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Tan HT, Smith PF, Zheng Y. Time-dependent effects of acoustic trauma and tinnitus on extracellular levels of amino acids in the inferior colliculus of rats. Hear Res 2024; 443:108948. [PMID: 38219615 DOI: 10.1016/j.heares.2024.108948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/19/2023] [Accepted: 01/02/2024] [Indexed: 01/16/2024]
Abstract
Chronic tinnitus is a debilitating condition with very few management options. Acoustic trauma that causes tinnitus has been shown to induce neuronal hyperactivity in multiple brain areas in the auditory pathway, including the inferior colliculus. This neuronal hyperactivity could be attributed to an imbalance between excitatory and inhibitory neurotransmission. However, it is not clear how the levels of neurotransmitters, especially neurotransmitters in the extracellular space, change over time following acoustic trauma and the development of tinnitus. In the present study, a range of amino acids were measured in the inferior colliculus of rats during acoustic trauma as well as at 1 week and 5 months post-trauma using in vivo microdialysis and high-performance liquid chromatography. Amino acid levels in response to sound stimulation were also measured at 1 week and 5 months post-trauma. It was found that unilateral exposure to a 16 kHz pure tone at 115 dB SPL for 1 h caused immediate hearing loss in all the animals and chronic tinnitus in 58 % of the animals. Comparing to the sham condition, extracellular levels of GABA were significantly increased at both the acute and 1 week time points after acoustic trauma. However, there was no significant difference in any of the amino acid levels measured between sham, tinnitus positive and tinnitus negative animals at 5 months post-trauma. There was also no clear pattern in the relationship between neurochemical changes and sound frequency/acoustic trauma/tinnitus status, which might be due to the relatively poorer temporal resolution of the microdialysis compared to electrophysiological responses.
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Affiliation(s)
- Huey Tieng Tan
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand; Eisdell Moore Centre for Research on Hearing and Balance Disorders, University of Auckland, New Zealand
| | - Paul F Smith
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand; Eisdell Moore Centre for Research on Hearing and Balance Disorders, University of Auckland, New Zealand
| | - Yiwen Zheng
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand; Eisdell Moore Centre for Research on Hearing and Balance Disorders, University of Auckland, New Zealand.
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Lue PY, Oliver MH, Neeff M, Thorne PR, Suzuki-Kerr H. Sheep as a large animal model for hearing research: comparison to common laboratory animals and humans. Lab Anim Res 2023; 39:31. [PMID: 38012676 PMCID: PMC10680324 DOI: 10.1186/s42826-023-00182-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 11/29/2023] Open
Abstract
Sensorineural hearing loss (SNHL), caused by pathology in the cochlea, is the most common type of hearing loss in humans. It is generally irreversible with very few effective pharmacological treatments available to prevent the degenerative changes or minimise the impact. Part of this has been attributed to difficulty of translating "proof-of-concept" for novel treatments established in small animal models to human therapies. There is an increasing interest in the use of sheep as a large animal model. In this article, we review the small and large animal models used in pre-clinical hearing research such as mice, rats, chinchilla, guinea pig, rabbit, cat, monkey, dog, pig, and sheep to humans, and compare the physiology, inner ear anatomy, and some of their use as model systems for SNHL, including cochlear implantation surgeries. Sheep have similar cochlear anatomy, auditory threshold, neonatal auditory system development, adult and infant body size, and number of birth as humans. Based on these comparisons, we suggest that sheep are well-suited as a potential translational animal model that bridges the gap between rodent model research to the clinical use in humans. This is especially in areas looking at changes across the life-course or in specific areas of experimental investigation such as cochlear implantation and other surgical procedures, biomedical device development and age-related sensorineural hearing loss research. Combined use of small animals for research that require higher throughput and genetic modification and large animals for medical translation could greatly accelerate the overall translation of basic research in the field of auditory neuroscience from bench to clinic.
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Affiliation(s)
- Po-Yi Lue
- Department of Physiology, The University of Auckland, Auckland, New Zealand
- Eisdell Moore Centre, The University of Auckland, Auckland, New Zealand
| | - Mark H Oliver
- Liggins Institute, The University of Auckland, Auckland, New Zealand
- Ngapouri Research Farm Laboratory, University of Auckland, Waiotapu, New Zealand
| | - Michel Neeff
- Department of Physiology, The University of Auckland, Auckland, New Zealand
- Department of Surgery, Auckland District Health Board, Auckland, New Zealand
| | - Peter R Thorne
- Department of Physiology, The University of Auckland, Auckland, New Zealand
- Eisdell Moore Centre, The University of Auckland, Auckland, New Zealand
- Section of Audiology, The University of Auckland, Auckland, New Zealand
| | - Haruna Suzuki-Kerr
- Department of Physiology, The University of Auckland, Auckland, New Zealand.
- Eisdell Moore Centre, The University of Auckland, Auckland, New Zealand.
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Domarecka E, Szczepek AJ. Universal Recommendations on Planning and Performing the Auditory Brainstem Responses (ABR) with a Focus on Mice and Rats. Audiol Res 2023; 13:441-458. [PMID: 37366685 DOI: 10.3390/audiolres13030039] [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: 04/24/2023] [Revised: 05/17/2023] [Accepted: 05/29/2023] [Indexed: 06/28/2023] Open
Abstract
Translational audiology research aims to transfer basic research findings into practical clinical applications. While animal studies provide essential knowledge for translational research, there is an urgent need to improve the reproducibility of data derived from these studies. Sources of variability in animal research can be grouped into three areas: animal, equipment, and experimental. To increase standardization in animal research, we developed universal recommendations for designing and conducting studies using a standard audiological method: auditory brainstem response (ABR). The recommendations are domain-specific and are intended to guide the reader through the issues that are important when applying for ABR approval, preparing for, and conducting ABR experiments. Better experimental standardization, which is the goal of these guidelines, is expected to improve the understanding and interpretation of results, reduce the number of animals used in preclinical studies, and improve the translation of knowledge to the clinic.
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Affiliation(s)
- Ewa Domarecka
- Department of Otorhinolaryngology, Head and Neck Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Agnieszka J Szczepek
- Department of Otorhinolaryngology, Head and Neck Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
- Faculty of Medicine and Health Sciences, University of Zielona Gora, 65-046 Zielona Gora, Poland
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Krajnak K, Waugh S, Welcome D, Xu XS, Warren C, McKinney W, Dong RG. Effects of whole-body vibration on reproductive physiology in a rat model of whole-body vibration. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2022; 85:953-971. [PMID: 36165131 PMCID: PMC9885295 DOI: 10.1080/15287394.2022.2128954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Findings from epidemiological studies suggest that occupational exposure to whole-body vibration (WBV) may increase the risk of miscarriage and contribute to a reduction in fertility rates in both men and women. However, workers exposed to WBV may also be exposed to other risk factors that contribute to reproductive dysfunction. The goal of this experiment was to examine the effects of WBV on reproductive physiology in a rat model. Male and female rats were exposed to WBV at the resonant frequency of the torso (31.5 Hz, 0.3 g amplitude) for 4 hr/day for 10 days. WBV exposure resulted in a significant reduction in number of developing follicles, and decrease in circulating estradiol concentrations, ovarian luteinizing hormone receptor protein levels, and marked changes in transcript levels for several factors involved in follicular development, cell cycle, and steroidogenesis. In males, WBV resulted in a significant reduction in spermatids and circulating prolactin levels, elevation in number of males having higher circulating testosterone concentrations, and marked alterations in levels of transcripts associated with oxidative stress, inflammation, and factors involved in regulating the cell cycle. Based upon these findings data indicate that occupational exposure to WBV contributes to adverse alterations in reproductive physiology in both genders that may lead to reduction in fertility.
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Affiliation(s)
- K Krajnak
- Physical Effects Research Branch, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - S Waugh
- Physical Effects Research Branch, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - D Welcome
- Physical Effects Research Branch, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - X S Xu
- Physical Effects Research Branch, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - C Warren
- Physical Effects Research Branch, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - W McKinney
- Physical Effects Research Branch, National Institute for Occupational Safety and Health, Morgantown, West Virginia
| | - R G Dong
- Physical Effects Research Branch, National Institute for Occupational Safety and Health, Morgantown, West Virginia
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Kiefer L, Koch L, Merdan-Desik M, Gaese BH, Nowotny M. Comparing the electrophysiological effects of traumatic noise exposure between rodents. J Neurophysiol 2022; 127:452-462. [PMID: 35020518 DOI: 10.1152/jn.00081.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Noise-induced hearing deficits are important health problems in the industrialized world. As the underlying physiological dysfunctions are not well understood, research in suitable animal models is urgently needed. Three rodent species (Mongolian gerbil, rat and mouse) were studied to compare the temporal dynamics of noise-induced hearing loss after identical procedures of noise exposure. Auditory brainstem responses (ABRs) were measured before, during and up to eight weeks after noise exposure for threshold determination and ABR waveform analysis. Trauma induction with stepwise increasing sound pressure level was interrupted by five interspersed ABR measurements. Comparing short- and long-term dynamics underlying the following noise-induced hearing loss revealed diverging time courses between the three species. Hearing loss occurred early on during noise exposure in all three rodent species at or above trauma frequency. Initial noise level (105 dB SPL) was most effective in rats while the delayed level-increase to 115 dB SPL affected mice much stronger. Induced temporary threshold shifts in rats and mice were larger in animals with lower pre-trauma ABR thresholds. The increase in activity (gain) along the auditory pathway was derived by comparing the amplitudes of short- and long-latency ABR waveform components. Directly after trauma, significant effects were found for rats (decreasing gain) and mice (increasing gain) while gerbils revealed high individual variability in gain changes. Taken together, our comparative study revealed pronounced species-specific differences in the development of noise-induced hearing loss and the related processing along the auditory pathway.
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Affiliation(s)
- Lenneke Kiefer
- Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany
| | - Lisa Koch
- Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany
| | - Melisa Merdan-Desik
- Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany.,Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University, Jena, Germany
| | - Bernhard H Gaese
- Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany
| | - Manuela Nowotny
- Institute of Cell Biology and Neuroscience, Goethe University, Frankfurt am Main, Germany.,Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University, Jena, Germany
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