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Ohgami N, Oshino R, Ninomiya H, Li X, Kato M, Yajima I, Kato M. Risk Assessment of Neonatal Exposure to Low Frequency Noise Based on Balance in Mice. Front Behav Neurosci 2017; 11:30. [PMID: 28275341 PMCID: PMC5319995 DOI: 10.3389/fnbeh.2017.00030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 02/09/2017] [Indexed: 11/13/2022] Open
Abstract
General electric devices and ventilation systems are known to generate low frequency noise (LFN) with frequencies of <100 Hz. Previous studies showed that exposure to LFN caused impairments of balance in humans and mice during adulthood. On the other hand, a previous study showed that noise levels in the neonatal intensive care unit (NICU) were greater than those in general home or office environments. Therefore, it is possible that neonates have a potential risk to be exposed to LFN in the NICU. However, the risk of neonatal exposure to LFN remains unclear in humans and mice. In this study, male ICR mice were exposed to LFN at 100 Hz for 4 weeks after birth and then subjected to rotarod and beam crossing tests in order to assess LFN-mediated risk of imbalance during the neonatal period. Exposure to LFN at 70 dB, but not exposure to LFN up to 60 dB, during the neonatal period significantly decreased performance scores for rotarod and beam crossing tests compared to the scores of the control group. The number of calbindin-positive hair cells in the saccule and utricle was decreased in mice exposed to LFN at 70 dB for 4 weeks in the neonatal phase. Cessation of exposure for 10 weeks did not result in recovery of the decreased performance in rotarod and beam crossing tests. Thus, our results suggest that 70 dB is a possible threshold for exposure to LFN for 4 weeks during the neonatal period causing unrecoverable imbalance in mice.
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Affiliation(s)
- Nobutaka Ohgami
- Department of Occupational and Environmental Health, Nagoya University Graduate School of MedicineNagoya, Japan; Nutritional Health Science Research Center, Chubu UniversityKasugai, Japan
| | - Reina Oshino
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Hiromasa Ninomiya
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Xiang Li
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Masashi Kato
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology Nagoya, Japan
| | - Ichiro Yajima
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine Nagoya, Japan
| | - Masashi Kato
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine Nagoya, Japan
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Tamura H, Ohgami N, Yajima I, Iida M, Ohgami K, Fujii N, Itabe H, Kusudo T, Yamashita H, Kato M. Chronic exposure to low frequency noise at moderate levels causes impaired balance in mice. PLoS One 2012; 7:e39807. [PMID: 22768129 PMCID: PMC3387207 DOI: 10.1371/journal.pone.0039807] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 05/26/2012] [Indexed: 11/19/2022] Open
Abstract
We are routinely exposed to low frequency noise (LFN; below 0.5 kHz) at moderate levels of 60-70 dB sound pressure level (SPL) generated from various sources in occupational and daily environments. LFN has been reported to affect balance in humans. However, there is limited information about the influence of chronic exposure to LFN at moderate levels for balance. In this study, we investigated whether chronic exposure to LFN at a moderate level of 70 dB SPL affects the vestibule, which is one of the organs responsible for balance in mice. Wild-type ICR mice were exposed for 1 month to LFN (0.1 kHz) and high frequency noise (HFN; 16 kHz) at 70 dB SPL at a distance of approximately 10-20 cm. Behavior analyses including rotarod, beam-crossing and footprint analyses showed impairments of balance in LFN-exposed mice but not in non-exposed mice or HFN-exposed mice. Immunohistochemical analysis showed a decreased number of vestibular hair cells and increased levels of oxidative stress in LFN-exposed mice compared to those in non-exposed mice. Our results suggest that chronic exposure to LFN at moderate levels causes impaired balance involving morphological impairments of the vestibule with enhanced levels of oxidative stress. Thus, the results of this study indicate the importance of considering the risk of chronic exposure to LFN at a moderate level for imbalance.
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Affiliation(s)
- Haruka Tamura
- Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi, Japan
| | - Nobutaka Ohgami
- Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi, Japan
| | - Ichiro Yajima
- Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi, Japan
| | - Machiko Iida
- Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi, Japan
| | - Kyoko Ohgami
- Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi, Japan
| | - Noriko Fujii
- Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan, Osaka, Japan
| | - Hiroyuki Itabe
- Department of Biological Chemistry, Showa University School of Pharmacy, Hatanodai, Shinagawa-ku, Tokyo, Japan
| | - Tastuya Kusudo
- Unit of Molecular Biology, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi, Japan
| | - Hitoshi Yamashita
- Unit of Molecular Biology, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi, Japan
| | - Masashi Kato
- Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi, Japan
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