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Choi JE, Chang SY, Lee MY, Park I, Jung JY. Photobiomodulation with near-infrared laser for tinnitus management: preliminary animal experiments and randomized clinical trials. Lasers Med Sci 2024; 39:224. [PMID: 39198335 DOI: 10.1007/s10103-024-04175-z] [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: 04/17/2024] [Accepted: 08/20/2024] [Indexed: 09/01/2024]
Abstract
This study investigates the effectiveness of photobiomodulation therapy (PBMT) in treating chronic high-frequency tinnitus with the TINI device, a near-infrared (830 nm) laser. The study includes preliminary animal experiments with 28 mice and a randomized controlled trial with 56 participants to examine the functional and molecular changes in the auditory system that PBMT may cause. The animal model used sodium salicylate to induce tinnitus, followed by PBMT, which showed promising reductions in the behavioral evidence of tinnitus and a reversal of tinnitus-associated upregulation of vesicular glutamate transporters 2 expression in the ipsilateral dorsal cochlear nucleus (p < 0.05). In the clinical trial, participants with chronic high-frequency tinnitus received trans-tympanic application of the TINI device. The results did not show a significant difference in tinnitus score at the final time point when compared to the sham group. However, questionnaires revealed significant improvements in tinnitus symptoms and psychological outcomes following treatment with the TINI device compared to before treatment (p < 0.05). These findings suggest that while PBMT has potential benefits, its clinical effectiveness may be unclear due to its complex nature and interaction with other conditions. Further research is required to optimize treatment parameters and gain a complete understanding of the therapeutic potential of PBMT in managing tinnitus.
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Affiliation(s)
- Ji Eun Choi
- Department of Otorhinolaryngology-Head and Neck Surgery, Dankook University Hospital, 119, Dandae-ro, Dongnam-gu, Cheonan-si, Chungcheongnam-do, 31116, Republic of Korea
| | - So-Young Chang
- Department of Laser Institute-Korea, Dankook University College of Medicine, 119, Dandae-ro, Dongnam-gu, Cheonan-si, Chungcheongnam-do, 31116, Republic of Korea
| | - Min Young Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Dankook University Hospital, 119, Dandae-ro, Dongnam-gu, Cheonan-si, Chungcheongnam-do, 31116, Republic of Korea
- Department of Laser Institute-Korea, Dankook University College of Medicine, 119, Dandae-ro, Dongnam-gu, Cheonan-si, Chungcheongnam-do, 31116, Republic of Korea
| | - Ilyong Park
- Department of Laser Institute-Korea, Dankook University College of Medicine, 119, Dandae-ro, Dongnam-gu, Cheonan-si, Chungcheongnam-do, 31116, Republic of Korea
- Department of Biomedical Engineering, Dankook University College of Medicine, 119, Dandae-ro, Dongnam-gu, Cheonan-si, Chungcheongnam-do, 31116, Republic of Korea
| | - Jae Yun Jung
- Department of Otorhinolaryngology-Head and Neck Surgery, Dankook University Hospital, 119, Dandae-ro, Dongnam-gu, Cheonan-si, Chungcheongnam-do, 31116, Republic of Korea.
- Department of Laser Institute-Korea, Dankook University College of Medicine, 119, Dandae-ro, Dongnam-gu, Cheonan-si, Chungcheongnam-do, 31116, Republic of Korea.
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Montazeri K, Farhadi M, Majdabadi A, Akbarnejad Z, Fekrazad R, Shahbazi A, Mahmoudian S. Photobiomodulation therapy in improvement of harmful neural plasticity in sodium salicylate-induced tinnitus. PLoS One 2024; 19:e0296607. [PMID: 38626075 PMCID: PMC11020422 DOI: 10.1371/journal.pone.0296607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 03/12/2024] [Indexed: 04/18/2024] Open
Abstract
Tinnitus is a common annoying symptom without effective and accepted treatment. In this controlled experimental study, photobiomodulation therapy (PBMT), which uses light to modulate and repair target tissue, was used to treat sodium salicylate (SS)-induced tinnitus in a rat animal model. Here, PBMT was performed simultaneously on the peripheral and central regions involved in tinnitus. The results were evaluated using objective tests including gap pre-pulse inhibition of acoustic startle (GPIAS), auditory brainstem response (ABR) and immunohistochemistry (IHC). Harmful neural plasticity induced by tinnitus was detected by doublecortin (DCX) protein expression, a known marker of neural plasticity. PBMT parameters were 808 nm wavelength, 165 mW/cm2 power density, and 99 J/cm2 energy density. In the tinnitus group, the mean gap in noise (GIN) value of GPIAS test was significantly decreased indicated the occurrence of an additional perceived sound like tinnitus and also the mean ABR threshold and brainstem transmission time (BTT) were significantly increased. In addition, a significant increase in DCX expression in the dorsal cochlear nucleus (DCN), dentate gyrus (DG) and the parafloccular lobe (PFL) of cerebellum was observed in the tinnitus group. In PBMT group, a significant increase in the GIN value, a significant decrease in the ABR threshold and BTT, and also significant reduction of DCX expression in the DG were observed. Based on our findings, PBMT has the potential to be used in the management of SS-induced tinnitus.
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Affiliation(s)
- Katayoon Montazeri
- The Five Senses Health Institute, ENT and Head and Neck Research Center, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Mohammad Farhadi
- The Five Senses Health Institute, ENT and Head and Neck Research Center, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Abbas Majdabadi
- Dentistry Research Institute, Laser Research Center of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Zainab Akbarnejad
- The Five Senses Health Institute, ENT and Head and Neck Research Center, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Reza Fekrazad
- Radiation Sciences Research Center, Laser Research Center in Medical Sciences, AJA University of Medical Sciences, Tehran, Iran
| | - Ali Shahbazi
- Faculty of Advanced Technologies in Medicine, Department of Neuroscience, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Saeid Mahmoudian
- The Five Senses Health Institute, ENT and Head and Neck Research Center, School of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
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Nikookam Y, Zia N, Lotfallah A, Muzaffar J, Davis-Manders J, Kullar P, Smith ME, Bale G, Boyle P, Irving R, Jiang D, Bance M. The effect of photobiomodulation on tinnitus: a systematic review. J Laryngol Otol 2023:1-22. [PMID: 37994052 DOI: 10.1017/s0022215123002165] [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: 11/24/2023]
Abstract
OBJECTIVE To establish outcomes following photobiomodulation therapy for tinnitus in humans and animal studies. METHODS A systematic review and narrative synthesis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The databases searched were: Medline, Embase, Cochrane Central Register of Controlled Trials ('Central'), ClinicalTrials.gov and Web of Science including the Web of Science Core collection. There were no limits on language or year of publication. RESULTS The searches identified 194 abstracts and 61 full texts. Twenty-eight studies met the inclusion criteria, reporting outcomes in 1483 humans (26 studies) and 34 animals (2 studies). Photobiomodulation therapy parameters included 10 different wavelengths, and duration ranged from 9 seconds to 30 minutes per session. Follow up ranged from 7 days to 6 months. CONCLUSION Tinnitus outcomes following photobiomodulation therapy are generally positive and superior to no photobiomodulation therapy; however, evidence of long-term therapeutic benefit is deficient. Photobiomodulation therapy enables concentrated, focused delivery of light therapy to the inner ear through a non-invasive manner, with minimal side effects.
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Affiliation(s)
- Yasmin Nikookam
- Department of Ear, Nose and Throat Surgery, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK
| | - Nawal Zia
- Department of Ear, Nose and Throat Surgery, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK
| | - Andrew Lotfallah
- Department of Ear, Nose and Throat Surgery, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK
| | - Jameel Muzaffar
- Department of Ear, Nose and Throat Surgery, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK
- Department of Clinical Neurosciences, Addenbrooke's Health Campus, University of Cambridge, Cambridge, UK
| | - Jennifer Davis-Manders
- Department of Ear, Nose and Throat Surgery, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK
| | - Peter Kullar
- Department of Clinical Neurosciences, Addenbrooke's Health Campus, University of Cambridge, Cambridge, UK
| | - Matthew E Smith
- Department of Clinical Neurosciences, Addenbrooke's Health Campus, University of Cambridge, Cambridge, UK
| | - Gemma Bale
- Department of Physics, University of Cambridge, Cambridge, UK
- Department of Electrical Engineering, University of Cambridge, Cambridge, UK
| | | | - Richard Irving
- Department of Ear, Nose and Throat Surgery, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK
| | - Dan Jiang
- Hearing Implant Centre, St Thomas' Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK
- Centre for Craniofacial and Regenerative Biology, Guy's Hospital Campus, King's College London, London, UK
| | - Manohar Bance
- Department of Clinical Neurosciences, Addenbrooke's Health Campus, University of Cambridge, Cambridge, UK
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Bousema EJ, Koops EA, van Dijk P, Dijkstra PU. Effects of Physical Interventions on Subjective Tinnitus, a Systematic Review and Meta-Analysis. Brain Sci 2023; 13:brainsci13020226. [PMID: 36831769 PMCID: PMC9954385 DOI: 10.3390/brainsci13020226] [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: 12/02/2022] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 01/31/2023] Open
Abstract
Increasingly, patients suffering from subjective tinnitus seek help from physical therapists. Numerous randomised controlled trials (RCTs) have investigated the effect of physical interventions commonly used in physical therapy practice on subjective tinnitus. This systematic review and meta-analysis aimed to analyse the effects of physical interventions on tinnitus loudness, tinnitus annoyance, and scores on the Tinnitus Handicap Index (THI). Four databases were searched from inception up to March 2022. A total of 39 RCTs were included in the systematic review, and 23 studies were appropriate for meta-analyses. Risk of bias assessments were also performed. Interventions analysed in at least five studies were summarised, including transcutaneous electrical nerve stimulation (TENS), laser therapy, and acupuncture. Random-effects meta-analysis models were used, and effect sizes were expressed as Hedge's standardised mean differences (SMD) with 95%CI's. The quality of three-quarters of the studies was limited due to insufficient allocation concealment, lack of adequate blinding, and small sample sizes. Large, pooled effects sizes were found for acupuncture (SMD: 1.34; 95%CI: 0.79, 1.88) and TENS (SMD: 1.17; 95%CI: 0.48, 1.87) on THI as well as for acupuncture on tinnitus loudness (VAS Loudness (SMD: 0.84; 95%CI: 0.33, 1.36) and tinnitus annoyance (SMD: 1.18; 95%CI: 0.00, 2.35). There is some evidence that physical interventions (TENS and acupuncture, but not laser therapy) may be effective for tinnitus. However, the lack of high-quality studies and the risk of bias in many studies prohibits stronger conclusions.
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Affiliation(s)
- Eric J. Bousema
- Department of Otorhinolaryngology, Head & Neck Surgery, University of Groningen, University Medical Centre Groningen, 9712 CP Groningen, The Netherlands
- Fysiotherapie Sittard Oost, 6137 RX Sittard, The Netherlands
- Correspondence: ; Tel.: +31-630-878505
| | - Elouise A. Koops
- Department of Otorhinolaryngology, Head & Neck Surgery, University of Groningen, University Medical Centre Groningen, 9712 CP Groningen, The Netherlands
- Graduate School of Medical Sciences, Research School of Behavioural and Cognitive Neurosciences, University of Groningen, 9712 CP Groningen, The Netherlands
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Pim van Dijk
- Department of Otorhinolaryngology, Head & Neck Surgery, University of Groningen, University Medical Centre Groningen, 9712 CP Groningen, The Netherlands
- Graduate School of Medical Sciences, Research School of Behavioural and Cognitive Neurosciences, University of Groningen, 9712 CP Groningen, The Netherlands
| | - Pieter U. Dijkstra
- Department of Oral and Maxillofacial Surgery, University of Groningen, University Medical Centre Groningen, 9712 CP Groningen, The Netherlands
- Department of Rehabilitation Medicine, University of Groningen, University Medical Centre Groningen, 9712 CP Groningen, The Netherlands
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The effects of photobiomodulation therapy in individuals with tinnitus and without hearing loss. Lasers Med Sci 2022; 37:3485-3494. [PMID: 35947315 DOI: 10.1007/s10103-022-03614-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 03/22/2021] [Indexed: 10/15/2022]
Abstract
To verify the effect of photobiomodulation therapy (PBMT) in individuals with chronic tinnitus without hearing loss, 20 patients who met the inclusion criteria were randomly divided into group 1: active low-level laser (LLL) and group 2: equipment without laser (placebo). Upon anamnesis, data collection, and audiological exams, the Tinnitus Handicap Inventory (THI) and the Visual-Analog Scale (EVA) were applied to measure the level of discomfort with tinnitus and the level of discomfort before and after laser treatment. The protocol used included 12 active LLL sessions for group 1 and not active for group 2, varying red and infrared wavelengths. There was a reduction in the disadvantage of individuals with tinnitus after the intervention and between the initial and final sessions, regardless of the intervention, although group 1 showed a greater reduction than group 2, regardless of point in time of assessment and number of session. There was no statistical difference as to group and point in time for the high-frequency audiometry and acuphenometry outcomes. Individuals with chronic tinnitus reduced the complaint, regardless of point in time and group of intervention; however, the group that received PBMT improved the level of satisfaction, regardless of point in time of assessment and number of session.
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Kim MJ, Park SY, Park JM, Yu HJ, Park I, Park SN. Evidence of Tinnitus Development Due to Stress: An Experimental Study in Rats. Laryngoscope 2021; 131:2332-2340. [PMID: 34156095 DOI: 10.1002/lary.29691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 01/12/2023]
Abstract
OBJECTIVES/HYPOTHESIS Tinnitus can develop due to, or be aggravated by, stress in a rat model. To investigate stress as a possible causal factor in the development of tinnitus, we designed an animal study that included tinnitus behavior and excitatory/inhibitory neurotransmitter expression after noise exposure as well as restraint stress. STUDY DESIGN An experimental animal study. METHODS Wistar rats were grouped according to single or double exposure to noise and restraint stress. The noise exposure (NE) group was subjected to 110 dB sound pressure level (SPL) of 16 kHz narrow-band noise (NBN) for 1 hour, and the restraint stress (RS) group was restrained for 1 hour with or without noise exposure. Gap prepulse inhibition of the acoustic startle (GPIAS) reflex was measured at an NBN of 16 kHz to investigate tinnitus development. Various immunohistopathologic and molecular biologic studies were undertaken to evaluate possible mechanisms of tinnitus development after noise and/or restraint stress. RESULTS The RS-only group showed a reduced GPIAS response, which is a reliable sign of tinnitus development. In the double-stimulus groups, more tinnitus-development signs of reduced GPIAS responses were observed. The expression of γ-aminobutyric acid A receptor α1 (GABAAR α1) in the hippocampus decreased in the NE│RS group. Increased N-methyl-d-aspartate receptor1 intensities in the NE│RS group and decreased GABAAR α1 intensities in the RS and NE│RS groups were observed in the CA3 region of the hippocampus. CONCLUSIONS Tinnitus appeared to develop after stress alone in this animal study. An imbalance in excitatory and inhibitory neurotransmitters in the hippocampus may be related to the development of tinnitus after acute NE and/or stress. LEVEL OF EVIDENCE NA Laryngoscope, 2021.
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Affiliation(s)
- Min Jung Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Department of Biomedicine and Health Sciences, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - So Young Park
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jung Mee Park
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Department of Otorhinolaryngology-Head and Neck Surgery, Gangneung Asan Hospital, College of Medicine University of Ulsan, Gangneung, Republic of Korea
| | - Hyo Jeong Yu
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Department of Biomedicine and Health Sciences, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Ilyong Park
- Department of Biomedical Engineering, College of Medicine, Dankook University, Cheonan, Republic of Korea
| | - Shi Nae Park
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Department of Biomedicine and Health Sciences, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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Kim YC, Kim H, Kim YS, Jung SK, Park IY, Choung YH, Jang JH. Objective Verification of Acute Tinnitus and Validation of Efficacy of Systemic Steroids in Rats. J Korean Med Sci 2020; 35:e81. [PMID: 32242342 PMCID: PMC7131900 DOI: 10.3346/jkms.2020.35.e81] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 02/02/2020] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND This study was performed to identify acute tinnitus and evaluate the efficacy of steroids for noise-induced acute tinnitus by measuring the gap-prepulse inhibition of the acoustic startle (GPIAS) value in an animal model. METHODS Nineteen rats (the noise group [n = 7] and the noise + dexamethasone [DEX] group [n = 12]) were exposed to narrow-band noise centered at 16 kHz from a sound generator for 4 hours. The noise + DEX group received intraperitoneal steroid administration daily for 5 days (1.5 mg/kg/day) after completing noise exposure. Auditory brainstem response and GPIAS value were measured just prior to, and 1 day after noise exposure and on days 1 and 10 days after completing steroid administration. The changes in cochlear structure were evaluated by histological analysis. RESULTS The threshold shift was checked 1 and 10 days after intraperitoneal steroid injection, and no differences in threshold shift were observed between the two groups in each frequency except for 32 kHz 1 day after steroid injection. The mean GPIAS value in the noise + DEX group (36.4% ± 14.1%) was significantly higher than that in the noise group (16.4% ± 18.8%) 10 days after intraperitoneal steroid administration (P = 0.017). There were no pathological changes associated with noise trauma in the two groups as determined on hematoxylin and eosin and immunohistochemical staining. CONCLUSION An acute tinnitus model with minimal structural changes by noise exposure was set up, and used to verify tinnitus objectively by measuring the GPIAS value. Steroid therapy for control of tinnitus was validated in this animal model.
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Affiliation(s)
- Yeong Cheol Kim
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, Korea
- Department of Biomedical Sciences, BK21 Plus Research Center for Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Korea
| | - Heejin Kim
- Department of Otorhinolaryngology Head and Neck Surgery, Dongtan Sacred Heart Hospital, Hallym University College of Medicine, Hwaseong, Korea
| | - Young Seon Kim
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, Korea
| | - Seo Kyung Jung
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, Korea
- Department of Biomedical Sciences, BK21 Plus Research Center for Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Korea
| | - Il Yong Park
- Department of Biomedical Engineering, College of Medicine, Dankook University, Cheonan, Korea
| | - Yun Hoon Choung
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, Korea
- Department of Biomedical Sciences, BK21 Plus Research Center for Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Korea
| | - Jeong Hun Jang
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, Korea.
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A Mouse Model of Tinnitus Using Gap Prepulse Inhibition of the Acoustic Startle in an Accelerated Hearing Loss Strain. Otol Neurotol 2020; 41:e516-e525. [DOI: 10.1097/mao.0000000000002573] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Holt AG, Kühl A, Braun RD, Altschuler R. The rat as a model for studying noise injury and otoprotection. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:3681. [PMID: 31795688 DOI: 10.1121/1.5131344] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A major challenge for those studying noise-induced injury pre-clinically is the selection of an animal model. Noise injury models are particularly relevant in an age when people are constantly bombarded by loud noise due to occupation and/or recreation. The rat has been widely used for noise-related morphological, physiological, biochemical, and molecular assessment. Noise exposure resulting in a temporary (TTS) or permanent threshold shift (PTS) yields trauma in peripheral and central auditory related pathways. While the precise nature of noise-related injuries continues to be delineated, both PTS and TTS (with or without hidden hearing loss) result in homeostatic changes implicated in conditions such as tinnitus and hyperacusis. Compared to mice, rats generally tolerate exposure to loud sounds reasonably well, often without exhibiting other physical non-inner ear related symptoms such as death, loss of consciousness, or seizures [Skradski, Clark, Jiang, White, Fu, and Ptacek (2001). Neuron 31, 537-544; Faingold (2002). Hear. Res. 168, 223-237; Firstova, Abaimov, Surina, Poletaeva, Fedotova, and Kovalev (2012). Bull Exp. Biol. Med. 154, 196-198; De Sarro, Russo, Citraro, and Meldrum (2017). Epilepsy Behav. 71, 165-173]. This ability of the rat to thrive following noise exposure permits study of long-term effects. Like the mouse, the rat also offers a well-characterized genome allowing genetic manipulations (i.e., knock-out, viral-based gene expression modulation, and optogenetics). Rat models of noise-related injury also provide valuable information for understanding mechanistic changes to identify therapeutic targets for treatment. This article provides a framework for selection of the rat as a model for noise injury studies.
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Affiliation(s)
- Avril Genene Holt
- Department of Ophthalmology, Visual, and Anatomical Sciences (OVAS), School of Medicine, Wayne State University, 550 East Canfield Avenue, 454 Lande Building, Detroit, Michigan 48201, USA
| | - André Kühl
- Department of Ophthalmology, Visual, and Anatomical Sciences (OVAS), School of Medicine, Wayne State University, 550 East Canfield Avenue, 454 Lande Building, Detroit, Michigan 48201, USA
| | - Rod D Braun
- Department of Ophthalmology, Visual, and Anatomical Sciences (OVAS), School of Medicine, Wayne State University, 550 East Canfield Avenue, 454 Lande Building, Detroit, Michigan 48201, USA
| | - Richard Altschuler
- Department of Otolaryngology; Cell and Developmental Biology, Kresge Hearing Research Institute, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, Michigan 48109, USA
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Sorg K, Stahn P, Pillong L, Hinsberger MP, Heimann L, Foth HJ, Schick B, Wenzel GI. First biocompatibility margins for optical stimulation at the eardrum via 532-nm laser pulses in a mouse model. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-10. [PMID: 31436071 PMCID: PMC6983485 DOI: 10.1117/1.jbo.24.8.085003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
Hearing impairment affects ∼460 million people worldwide. Conservative therapies, such as hearing aids, bone conduction systems, and middle ear implants, do not always sufficiently compensate for this deficit. The optical stimulation is currently under investigation as an alternative stimulation strategy for the activation of the hearing system. To assess the biocompatibility margins of this emerging technology, we established a method applicable in whole-mount preparations of murine tympanic membranes (TM). We irradiated the TM of anesthetized mice with 532-nm laser pulses at an average power of 50, 89, 99, and 125 mW at two different locations of the TM and monitored the hearing function with auditory brainstem responses. Laser-power-dependent negative side effects to the TM were observed at power levels exceeding 89 mW. Although we did not find any significant negative effects of optical stimulation on the hearing function in these mice, based on the histology results further studies are necessary for optimization of the used parameters.
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Affiliation(s)
- Katharina Sorg
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
| | - Patricia Stahn
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
| | - Lukas Pillong
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
| | - Marius P. Hinsberger
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
| | - Larissa Heimann
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
| | - Hans-Jochen Foth
- University of Kaiserslautern, Department of Physics, Kaiserslautern, Germany
| | - Bernhard Schick
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
| | - Gentiana I. Wenzel
- Saarland University, Department of Otolaryngology, Faculty of Medicine, Homburg, Germany
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Effects of transient auditory deprivation during critical periods on the development of auditory temporal processing. Int J Pediatr Otorhinolaryngol 2018; 104:66-71. [PMID: 29287884 DOI: 10.1016/j.ijporl.2017.10.045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 10/29/2017] [Accepted: 10/30/2017] [Indexed: 01/27/2023]
Abstract
OBJECTIVES The central auditory pathway matures through sensory experiences and it is known that sensory experiences during periods called critical periods exert an important influence on brain development. The present study aimed to investigate whether temporary auditory deprivation during critical periods (CPs) could have a detrimental effect on the development of auditory temporal processing. MATERIALS AND METHODS Twelve neonatal rats were randomly assigned to control and study groups; Study group experienced temporary (18-20 days) auditory deprivation during CPs (Early deprivation study group). Outcome measures included changes in auditory brainstem response (ABR), gap prepulse inhibition of the acoustic startle reflex (GPIAS), and gap detection threshold (GDT). To further delineate the specific role of CPs in the outcome measures above, the same paradigm was applied in adult rats (Late deprivation group) and the findings were compared with those of the neonatal rats. RESULTS Soon after the restoration of hearing, early deprivation study animals showed a significantly lower GPIAS at intermediate gap durations and a larger GDT than early deprivation controls, but these differences became insignificant after subsequent auditory inputs. Additionally, the ABR results showed significantly delayed latencies of waves IV, V, and interpeak latencies of wave I-III and wave I-V in study group. Late deprivation group didn't exhibit any deterioration in temporal processing following sensory deprivation. CONCLUSION Taken together, the present results suggest that transient auditory deprivation during CPs might cause reversible disruptions in the development of temporal processing.
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The effects of postnatal phthalate exposure on the development of auditory temporal processing in rats. Int J Pediatr Otorhinolaryngol 2017; 97:61-65. [PMID: 28483253 DOI: 10.1016/j.ijporl.2017.03.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/26/2017] [Accepted: 03/29/2017] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The central auditory pathway is known to continue its development during the postnatal critical periods and is shaped by experience and sensory inputs. Phthalate, a known neurotoxic material, has been reported to be associated with attention deficits in children, impacting many infant neurobehaviors. The objective of this study was to investigate the potential effects of neonatal phthalate exposure on the development of auditory temporal processing. METHODS Neonatal Sprague-Dawley rats were randomly assigned into two groups: The phthalate group (n = 6), and the control group (n = 6). Phthalate was given once per day from postnatal day 8 (P8) to P28. Upon completion, at P28, the Auditory Brainstem Response (ABR) and Gap Prepulse Inhibition of Acoustic Startle response (GPIAS) at each gap duration (2, 5, 10, 20, 50 and 80 ms) were measured, and gap detection threshold (GDT) was calculated. These outcomes were compared between the two groups. RESULTS Hearing thresholds by ABR showed no significant differences at all frequencies between the two groups. Regarding GPIAS, no significant difference was observed, except at a gap duration of 20 ms (p = 0.037). The mean GDT of the phthalate group (44.0 ms) was higher than that of the control group (20.0 ms), but without statistical significance (p = 0.065). Moreover, the phthalate group tended to demonstrate more of a scattered distribution in the GDT group than the in the control group. CONCLUSION Neonatal phthalate exposure may disrupt the development of auditory temporal processing in rats.
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Demirkol N, Usumez A, Demirkol M, Sari F, Akcaboy C. Efficacy of Low-Level Laser Therapy in Subjective Tinnitus Patients with Temporomandibular Disorders. Photomed Laser Surg 2017; 35:427-431. [PMID: 28294697 DOI: 10.1089/pho.2016.4240] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
OBJECTIVE AND BACKGROUND Tinnitus is an apparent sound, perceived in the ear with no stimulus. It has been described as a sound originating from the brain. It affects 17% of the general population. Etiological factors for tinnitus include temporomandibular joint disorders (TMJ, TMD) and Costen's syndrome. The aim of treatment is to eliminate the tinnitus or at least decrease its apparent volume. MATERIALS AND METHODS In total, 46 patients referred to our department with bilateral subjective tinnitus with TMDs were selected for this study. Low-level laser therapy (LLLT) with an neodymium-doped yttrium aluminum garnet (Nd:YAG) (1064 nm) laser, LLLT with a diode laser (810 nm), and placebo treatment were applied to the patients. There were 15 patients each in the Nd:YAG and placebo groups and 16 patients in the 810 nm diode laser group. LLLT was applied for 10 days, once per day. A visual analog scale (VAS) was used, with values between 0 and 10. VAS scores were recorded before treatment, on the last day of treatment, and 1 month after treatment. The VAS scores were the same on the last day of treatment and 1 month after treatment. The VAS scores before treatment and at 1 month after treatment were compared in a statistical analysis. RESULTS There were statistically significant differences in the Nd:YAG laser (p = 0.001) and 810 nm diode laser groups (p = 0.005), but no difference in the placebo group (p = 0.065). CONCLUSIONS Both the Nd:YAG and 810 nm diode lasers were effective for the treatment of subjective tinnitus related to TMDs.
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Affiliation(s)
- Nermin Demirkol
- 1 Department of Prosthodontics, Faculty of Dentistry, Gaziantep University , Gaziantep, Turkey
| | | | - Mehmet Demirkol
- 3 Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Gaziantep University , Gaziantep, Turkey
| | - Fatih Sari
- 1 Department of Prosthodontics, Faculty of Dentistry, Gaziantep University , Gaziantep, Turkey
| | - Cihan Akcaboy
- 4 Department of Prosthodontics, Faculty of Dentistry, Gazi University , Ankara, Turkey
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Jones A, May BJ. Improving the Reliability of Tinnitus Screening in Laboratory Animals. J Assoc Res Otolaryngol 2016; 18:183-195. [PMID: 27807642 DOI: 10.1007/s10162-016-0597-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 10/17/2016] [Indexed: 12/21/2022] Open
Abstract
Behavioral screening remains a contentious issue for animal studies of tinnitus. Most paradigms base a positive tinnitus test on an animal's natural tendency to respond to the "sound" of tinnitus as if it were an actual sound. As a result, animals with tinnitus are expected to display sound-conditioned behaviors when no sound is present or to miss gaps in background sounds because tinnitus "fills in the gap." Reliable confirmation of the behavioral indications of tinnitus can be problematic because the reinforcement contingencies of conventional discrimination tasks break down an animal's tendency to group tinnitus with sound. When responses in silence are rewarded, animals respond in silence regardless of their tinnitus status. When responses in silence are punished, animals stop responding. This study introduces stimulus classification as an alternative approach to tinnitus screening. Classification procedures train animals to respond to the common perceptual features that define a group of sounds (e.g., high pitch or narrow bandwidth). Our procedure trains animals to drink when they hear tinnitus and to suppress drinking when they hear other sounds. Animals with tinnitus are revealed by their tendency to drink in the presence of unreinforced probe sounds that share the perceptual features of the tinnitus classification. The advantages of this approach are illustrated by taking laboratory rats through a testing sequence that includes classification training, the experimental induction of tinnitus, and postinduction screening. Behavioral indications of tinnitus are interpreted and then verified by simulating a known tinnitus percept with objective sounds.
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Affiliation(s)
- Aikeen Jones
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Traylor Research Building, Room 521, 720 Rutland Avenue, Baltimore, MD, 21205, USA
| | - Bradford J May
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Traylor Research Building, Room 521, 720 Rutland Avenue, Baltimore, MD, 21205, USA.
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Lee JH, Chang SY, Moy WJ, Oh C, Kim SH, Rhee CK, Ahn JC, Chung PS, Jung JY, Lee MY. Simultaneous bilateral laser therapy accelerates recovery after noise-induced hearing loss in a rat model. PeerJ 2016; 4:e2252. [PMID: 27547558 PMCID: PMC4963219 DOI: 10.7717/peerj.2252] [Citation(s) in RCA: 251] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 06/23/2016] [Indexed: 11/22/2022] Open
Abstract
Noise-induced hearing loss is a common type of hearing loss. The effects of laser therapy have been investigated from various perspectives, including in wound healing, inflammation reduction, and nerve regeneration, as well as in hearing research. A promising feature of the laser is its capability to penetrate soft tissue; depending on the wavelength, laser energy can penetrate into the deepest part of the body without damaging non-target soft tissues. Based on this idea, we developed bilateral transtympanic laser therapy, which uses simultaneous laser irradiation in both ears, and evaluated the effects of bilateral laser therapy on cochlear damage caused by noise overexposure. Thus, the purpose of this research was to assess the benefits of simultaneous bilateral laser therapy compared with unilateral laser therapy and a control. Eighteen Sprague-Dawley rats were exposed to narrow-band noise at 115 dB SPL for 6 h. Multiple auditory brainstem responses were measured after each laser irradiation, and cochlear hair cells were counted after the 15th such irradiation. The penetration depth of the 808 nm laser was also measured after sacrifice. Approximately 5% of the laser energy reached the contralateral cochlea. Both bilateral and unilateral laser therapy decreased the hearing threshold after noise overstimulation in the rat model. The bilateral laser therapy group showed faster functional recovery at all tested frequencies compared with the unilateral laser therapy group. However, there was no difference in the endpoint ABR results or final hair cell survival, which was analyzed histologically.
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Affiliation(s)
- Jae-Hun Lee
- College of Medicine, Dankook University, Beckman Laser Institute Korea , Cheonan , South Korea
| | - So-Young Chang
- College of Medicine, Dankook University, Beckman Laser Institute Korea , Cheonan , South Korea
| | - Wesley J Moy
- Beckman Laser Institute and Medical Clinic, University of California , Irvine , CA , United States
| | - Connie Oh
- Beckman Laser Institute and Medical Clinic, University of California , Irvine , CA , United States
| | - Se-Hyung Kim
- Department of Otolaryngology-Head and Neck Surgery, Jeju National University School of Medicine , Jeju , South Korea
| | - Chung-Ku Rhee
- Department of Otolaryngology-Head & Neck Surgery, College of Medicine, Dankook University , Cheonan , South Korea
| | - Jin-Chul Ahn
- Department of Biomedical Science, College of Medicine, Dankook University , Cheonan , South Korea
| | - Phil-Sang Chung
- College of Medicine, Dankook University, Beckman Laser Institute Korea, Cheonan, South Korea; Department of Otolaryngology-Head & Neck Surgery, College of Medicine, Dankook University, Cheonan, South Korea
| | - Jae Yun Jung
- College of Medicine, Dankook University, Beckman Laser Institute Korea, Cheonan, South Korea; Department of Otolaryngology-Head & Neck Surgery, College of Medicine, Dankook University, Cheonan, South Korea
| | - Min Young Lee
- Department of Otolaryngology-Head & Neck Surgery, College of Medicine, Dankook University , Cheonan , South Korea
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Safety assessment of trans-tympanic photobiomodulation. Lasers Med Sci 2016; 31:323-33. [PMID: 26738500 DOI: 10.1007/s10103-015-1851-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 12/08/2015] [Indexed: 12/16/2022]
Abstract
We evaluated functional and morphological changes after trans-tympanic laser application using several different powers of photobiomodulation (PBM). The left (L) ears of 17 rats were irradiated for 30 min daily over 14 days using a power density of 909.1 (group A, 5040 J), 1136.4 (group B, 6300 J), and 1363.6 (group C, 7560 J) mW/cm(2). The right (N) ears served as controls. The safety of PBM was determined by endoscopic findings, auditory brainstem response (ABR) thresholds, and histological images of hair cells using confocal microscopy, and light microscopic images of the external auditory canal (EAC) and tympanic membrane (TM). Endoscopic findings revealed severe inflammation in the TM of C group; no other group showed damage in the TM. No significant difference in ABR threshold was found in the PBM-treated groups (excluding the group with TM damage). Confocal microscopy showed no histological difference between the AL and AN, or BL and BN groups. However, light microscopy showed more prominent edema, inflammation, and vascular congestion in the TM of BL ears. This study found a dose-response relationship between laser power parameters and TM changes. These results will be useful for defining future allowance criteria for trans-tympanic laser therapies.
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Galazyuk A, Hébert S. Gap-Prepulse Inhibition of the Acoustic Startle Reflex (GPIAS) for Tinnitus Assessment: Current Status and Future Directions. Front Neurol 2015; 6:88. [PMID: 25972836 PMCID: PMC4411996 DOI: 10.3389/fneur.2015.00088] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 04/09/2015] [Indexed: 02/06/2023] Open
Abstract
The progress in the field of tinnitus largely depends on the development of a reliable tinnitus animal model. Recently, a new method based on the acoustic startle reflex modification was introduced for tinnitus screening in laboratory animals. This method was enthusiastically adopted and now widely used by many scientists in the field due to its seeming simplicity and a number of advantages over the other methods of tinnitus assessment. Furthermore, this method opened an opportunity for tinnitus assessment in humans as well. Unfortunately, multiple modifications of data collection and interpretation implemented in different labs make comparisons across studies very difficult. In addition, recent animal and human studies have challenged the original “filling-in” interpretation of the paradigm. Here, we review the current literature to emphasize on the commonalities and differences in data collection and interpretation across laboratories that are using this method for tinnitus assessment. We also propose future research directions that could be taken in order to establish whether or not this method is warranted as an indicator of the presence of tinnitus.
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Affiliation(s)
- Alexander Galazyuk
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University , Rootstown, OH , USA
| | - Sylvie Hébert
- International Laboratory for Research on Brain, Music, and Sound (BRAMS), Faculty of Medicine, School of Speech Pathology and Audiology, Université de Montréal , Montréal, QC , Canada
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Thabit MN, Fouad N, Shahat B, Youssif M. Combined Central and Peripheral Stimulation for Treatment of Chronic Tinnitus. Neurorehabil Neural Repair 2014; 29:224-33. [DOI: 10.1177/1545968314542616] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background. Tinnitus is a common untreatable condition that originates from central maladaptive plasticity initiated by peripheral injury. Repetitive transcranial magnetic stimulation (rTMS), direct cochlear low-level laser therapy (LLLT), and acupuncture were tried for tinnitus treatment, but the results of these methods were clinically unsatisfactory. Objective. This study aimed to test the combined effect of the 3 methods targeting both peripheral and central auditory areas as a new therapeutic strategy for tinnitus. Methods. For this, 30 patients were randomized to 3 equal groups receiving 3 different interventions: inhibitory rTMS to the left auditory cortex, LLLT (which includes a combination of direct cochlear LLLT and laser acupuncture) to the affected ear(s), and finally, a combination of rTMS and LLLT. The Tinnitus Handicap Inventory (THI) and Visual Analogue Scale (VAS) were assessed before, immediately after, and at 2 weeks and 4 weeks after 10 consecutive every-other-day sessions for each intervention type. Results. We found that combined stimulation was effective in tinnitus treatment. This effect remained for 4 weeks after the end of the treatment. However, each of rTMS and LLLT alone had no significant effect. Repeated-measures ANOVA showed a significant effect of Time and Time × Intervention interaction for THI and VAS scores. The post hoc t test for different time points per intervention revealed a significant difference between baseline and all postintervention measurements of both THI and VAS for the combination intervention. Conclusion. Combined central rTMS and peripheral LLLT is more beneficial as a new method for management of tinnitus rather than these two used separately.
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Jung DJ, Han M, Jin SU, Lee SH, Park I, Cho HJ, Kwon TJ, Lee HJ, Cho JH, Lee KY, Chang Y. Functional mapping of the auditory tract in rodent tinnitus model using manganese-enhanced magnetic resonance imaging. Neuroimage 2014; 100:642-9. [PMID: 24983712 DOI: 10.1016/j.neuroimage.2014.06.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/20/2014] [Accepted: 06/23/2014] [Indexed: 10/25/2022] Open
Abstract
Animal models of salicylate-induced tinnitus have demonstrated that salicylate modulates neuronal activity in several brain structures leading to neuronal hyperactivity in auditory and non-auditory brain areas. In addition, these animal tinnitus models indicate that tinnitus can be a perceptual consequence of altered spontaneous neural activity along the auditory pathway. Peripheral and/or central effects of salicylate can account for neuronal activity changes in salicylate-induced tinnitus. Because of this ambiguity, an in vivo imaging study would be able to address the peripheral and/or central involvement of salicylate-induced tinnitus. Therefore, in the present study, we developed a novel manganese-enhanced magnetic resonance imaging (MEMRI) method to map the in vivo functional auditory tract in a salicylate-induced tinnitus animal model by administrating manganese through the round window. We found that acute salicylate-induced tinnitus resulted in higher manganese uptake in the cochlea and in the central auditory structures. Furthermore, serial MRI scans demonstrated that the manganese signal increased in an anterograde fashion from the cochlea to the cochlear nucleus. Therefore, our in vivo MEMRI data suggest that acute salicylate-induced tinnitus is associated with higher spontaneous neural activity both in peripheral and central auditory pathways.
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Affiliation(s)
- Da Jung Jung
- Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Mun Han
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Seong-Uk Jin
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Sang Heun Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Daegu Veterans Hospital, Daegu, Republic of Korea
| | - Ilyong Park
- Department of Biomedical Engineering, College of Medicine, Dankook University, Cheonan, Republic of Korea
| | - Hyun-Ju Cho
- Department of Biology, College of Natural Science, Kyungpook National University, Daegu, Republic of Korea
| | - Tae-Jun Kwon
- Department of Biology, College of Natural Science, Kyungpook National University, Daegu, Republic of Korea
| | - Hui Joong Lee
- Department of Radiology, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Jin Ho Cho
- Department of Electronic Engineering, College of IT Engineering, Kyungpook National University, Daegu, Republic of Korea
| | - Kyu-Yup Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea.
| | - Yongmin Chang
- Department of Medical and Biological Engineering, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea; Department of Radiology, School of Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea; Department of Molecular Medicine, BK21 Plus KNU Biomedical Convergence Program, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.
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Abstract
Tinnitus is one of the major audiological diseases, affecting a significant portion of the ageing society. Despite its huge personal and presumed economic impact there are only limited therapeutic options available. The reason for this deficiency lies in the very nature of the disease as it is deeply connected to elementary plasticity of auditory processing in the central nervous system. Understanding these mechanisms is essential for developing a therapy that reverses the plastic changes underlying the pathogenesis of tinnitus. This requires experiments that address individual neurons and small networks, something usually not feasible in human patients. However, in animals such invasive experiments on the level of single neurons with high spatial and temporal resolution are possible. Therefore, animal models are a very critical element in the combined efforts for engineering new therapies. This review provides an overview over the most important features of animal models of tinnitus: which laboratory species are suitable, how to induce tinnitus, and how to characterize the perceived tinnitus by behavioral means. In particular, these aspects of tinnitus animal models are discussed in the light of transferability to the human patients.
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