title: Chronic exposure to low frequency noise at moderate levels causes impaired balance in mice.
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.
authors: Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Kasugai, Aichi, Japan.
authors: Haruka
authors: H
authors: Tamura
authors: Nobutaka
authors: N
authors: Ohgami
authors: Ichiro
authors: I
authors: Yajima
authors: Machiko
authors: M
authors: Iida
authors: Kyoko
authors: K
authors: Ohgami
authors: Noriko
authors: N
authors: Fujii
authors: Hiroyuki
authors: H
authors: Itabe
authors: Tastuya
authors: T
authors: Kusudo
authors: Hitoshi
authors: H
authors: Yamashita
authors: Masashi
authors: M
authors: Kato
mesh_terms: D000818:Animals; D002452:Cell Count; D055615:Electrical Equipment and Supplies; D004781:Environmental Exposure; D005684:Gait / Q000502:physiology; D018069:Hair Cells, Vestibular / Q000473:pathology; D006801:Humans; D051379:Mice; D008813:Mice, Inbred ICR; D009622:Noise; D018384:Oxidative Stress; D004856:Postural Balance / Q000502:physiology*; D045442:Rotarod Performance Test