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Williams E, Minesinger K, Gallagher H, Stefanson JR, Bridges N, Jackson N, Stark V, Coto J, Rajguru S, Yankaskas K, Rogers R, Hoffer ME. Examining the utility of near infrared light as pre-exposure therapy to mitigate temporary noise-induced hearing loss in humans. Front Neurol 2024; 15:1366239. [PMID: 38711557 PMCID: PMC11072974 DOI: 10.3389/fneur.2024.1366239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/04/2024] [Indexed: 05/08/2024] Open
Abstract
Introduction This study sought to determine the effect of Occupational Safety and Health Administration (OSHA) compliant noise on auditory health and assess whether pre-noise near infrared (NIR) light therapy can mitigate the effects of noise exposure. Methods Over four visits, participants (n = 30, NCT#: 03834714) with normal hearing completed baseline hearing health assessments followed by exposure to open ear, continuous pink noise at 94 dBA for 15 min. Immediately thereafter, post-noise hearing tests at 3000, 4000, and 6000 Hz and distortion product otoacoustic emissions (DPOAEs) were conducted along with the Modified Rhyme Test (MRT), Masking Level Difference Test (MLD), and Fixed Level Frequency Tests (FLFT) [collectively referred to as the Central and Peripheral Auditory Test Battery (CPATB)] to acquire baseline noise sensitivity profiles. Participants were then randomized to either Active or Sham NIR light therapy for 30 min binaurally to conclude Visit 1. Visit 2 (≥24 and ≤ 48 h from Visit 1) began with an additional 30-min session of Active NIR light therapy or Sham followed by repeat CPATB testing and noise exposure. Post-noise testing was again conducted immediately after noise exposure to assess the effect of NIR light therapy. The remaining visits were conducted following ≥2 weeks of noise rest in a cross-over design (i.e., those who had received Active NIR light therapy in Visits 1 and 2 received Sham therapy in Visits 3 and 4). Results Recovery hearing tests and DPOAEs were completed at the end of each visit. Participants experienced temporary threshold shifts (TTS) immediately following noise exposure, with a mean shift of 6.79 dB HL (±6.25), 10.61 dB HL (±6.89), and 7.30 dB HL (±7.25) at 3000, 4000, and 6000 Hz, respectively, though all thresholds returned to baseline at 3000, 4000, and 6000 Hz within 75 min of noise exposure. Paradoxically, Active NIR light therapy threshold shifts were statistically higher than Sham therapy at 3000 Hz (p = 0.04), but no other differences were observed at the other frequencies tested. An age sub-analysis demonstrated that TTS among younger adults were generally larger in the Sham therapy group versus Active therapy, though this was not statistically different. There were no differences in CPATB test results across Active or Sham groups. Finally, we observed no changes in auditory function or central processing following noise exposure, suggestive of healthy and resilient inner ears. Conclusion In this study, locally administered NIR prior to noise exposure did not induce a significant protective effect in mitigating noise-induced TTS. Further exploration is needed to implement effective dosage and administration for this promising otoprotective therapy.
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Affiliation(s)
- Erin Williams
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, United States
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Kayla Minesinger
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Hilary Gallagher
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Dayton, OH, United States
| | - J. R. Stefanson
- U.S. Army Aeromedical Research Laboratory, Fort Rucker, AL, United States
| | - Nathaniel Bridges
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Dayton, OH, United States
| | - Natalie Jackson
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States
| | - Valerie Stark
- University of Miami Miller School of Medicine, Miami, FL, United States
| | - Jennifer Coto
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Suhrud Rajguru
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | | | - Rick Rogers
- BioInnovations Institute, Natick, MA, United States
| | - Michael E. Hoffer
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, United States
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Nikookam Y, Zia N, Lotfallah A, Muzaffar J, Davis-Manders J, Kullar P, Smith M, Bale G, Boyle P, Irving R, Jiang D, Bance M. The effect of photobiomodulation on hearing loss: A systematic review. Clin Otolaryngol 2024; 49:41-61. [PMID: 37885344 DOI: 10.1111/coa.14113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/16/2023] [Accepted: 10/07/2023] [Indexed: 10/28/2023]
Abstract
OBJECTIVES To assess outcomes associated with photobiomodulation therapy (PBMT) for hearing loss in human and animal studies. DESIGN Systematic review and narrative synthesis in accordance with PRISMA guidelines. SETTING Data bases searched: MEDLINE, EMBASE, CENTRAL, ClinicalTrials.gov and Web of Science. No limits were placed on language or year of publication. Review conducted in accordance with the PRISMA 2020 statement. PARTICIPANTS All human and animal subjects treated with PBMT for hearing loss. MAIN OUTCOME MEASURES Pre- and post-PBMT audio metric outcomes. RESULTS Searches identified 122 abstracts and 49 full text articles. Of these, 17 studies met the inclusion criteria, reporting outcomes in 327 animals (11 studies), 30 humans (1 study), and 40 animal specimens (5 studies). PBMT parameters included 6 different wavelengths: 908 nm (1 study), 810 nm (1 study), 532 & 635 nm (1 study), 830 nm (3 studies), 808 nm (11 studies). The duration ranged from 4 to 60 minutes in a session, and the follow-up ranged from 5-28 days. Outcomes improved significantly when wavelengths within the range of 800-830 nm were used, and with greater duration of PBMT exposure. Included studies predominantly consisted of non-randomized controlled trials (10 studies). CONCLUSIONS Hearing outcomes following PBMT appear to be superior to no PBMT for subjects with hearing loss, although higher level evidence is required to verify this. PBMT enables concentrated, focused delivery of light therapy to the inner ear through a non-invasive manner with minimal side effects. As a result of heterogeneity in reporting PBMT parameters and outcomes across the included studies, direct comparison is challenging.
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Affiliation(s)
- Yasmin Nikookam
- University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Birmingham, UK
| | - Nawal Zia
- University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Birmingham, UK
| | - Andrew Lotfallah
- University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Birmingham, UK
| | - Jameel Muzaffar
- University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Birmingham, UK
- University of Cambridge, Department of Clinical Neurosciences, Addenbrooke's Health Campus, Cambridge, UK
| | - Jennifer Davis-Manders
- University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Birmingham, UK
| | - Peter Kullar
- University of Cambridge, Department of Clinical Neurosciences, Addenbrooke's Health Campus, Cambridge, UK
| | - Matthew Smith
- University of Cambridge, Department of Clinical Neurosciences, Addenbrooke's Health Campus, Cambridge, UK
| | - Gemma Bale
- Department of Physics, Cavendish Laboratory, Cambridge, UK
- Electrical Engineering, Cambridge, UK
| | | | - Richard Irving
- University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Birmingham, UK
| | - Dan Jiang
- Guy's and St Thomas' NHS Foundation Trust, Hearing Implant Centre, St. Thomas' Hospital, London, UK
- King's College London, Centre for Craniofacial and Regenerative Biology, London, UK
| | - Manohar Bance
- University of Cambridge, Department of Clinical Neurosciences, Addenbrooke's Health Campus, Cambridge, UK
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Jang MW, Lim J, Park MG, Lee JH, Lee CJ. Active role of glia-like supporting cells in the organ of Corti: Membrane proteins and their roles in hearing. Glia 2022; 70:1799-1825. [PMID: 35713516 DOI: 10.1002/glia.24229] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 05/23/2022] [Accepted: 05/30/2022] [Indexed: 12/13/2022]
Abstract
The organ of Corti, located in the cochlea in the inner ear, is one of the major sensory organs involved in hearing. The organ of Corti consists of hair cells, glia-like supporting cells, and the cochlear nerve, which work in harmony to receive sound from the outer ear and transmit auditory signals to the cochlear nucleus in the auditory ascending pathway. In this process, maintenance of the endocochlear potential, with a high potassium gradient and clearance of electrolytes and biochemicals in the inner ear, is critical for normal sound transduction. There is an emerging need for a thorough understanding of each cell type involved in this process to understand the sophisticated mechanisms of the organ of Corti. Hair cells have long been thought to be active, playing a primary role in the cochlea in actively detecting and transmitting signals. In contrast, supporting cells are thought to be silent and function to support hair cells. However, growing lines of evidence regarding the membrane proteins that mediate ionic movement in supporting cells have demonstrated that supporting cells are not silent, but actively play important roles in normal signal transduction. In this review, we summarize studies that characterize diverse membrane proteins according to the supporting cell subtypes involved in cochlear physiology and hearing. This review contributes to a better understanding of supporting cell functions and facilitates the development of potential therapeutic tools for hearing loss.
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Affiliation(s)
- Minwoo Wendy Jang
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - Jiwoon Lim
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea.,IBS School, University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Mingu Gordon Park
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - Jae-Hun Lee
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - C Justin Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea.,IBS School, University of Science and Technology (UST), Daejeon, Republic of Korea
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Rhee CK, Chang SY. Combination photobiomodulation/N-acetyl-L-cysteine treatment appears to mitigate hair cell loss associated with noise-induced hearing loss in rats. Lasers Med Sci 2021; 36:1941-1947. [PMID: 33822307 DOI: 10.1007/s10103-021-03304-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 03/22/2021] [Indexed: 11/25/2022]
Abstract
Sensorineural hearing loss is an intractable disease. Acoustic overstimulation creates hearing loss; many patients exhibit social and emotional dysfunctions. In a model of noise-induced hearing loss (NIHL), low-level laser photobiomodulation (PBM) at a near-infrared wavelength significantly improved auditory brainstem response (ABR) thresholds. In addition, both N-acetyl-L-cysteine (NAC) and acetyl-L-carnitine (ALCAR) attenuated NIHL, reducing the effects of noise trauma in the cochlea and the central auditory system. Here, we combined PBM with antioxidants to explore hearing threshold recovery and morphological hair cell changes after rats were exposed to noise. The average auditory brainstem response thresholds after PBM/NAC combination treatment were reduced from the apex to the basal turn at all of 8, 16, and 32 kHz compared to the noise-only group. The PBM/NAC combination treated group exhibited intact outer hair cells in all turns, and significantly greater hair cell numbers in the middle and basal cochlear turns, than did controls. Thus, PBM/NAC treatment may prevent hearing dysfunction caused by NIHL.
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Affiliation(s)
- Chung-Ku Rhee
- Department of Otolaryngology-Head & Neck Surgery, College of Medicine, Dankook University, 119 Dandae-ro, Cheonan, 31116, Republic of Korea
| | - So-Young Chang
- Beckman Laser Institute Korea, Dankook University, 119 Dandae-ro, Cheonan, 31116, Republic of Korea.
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Lee JH, Ji SH, Jung JY, Lee MY, Lee CK. High Blood Glucose Levels Affect Auditory Brainstem Responses after Acoustic Overexposure in Rats. Audiol Neurootol 2021; 26:257-264. [PMID: 33735864 DOI: 10.1159/000511448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 09/08/2020] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Diabetes mellitus (DM) is a systemic disease characterized by hyperglycemia and several pathological changes. DM-related hearing dysfunctions are associated with histological changes. Here, we explore hearing function and synaptic changes in the inner hair cells (IHCs) of rats with streptozotocin (STZ)-induced diabetes. METHODS STZ was injected to trigger diabetes. Rats with DM were exposed to narrow-band noise (105 dB SPL) for 2 h, and hearing function was analyzed 1, 3, 7, and 14 days later. Both the hearing threshold and the peak 1 amplitude of the tone auditory brainstem response were assessed. After the last functional test, animals were sacrificed for histological evaluation. RESULTS We found no changes in the baseline hearing threshold; however, the peak 1 amplitude at the low frequency (4 kHz) was significantly higher in both DM groups than in the control groups. The hearing threshold had not fully recovered at 14 days after diabetic rats were exposed to noise. The peak 1 amplitude at the higher frequencies (16 and 32 kHz) was significantly larger in both DM groups than in the control groups. The histological analysis revealed that the long-term DM group had significantly more synapses in the 16 kHz region than the other groups. CONCLUSIONS We found that high blood glucose levels increased peak 1 amplitudes without changing the hearing threshold. Diabetic rats were less resilient in threshold changes and were less vulnerable to peak 1 amplitude and synaptic damage than control animals.
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Affiliation(s)
- Jae-Hun Lee
- Beckman Laser Institute Korea, College of Medicine, Dankook University, Cheonan, Republic of Korea.,Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Dankook University, Cheonan, Republic of Korea
| | - Sang Hee Ji
- Department of Otolaryngology-Head and Neck Surgery, Soonchunhyang University Cheonan Hospital, Soonchunhyang University, College of Medicine, Cheonan, Republic of Korea
| | - Jae Yun Jung
- Beckman Laser Institute Korea, College of Medicine, Dankook University, Cheonan, Republic of Korea.,Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Dankook University, Cheonan, Republic of Korea
| | - Min Young Lee
- Beckman Laser Institute Korea, College of Medicine, Dankook University, Cheonan, Republic of Korea, .,Department of Otolaryngology-Head and Neck Surgery, College of Medicine, Dankook University, Cheonan, Republic of Korea,
| | - Chi-Kyou Lee
- Department of Otolaryngology-Head and Neck Surgery, Soonchunhyang University Cheonan Hospital, Soonchunhyang University, College of Medicine, Cheonan, Republic of Korea
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Ferreira MC, de Matos IL, de Toledo IP, Honório HM, Mondelli MFCG. Effects of Low-Level Laser Therapy as a Therapeutic Strategy for Patients With Tinnitus: A Systematic Review. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2021; 64:279-298. [PMID: 33375822 DOI: 10.1044/2020_jslhr-20-00066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Purpose This systematic review aimed to analyze the effects of low-level laser therapy (LLLT) on the severity of tinnitus when compared to no therapy or other modalities of therapies. Method A systematic review protocol was registered at the International Prospective Register of Systematic Reviews (PROSPERO) under the Registration Number CRD42019119376. A search was performed in each of the following databases: EMBASE, LILACS, PubMed, Science Direct, Scopus, Web of Science, Google Scholar, and ProQuest. The inclusion criteria consisted of studies in adults over 16 years of age, randomized clinical trials in which subjects presented chronic (≥ 6 months) and subjective tinnitus (unilateral or bilateral) as well as with or without bilateral sensorineural hearing loss, and studies that used only LLLT for treatment of tinnitus compared to no-therapy group or other modalities of therapy. No language or time restrictions were stipulated. The references were managed by Endnote Web and Rayyan QCRI. Results After the screening process, seven studies remained that attained the eligibility criteria. Regarding the risk of bias, only one study was categorized as low risk of bias; the six remaining studies were classified as moderate risk of bias. The seven included studies mainly assessed the LLLT effects on tinnitus by Visual Analogue Scale, Tinnitus Handicap Inventory, pitch and loudness matching, minimum masking level, and pure-tone audiometry. All the seven selected studies found different degrees of significant results regarding tinnitus severity; however, there was no consensus among the results. Conclusion Even though the LLLT showed positive effects in the tinnitus severity in some studies, it is not possible yet to make any recommendation over its uses for the treatment of tinnitus severity.
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Affiliation(s)
- Maria Carolina Ferreira
- Speech Therapy Program, Bauru School of Dentistry, University of Sao Paulo, Sao Paulo, Brazil
| | - Izabella Lima de Matos
- Speech Therapy Program, Bauru School of Dentistry, University of Sao Paulo, Sao Paulo, Brazil
| | | | - Heitor Marques Honório
- Department of Pediatric Dentistry, Orthodontics and Community Health, Bauru School of Dentistry, University of Sao Paulo, Sao Paulo, Brazil
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Lee JH, Lee MY, Choi JE, Jung JY. Auditory Brainstem Response to Paired Click Stimulation as an Indicator of Peripheral Synaptic Health in Noise-Induced Cochlear Synaptopathy. Front Neurosci 2021; 14:596670. [PMID: 33505238 PMCID: PMC7830024 DOI: 10.3389/fnins.2020.596670] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/03/2020] [Indexed: 11/22/2022] Open
Abstract
Introduction A defect in the cochlear afferent synapse between the inner hair cells and spiral ganglion neurons, after noise exposure, without changes in the hearing threshold has been reported. Animal studies on auditory evoked potentials demonstrated changes in the auditory brainstem response (ABR) measurements of peak I amplitude and the loss of synapses, which affect the temporal resolution of complex sounds. Human studies of auditory evoked potential have reported ambiguous results regarding the relationship between peak I amplitude and noise exposure. Paired click stimuli have been used to investigate the temporal processing abilities of humans and animals. In this study, we investigated the utility of measuring auditory evoked potentials in response to paired click stimuli to assess the temporal processing function of ribbon synapses in noise-induced cochlear synaptopathy. Materials and Methods Twenty-two Sprague Dawley rats were used in this study, and synaptopathy was induced by narrow-band noise exposure (16 kHz with 1 kHz bandwidth, 105 dB sound pressure level for 2 h). ABRs to tone and paired click stimuli were measured before and 1, 3, 7, and 14 days after noise exposure. For histological analyses, hair cells and ribbon synapses were immunostained and the synapses quantified. The relationships among ABR peak I amplitude, number of synapses, and ABR to paired click stimuli were examined. Results Our results showed that ABR thresholds increase 1 day after noise exposure but fully recover to baseline levels after 14 days. Further, we demonstrated test frequency-dependent decreases in peak I amplitude and the number of synapses after noise exposure. These decreases were statistically significant at frequencies of 16 and 32 kHz. However, the ABR recovery threshold to paired click stimuli increased, which represent deterioration in the ability of temporal auditory processing. Our results indicate that the ABR recovery threshold is highly correlated with ABR peak I amplitude after noise exposure. We also established a direct correlation between the ABR recovery threshold and histological findings. Conclusion The result from this study suggests that in animal studies, the ABR to paired click stimuli along with peak I amplitude has potential as an assessment tool for hidden hearing loss.
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Affiliation(s)
- Jae-Hun Lee
- Department of Otolaryngology Head and Neck Surgery College of Medicine, Dankook University, Cheonan, South Korea
| | - Min Young Lee
- Department of Otolaryngology Head and Neck Surgery College of Medicine, Dankook University, Cheonan, South Korea.,Department of Otolaryngology Head and Neck Surgery, Dankook University Hospital, Cheonan, South Korea
| | - Ji Eun Choi
- Department of Otolaryngology Head and Neck Surgery College of Medicine, Dankook University, Cheonan, South Korea.,Department of Otolaryngology Head and Neck Surgery, Dankook University Hospital, Cheonan, South Korea
| | - Jae Yun Jung
- Department of Otolaryngology Head and Neck Surgery College of Medicine, Dankook University, Cheonan, South Korea.,Department of Otolaryngology Head and Neck Surgery, Dankook University Hospital, Cheonan, South Korea
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Protection of Cochlear Ribbon Synapses and Prevention of Hidden Hearing Loss. Neural Plast 2020; 2020:8815990. [PMID: 33204247 PMCID: PMC7652619 DOI: 10.1155/2020/8815990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 10/08/2020] [Accepted: 10/21/2020] [Indexed: 01/21/2023] Open
Abstract
In the auditory system, ribbon synapses are vesicle-associated structures located between inner hair cells (IHCs) and spiral ganglion neurons that are implicated in the modulation of trafficking and fusion of synaptic vesicles at the presynaptic terminals. Synapse loss may result in hearing loss and difficulties with understanding speech in a noisy environment. This phenomenon happens without permanent hearing loss; that is, the cochlear synaptopathy is "hidden." Recent studies have reported that synapse loss might be critical in the pathogenesis of hidden hearing loss. A better understanding of the molecular mechanisms of the formation, structure, regeneration, and protection of ribbon synapses will assist in the design of potential therapeutic strategies. In this review, we describe and summarize the following aspects of ribbon synapses: (1) functional and structural features, (2) potential mechanisms of damage, (3) therapeutic research on protecting the synapses, and (4) the role of synaptic regeneration in auditory neuropathy and the current options for synapse rehabilitation.
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Basta D, Gröschel M, Strübing I, Boyle P, Fröhlich F, Ernst A, Seidl R. Near-infrared-light pre-treatment attenuates noise-induced hearing loss in mice. PeerJ 2020; 8:e9384. [PMID: 32596055 PMCID: PMC7305775 DOI: 10.7717/peerj.9384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 05/28/2020] [Indexed: 12/02/2022] Open
Abstract
Noise induced hearing loss (NIHL) is accompanied by a reduction of cochlear hair cells and spiral ganglion neurons. Different approaches have been applied to prevent noise induced apoptosis / necrosis. Physical intervention is one technique currently under investigation. Specific wavelengths within the near-infrared light (NIR)-spectrum are known to influence cytochrome-c-oxidase activity, which leads in turn to a decrease in apoptotic mechanisms. It has been shown recently that NIR can significantly decrease the cochlear hair cell loss if applied daily for 12 days after a noise exposure. However, it is still unclear if a single NIR-treatment, just before a noise exposure, could induce similar protective effects. Therefore, the present study was conducted to investigate the effect of a single NIR-pre-treatment aimed at preventing or limiting NIHL. The cochleae of adult NMRI-mice were pre-treated with NIR-light (808 nm, 120 mW) for 5, 10, 20, 30 or 40 minutes via the external ear canal. All animals were noised exposed immediately after the pre-treatment by broad band noise (5–20 kHz) for 30 minutes at 115 dB SPL. Frequency specific ABR-recordings to determine auditory threshold shift were carried out before the pre-treatment and two weeks after the noise exposure. The amplitude increase for wave IV and cochlear hair cell loss were determined. A further group of similar mice was noise exposed only and served as a control for the NIR pre-exposed groups. Two weeks after noise exposure, the ABR threshold shifts of NIR-treated animals were significantly lower (p < 0.05) than those of the control animals. The significance was at three frequencies for the 5-minute pre-treatment group and across the entire frequency range for all other treatment groups. Due to NIR light, the amplitude of wave four deteriorates significantly less after noise exposure than in controls. The NIR pre-treatment had no effect on the loss of outer hair cells, which was just as high with or without NIR-light pre-exposure. Relative to the entire number of outer hair cells across the whole cochlea, outer hair cell loss was rather negligible. No inner hair cell loss whatever was detected. Our results suggest that a single NIR pre-treatment induces a very effective protection of cochlear structures from noise exposure. Pre-exposure of 10 min seems to emerge as the optimal dosage for our experimental setup. A saturated effect occurred with higher dosage-treatments. These results are relevant for protection of residual hearing in otoneurosurgery such as cochlear implantation.
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Affiliation(s)
- Dietmar Basta
- Department of ENT at ukb, Charité Medical School, University of Berlin, Berlin, Germany
| | - Moritz Gröschel
- Department of ENT at ukb, Charité Medical School, University of Berlin, Berlin, Germany
| | - Ira Strübing
- Department of ENT at ukb, Charité Medical School, University of Berlin, Berlin, Germany
| | | | - Felix Fröhlich
- Department of ENT at ukb, Charité Medical School, University of Berlin, Berlin, Germany
| | - Arne Ernst
- Department of ENT at ukb, Charité Medical School, University of Berlin, Berlin, Germany
| | - Rainer Seidl
- Department of ENT at ukb, Charité Medical School, University of Berlin, Berlin, Germany
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Morgan D, Arteaga A, Bosworth N, Proctor G, Vetter D, Lobarinas E, Spankovich C. Repeated temporary threshold shift and changes in cochlear and neural function. Hear Res 2019; 381:107780. [DOI: 10.1016/j.heares.2019.107780] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 08/02/2019] [Accepted: 08/06/2019] [Indexed: 11/28/2022]
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