear has led to the development of promising therapeutic approaches, which are currently under clinical investigation. In this comprehensive review, we focus on outlining and analyzing the basics and potential therapeutics of NIHL, as well as the application of biomaterials and nanomedicines in inner ear drug delivery. The objective of this review is to provide an incentive for NIHL's fundamental research and future clinical translation.
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Affiliation(s)
- Ke Xu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Ear Institute, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Baoying Xu
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, China
| | - Jiayi Gu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Ear Institute, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Xueling Wang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Ear Institute, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Dehong Yu
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, China
| | - Yu Chen
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, China
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Kim J, Hemachandran S, Cheng AG, Ricci AJ. Identifying targets to prevent aminoglycoside ototoxicity. Mol Cell Neurosci 2022; 120:103722. [PMID: 35341941 PMCID: PMC9177639 DOI: 10.1016/j.mcn.2022.103722] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/14/2022] [Accepted: 03/19/2022] [Indexed: 12/21/2022] Open
Abstract
Aminoglycosides are potent antibiotics that are commonly prescribed worldwide. Their use carries significant risks of ototoxicity by directly causing inner ear hair cell degeneration. Despite their ototoxic side effects, there are currently no approved antidotes. Here we review recent advances in our understanding of aminoglycoside ototoxicity, mechanisms of drug transport, and promising sites for intervention to prevent ototoxicity.
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Affiliation(s)
- Jinkyung Kim
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sriram Hemachandran
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alan G Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Anthony J Ricci
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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3
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Nanocarriers for drug delivery to the inner ear: Physicochemical key parameters, biodistribution, safety and efficacy. Int J Pharm 2020; 592:120038. [PMID: 33159985 DOI: 10.1016/j.ijpharm.2020.120038] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 12/26/2022]
Abstract
Despite the high incidence of inner ear disorders, there are still no dedicated medications on the market. Drugs are currently administered by the intratympanic route, the safest way to maximize drug concentration in the inner ear. Nevertheless, therapeutic doses are ensured for only a few minutes/hours using drug solutions or suspensions. The passage through the middle ear barrier strongly depends on drug physicochemical characteristics. For the past 15 years, drug encapsulation into nanocarriers has been developed to overcome this drawback. Nanocarriers are well known to sustain drug release and protect it from degradation. In this review, in vivo studies are detailed concerning nanocarrier biodistribution, their pathway mechanisms in the inner ear and the resulting drug pharmacokinetics. Key parameters influencing nanocarrier biodistribution are identified and discussed: nanocarrier size, concentration, surface composition and shape. Recent advanced strategies that combine nanocarriers with hydrogels, specific tissue targeting or modification of the round window permeability (cell-penetrating peptide, magnetic delivery) are explored. Most of the nanocarriers appear to be safe for the inner ear and provide a significant efficacy over classic formulations in animal models. However, many challenges remain to be overcome for future clinical applications.
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Manohar S, Russo FY, Seigel GM, Salvi R. Dynamic Changes in Synaptic Plasticity Genes in Ipsilateral and Contralateral Inferior Colliculus Following Unilateral Noise-induced Hearing Loss. Neuroscience 2020; 436:136-153. [PMID: 32278721 DOI: 10.1016/j.neuroscience.2020.04.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/07/2020] [Accepted: 04/03/2020] [Indexed: 12/27/2022]
Abstract
Unilateral noise-induced hearing loss reduces the input to the central auditory pathway disrupting the excitatory and inhibitory inputs to the inferior colliculus (IC), an important binaural processing center. Little is known about the compensatory synaptic changes that occur in the IC as a consequence of unilateral noise-induced hearing loss. To address this issue, Sprague-Dawley rats underwent unilateral noise exposure resulting in severe unilateral hearing loss. IC tissues from the contralateral and ipsilateral IC were evaluated for acute (2-d) and chronic (28-d) changes in the expression of 84 synaptic plasticity genes on a PCR array. Arc and Egr1 genes were further visualized by in situ hybridization to validate the PCR results. None of the genes were upregulated, but many were downregulated post-exposure. At 2-d post-exposure, more than 75% of the genes were significantly downregulated in the contralateral IC, while only two were downregulated in the ipsilateral IC. Many of the downregulated genes were related to long-term depression, long-term potentiation, cell adhesion, immediate early genes, neural receptors and postsynaptic density. At 28-d post-exposure, the gene expression pattern was reversed with more than 85% of genes in the ipsilateral IC now downregulated. Most genes previously downregulated in the contralateral IC 2-d post-exposure had recovered; less than 15% remained downregulated. These time-dependent, asymmetric changes in synaptic plasticity gene expression could shed new light on the perceptual deficits associated with unilateral hearing loss and the dynamic structural and functional changes that occur in the IC days and months following unilateral noise-induced hearing loss.
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Affiliation(s)
| | | | - Gail M Seigel
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY 14214, USA
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY 14214, USA.
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Dkhar B, Bhatia A, Saikia PP, Pyngrope H. Improved postauricular surgical approach to the round window of rats. J Neurosci Methods 2020; 330:108481. [PMID: 31669291 DOI: 10.1016/j.jneumeth.2019.108481] [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: 12/21/2018] [Revised: 10/21/2019] [Accepted: 10/22/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVES Research using rat as an in-vivo model has played an important role in otological research. The rat ear anatomy has been described; however, detailed surgical procedures to access the temporal bone are limited. The authors present a technique to approach the inner ear of rat that was standardized by cadaveric dissections and later replicated in living animals. METHODS Adult Wistar albino rats were dissected via the post-auricular approach. The emphasis was on early identification of the facial nerve that formed a reliable landmark for the tympanic bulla, which in turn houses the round window and stapedial artery. The point of identification of facial nerve was postero-inferior to the external auditory meatus. The procedure was then repeated in living animals. RESULTS Seventeen cadaveric rats were dissected. Initially, the investigators attempted to identify the facial nerve at its crossing over the external auditory meatus. However, that method was found to be unsatisfactory. The facial nerve was then attempted to be identified in its course postero-inferior to the external auditory meatus. The technique improved drastically, and the facial nerve was identified promptly and reliably. The procedure was then repeated in seven living rats under general anaesthesia. The major issues encountered were bleeding from the stapedial artery, hematoma of the pinna in one rat. CONCLUSION This study suggests that the post-auricular approach is a feasible and less time consuming route for round window drug delivery experiments in Wistar albino rats. Recognition of anatomical landmarks, particularly the facial nerve is the key to surgery.
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Affiliation(s)
- Barilin Dkhar
- Department of ENT, North Eastern Indira Gandhi Regional Institute of Health & Medical Sciences (NEIGRIHMS), Shillong, 793018, Meghalaya, India
| | - Abhijeet Bhatia
- Department of ENT, North Eastern Indira Gandhi Regional Institute of Health & Medical Sciences (NEIGRIHMS), Shillong, 793018, Meghalaya, India.
| | - Pranjal Pratim Saikia
- Department of Pharmacology, North Eastern Indira Gandhi Regional Institute of Health & Medical Sciences (NEIGRIHMS), Shillong, 793018, Meghalaya, India
| | - Haphidasara Pyngrope
- Department of ENT, North Eastern Indira Gandhi Regional Institute of Health & Medical Sciences (NEIGRIHMS), Shillong, 793018, Meghalaya, India
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Guo J, Chai R, Li H, Sun S. Protection of Hair Cells from Ototoxic Drug-Induced Hearing Loss. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1130:17-36. [PMID: 30915699 DOI: 10.1007/978-981-13-6123-4_2] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Hair cells are specialized sensory epithelia cells that receive mechanical sound waves and convert them into neural signals for hearing, and these cells can be killed or damaged by ototoxic drugs, including many aminoglycoside antibiotics, platinum-based anticancer agents, and loop diuretics, leading to drug-induced hearing loss. Studies of therapeutic approaches to drug-induced hearing loss have been hampered by the limited understanding of the biological mechanisms that protect and regenerate hair cells. This review briefly discusses some of the most common ototoxic drugs and describes recent research concerning the mechanisms of ototoxic drug-induced hearing loss. It also highlights current developments in potential therapies and explores current clinical treatments for patients with hearing impairments.
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Affiliation(s)
- Jin Guo
- Key Laboratory of Hearing Medicine of NHFPC, ENT Institute and Otorhinolaryngology Department, Shanghai Engineering Research Centre of Cochlear Implant, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Renjie Chai
- Key Laboratory of Hearing Medicine of NHFPC, ENT Institute and Otorhinolaryngology Department, Shanghai Engineering Research Centre of Cochlear Implant, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,MOE Key Laboratory for Developmental Genes and Human Disease, Institute of Life Sciences, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
| | - Huawei Li
- Key Laboratory of Hearing Medicine of NHFPC, ENT Institute and Otorhinolaryngology Department, Shanghai Engineering Research Centre of Cochlear Implant, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Shan Sun
- Key Laboratory of Hearing Medicine of NHFPC, ENT Institute and Otorhinolaryngology Department, Shanghai Engineering Research Centre of Cochlear Implant, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.
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7
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Horvath L, Bächinger D, Honegger T, Bodmer D, Naldi AM. Functional and morphological analysis of different aminoglycoside treatment regimens inducing hearing loss in mice. Exp Ther Med 2019; 18:1123-1130. [PMID: 31316607 PMCID: PMC6601143 DOI: 10.3892/etm.2019.7687] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 05/23/2019] [Indexed: 01/05/2023] Open
Abstract
Aminoglycoside ototoxicity is common in clinical practice but reliable protective agents currently do not exist. Aminoglycoside regimens causing ototoxicity in different laboratory animals are under investigation. The assessment method used most commonly to determine auditory effects is the auditory brainstem response (ABR). Distortion product otoacoustic emissions (DPOAE) have been used less frequently. A precise recommendation on the specific method to assess peripheral auditory function before and after aminoglycoside toxicity in mice does not exist. In order to evaluate various mouse models for ototoxic injury caused by various aminoglycoside regimens, there is a need for performing preliminary tests in small cohorts before large experiments. The aim of our study was to investigate different aminoglycoside regimens that cause substantial ototoxic damage in vivo. Aminoglycosides are safe and produce a detectable hearing threshold shift in a small cohort of mice that can be used as a model for preliminary tests. Different ototoxic regimens were assessed by ABR and DPOAE measurements pre- and post-treatment. Further, the sensory cell loss was quantified by counting hair cells in the cochlea. It was revealed that an ototoxic regimen with kanamycin twice daily for 15 consecutive days is safe, well tolerated and produces an early significant hearing threshold shift detected by DPOAE in a small cohort of mice. The study compared ABR and DPOAE in mentioned regimens for the first time and illustrated that DPOAE is well suited for detecting hearing threshold shifts in high frequencies before ABR threshold shifts occur in accordance with predominating outer hair cell damage mainly in the basal turn of the cochlea.
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Affiliation(s)
- Lukas Horvath
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Zurich, University Hospital Zurich, 8091 Zurich, Switzerland.,Department of Biomedicine and The Clinic for Otorhinolaryngology, University Hospital Basel, 4031 Basel, Switzerland
| | - David Bächinger
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Zurich, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Tim Honegger
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Zurich, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Daniel Bodmer
- Department of Biomedicine and The Clinic for Otorhinolaryngology, University Hospital Basel, 4031 Basel, Switzerland
| | - Arianne Monge Naldi
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Zurich, University Hospital Zurich, 8091 Zurich, Switzerland
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Manohar S, Ramchander PV, Salvi R, Seigel GM. Synaptic Reorganization Response in the Cochlear Nucleus Following Intense Noise Exposure. Neuroscience 2018; 399:184-198. [PMID: 30593923 DOI: 10.1016/j.neuroscience.2018.12.023] [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: 07/27/2018] [Revised: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 12/13/2022]
Abstract
The cochlear nucleus, located in the brainstem, receives its afferent auditory input exclusively from the auditory nerve fibers of the ipsilateral cochlea. Noise-induced neurodegenerative changes occurring in the auditory nerve stimulate a cascade of neuroplastic changes in the cochlear nucleus resulting in major changes in synaptic structure and function. To identify some of the key molecular mechanisms mediating this synaptic reorganization, we unilaterally exposed rats to a high-intensity noise that caused significant hearing loss and then measured the resulting changes in a synaptic plasticity gene array targeting neurogenesis and synaptic reorganization. We compared the gene expression patterns in the dorsal cochlear nucleus (DCN) and ventral cochlear nucleus (VCN) on the noise-exposed side versus the unexposed side using a PCR gene array at 2 d (early) and 28 d (late) post-exposure. We discovered a number of differentially expressed genes, particularly those related to synaptogenesis and regeneration. Significant gene expression changes occurred more frequently in the VCN than the DCN and more changes were seen at 28 d versus 2 d post-exposure. We confirmed the PCR findings by in situ hybridization for Brain-derived neurotrophic factor (Bdnf), Homer-1, as well as the glutamate NMDA receptor Grin1, all involved in neurogenesis and plasticity. These results suggest that Bdnf, Homer-1 and Grin1 play important roles in synaptic remodeling and homeostasis in the cochlear nucleus following severe noise-induced afferent degeneration.
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Affiliation(s)
- S Manohar
- University at Buffalo, Center for Hearing and Deafness, 3435 Main Street, Cary 137, Buffalo, NY 14214, United States
| | - P V Ramchander
- University at Buffalo, Center for Hearing and Deafness, 3435 Main Street, Cary 137, Buffalo, NY 14214, United States
| | - R Salvi
- University at Buffalo, Center for Hearing and Deafness, 3435 Main Street, Cary 137, Buffalo, NY 14214, United States.
| | - G M Seigel
- University at Buffalo, Center for Hearing and Deafness, 3435 Main Street, Cary 137, Buffalo, NY 14214, United States
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Tian K, Song Y, Zhou K, Yue B, Qiu Y, Sun F, Wang R, Zha D, Qiu J. Upregulation of HSP60 expression in the postnatal rat cochlea and rats with drug-induced hearing loss. Cell Stress Chaperones 2018; 23:1311-1317. [PMID: 30196524 PMCID: PMC6237686 DOI: 10.1007/s12192-018-0938-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 07/09/2018] [Accepted: 09/02/2018] [Indexed: 10/28/2022] Open
Abstract
Heat shock protein 60 (HSP60) is a highly conserved chaperone molecule that plays important roles in mediating some physiological and pathological functions. However, researchers have not yet determined whether HSP60 is expressed in the mammalian cochlea. This study constitutes the first investigation of the expression of HSP60 in the postnatal rat cochlea. We also examined the expression of HSP60 in rats with drug-induced hearing loss. Auditory thresholds were assessed by monitoring the auditory brainstem response (ABR) prior to and after drug injection. Expression levels of the HSP60 gene (Hsp60) and HSP60 protein in the rat cochlea were detected by quantitative real-time polymerase chain reaction and Western blotting, respectively. The distribution of HSP60 in the rat cochlea was further examined by immunofluorescence staining. We have demonstrated that HSP60 was expressed in the postnatal rat cochlea in an age-dependent and cell-specific manner. In addition, after drug exposure, the average hearing threshold of rats in the experimental group was significantly higher than that in the control group, with increased HSP60 expression level in response to kanamycin and furosemide treatments. HSP60 expression was observed in the supporting cells (SCs) within the organ of Corti in both the uninjured and the injured cochlea, but it was undetectable in the mechanosensory hair cells (HCs) and spiral ganglion neurons. Therefore, our research suggests that HSP60 may play an important role in auditory function.
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Affiliation(s)
- Keyong Tian
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 127 Changle Western Road, Xi'an, 710032, Shannxi Province, China
| | - Yongli Song
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 127 Changle Western Road, Xi'an, 710032, Shannxi Province, China
| | - Ke Zhou
- Department of Clinical Laboratory, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Bo Yue
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 127 Changle Western Road, Xi'an, 710032, Shannxi Province, China
| | - Yang Qiu
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 127 Changle Western Road, Xi'an, 710032, Shannxi Province, China
| | - Fei Sun
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 127 Changle Western Road, Xi'an, 710032, Shannxi Province, China
| | - Renfeng Wang
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 127 Changle Western Road, Xi'an, 710032, Shannxi Province, China
| | - Dingjun Zha
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 127 Changle Western Road, Xi'an, 710032, Shannxi Province, China
| | - Jianhua Qiu
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, 127 Changle Western Road, Xi'an, 710032, Shannxi Province, China.
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Circulating Serum miRNA-205 as a Diagnostic Biomarker for Ototoxicity in Mice Treated with Aminoglycoside Antibiotics. Int J Mol Sci 2018; 19:ijms19092836. [PMID: 30235835 PMCID: PMC6163699 DOI: 10.3390/ijms19092836] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 09/15/2018] [Accepted: 09/17/2018] [Indexed: 12/22/2022] Open
Abstract
Background: To confirm levels and detection timing of circulating microRNAs (miRNAs) in the serum of a mouse model for diagnosis of ototoxicity, circulating miR-205 in the serum was evaluated to reflect damages in the cochlear microstructure and compared to a kidney injury model. Method: A microarray for miRNAs in the serum was performed to assess the ototoxic effects of kanamycin-furosemide. Changes in the levels for the selected miRNAs (miR-205, miR-183, and miR-103) were compared in the serum and microstructures of the cochlea (stria vascularis, organ of Corti, and modiolus) between the ototoxicity and normal mouse groups. An acute kidney injury (AKI) mouse model was used to assess changes in miR-205 levels in the kidney by ototoxic drugs. Results: In the mouse model for ototoxicity, the serum levels of circulating miR-205 peaked on day 3 and were sustained from days 7–14. Furthermore, miR-205 expression was highly expressed in the organ of Corti at day 5, continued to be expressed in the modiolus at high levels until day 14, and was finally also in the stria vascularis. The serum miR-205 in the AKI mice did not change significantly compared to the normal group. Conclusions Circulating miR-205 from the cochlea, after ototoxic damage, migrates through the blood vessels to organs, which is then finally found in blood. In conditions of hearing impairment with ototoxic medications, detection of circulating miR-205 in the blood can be used to determine the extent of hearing loss. In the future, inner ear damage can be identified by simply performing a blood test before the hearing impairment due to ototoxic drugs.
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Ototoxic effects and mechanisms of loop diuretics. J Otol 2016; 11:145-156. [PMID: 29937824 PMCID: PMC6002634 DOI: 10.1016/j.joto.2016.10.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 12/22/2022] Open
Abstract
Over the past two decades considerable progress has been made in understanding the ototoxic effects and mechanisms underlying loop diuretics. As typical representative of loop diuretics ethacrynic acid or furosemide only induces temporary hearing loss, but rarely permanent deafness unless applied in severe acute or chronic renal failure or with other ototoxic drugs. Loop diuretic induce unique pathological changes in the cochlea such as formation of edematous spaces in the epithelium of the stria vascularis, which leads to rapid decrease of the endolymphatic potential and eventual loss of the cochlear microphonic potential, summating potential, and compound action potential. Loop diuretics interfere with strial adenylate cyclase and Na+/K+-ATPase and inhibit the Na-K-2Cl cotransporter in the stria vascularis, however recent reports indicate that one of the earliest effects in vivo is to abolish blood flow in the vessels supplying the lateral wall. Since ethacrynic acid does not damage the stria vascularis in vitro, the changes in Na+/K+-ATPase and Na-K-2Cl seen in vivo may be secondary effects results from strial ischemia and anoxia. Recent observations showing that renin is present in pericytes surrounding stria arterioles suggest that diuretics may induce local vasoconstriction by renin secretion and angiotensin formation. The tight junctions in the blood-cochlea barrier prevent toxic molecules and pathogens from entering cochlea, but when diuretics induce a transient ischemia, the barrier is temporarily disrupted allowing the entry of toxic chemicals or pathogens.
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Abstract
As most gene sequences and functional structures of internal organs in rats have been well studied, rat models are widely used in experimental medical studies. A large number of descriptions and atlas of the rat temporal bone have been published, but some detailed anatomy of its surface and inside structures remains to be studied. By focusing on some unique characteristics of the rat temporal bone, the current paper aims to provide more accurate and detailed information on rat temporal bone anatomy in an attempt to complete missing or unclear areas in the existed knowledge. We also hope this paper can lay a solid foundation for experimental rat temporal bone surgeries, and promote information exchange among colleagues, as well as providing useful guidance for novice researchers in the field of hearing research involving rats.
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Affiliation(s)
- Peng Li
- Department of Otolaryngology, Head and Neck Surgery, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.,Center for Hearing and Deafness, State University of New York at Buffalo, Buffalo, NY 14214, USA
| | - Kelei Gao
- Center for Hearing and Deafness, State University of New York at Buffalo, Buffalo, NY 14214, USA.,Department of Otolaryngology, Head and Neck Surgery, Xiangya Hospital, Central South University, Hunan 410013, China
| | - Dalian Ding
- Department of Otolaryngology, Head and Neck Surgery, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.,Center for Hearing and Deafness, State University of New York at Buffalo, Buffalo, NY 14214, USA.,Department of Otolaryngology, Head and Neck Surgery, Xiangya Hospital, Central South University, Hunan 410013, China
| | - Richard Salvi
- Center for Hearing and Deafness, State University of New York at Buffalo, Buffalo, NY 14214, USA.,Department of Otolaryngology, Head and Neck Surgery, Xiangya Hospital, Central South University, Hunan 410013, China
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13
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Li P, Ding D, Gao K, Salvi R. Standardized surgical approaches to ear surgery in rats. J Otol 2015; 10:72-77. [PMID: 29937785 PMCID: PMC6002556 DOI: 10.1016/j.joto.2015.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 03/15/2015] [Accepted: 03/30/2015] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVE To describe several approaches of ear surgeries for experimental studies in rats. METHODS Anesthetized rats were prepared for demonstration of various ear surgery approaches designed to optimize experimental outcomes in studies with specific goals and exposure requirements. The surgical approaches included the posterior tympanum, superior tympanum, inferior tympanum and occipital approaches. RESULTS The middle ear cavity and inner ear were successfully exposed from different angles via the mentioned surgical approaches. For example, electrode placement for recording of cochlear bioelectric responses was easily achieved through the posterior tympanum or inferior tympanum approach. Alternatively, drug delivery or gene transfection via round window membrane was most easily accomplished using the posterior tympanum approach. Cochlear perfusion of protective or ototoxic drugs was best performed using the inferior tympanum approach. Ossicular chain interruption to induce a prolonged conductive hearing loss was readily achieved using a superior tympanum approach. Lastly, surgical destruction of the endolymphatic sac to induce experimental endolymphatic hydrops was readily performed via an occipital surgical approach. CONCLUSION These standardized surgical approaches can be applied in scientific studies of the ear with different purposes covering electrophysiology, conductive hearing loss, intra-cochlear drug perfusion and experimental studies relevant to Meniere's disease.
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Affiliation(s)
- Peng Li
- Department of Otolaryngology Head and Neck Surgery, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510630, China
- Center for Hearing and Deafness, University of New York at Buffalo, Buffalo, NY 14214, USA
| | - Dalian Ding
- Center for Hearing and Deafness, University of New York at Buffalo, Buffalo, NY 14214, USA
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Hunan 410018, China
| | - Kelei Gao
- Center for Hearing and Deafness, University of New York at Buffalo, Buffalo, NY 14214, USA
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Hunan 410018, China
| | - Richard Salvi
- Center for Hearing and Deafness, University of New York at Buffalo, Buffalo, NY 14214, USA
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Hunan 410018, China
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Pattern of hair cell loss and delayed peripheral neuron degeneration in inner ear by a high-dose intratympanic gentamicin. J Otol 2014. [DOI: 10.1016/j.joto.2014.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Abstract
HYPOTHESIS How to induce most efficiently severe sensorineural hearing loss in mice using a single coadministration of an aminoglycoside antibiotic and a loop diuretic? BACKGROUND The coadministration of aminoglycosides and a loop diuretic has been widely used to induce hair cell and spiral ganglion cell loss in guinea pigs. However, the development of new treatment strategies against sensorineural hearing loss, such as tissue engineering techniques, requires the use of mouse models. Previous attempts to induce hearing loss in mice have rendered inconsistent results because of resistance to aminoglycoside-induced ototoxicity. Especially inner hair cells seem to be resistant to aminoglycoside-induced ototoxicity. METHODS In the present study, we aim to optimize hearing loss in mice, using a single high-dose kanamycin (700 and 1,000 mg/kg) injection followed by a furosemide (100 mg/kg) administration. Although previous studies used intraperitoneal furosemide injections 30 minutes after kanamycin administration, we used intravenous furosemide injections administered within 5 minutes after kanamycin treatment. RESULTS Auditory brain stem responses illustrated severe threshold shifts, and histologic analysis showed marked outer hair cell destruction as well as spiral ganglion cell loss. The present protocol results in more severe inner hair cell loss when compared with the results of previous researches. CONCLUSION We conclude that severe sensorineural hearing loss can be induced in mice. Moreover, we found that this mouse model can be augmented via the use of rapid intravenous furosemide administrations to maximize inner hair cell loss.
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