1
|
Mao B, Wang Y, Balasubramanian T, Urioste R, Wafa T, Fitzgerald TS, Haraczy SJ, Edwards-Hollingsworth K, Sayyid ZN, Wilder D, Sajja VSSS, Wei Y, Arun P, Gist I, Cheng AG, Long JB, Kelley MW. Assessment of auditory and vestibular damage in a mouse model after single and triple blast exposures. Hear Res 2021; 407:108292. [PMID: 34214947 DOI: 10.1016/j.heares.2021.108292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/17/2021] [Accepted: 06/02/2021] [Indexed: 12/18/2022]
Abstract
The use of explosive devices in war and terrorism has increased exposure to concussive blasts among both military personnel and civilians, which can cause permanent hearing and balance deficits that adversely affect survivors' quality of life. Significant knowledge gaps on the underlying etiology of blast-induced hearing loss and balance disorders remain, especially with regard to the effect of blast exposure on the vestibular system, the impact of multiple blast exposures, and long-term recovery. To address this, we investigated the effects of blast exposure on the inner ear using a mouse model in conjunction with a high-fidelity blast simulator. Anesthetized animals were subjected to single or triple blast exposures, and physiological measurements and tissue were collected over the course of recovery for up to 180 days. Auditory brainstem responses (ABRs) indicated significantly elevated thresholds across multiple frequencies. Limited recovery was observed at low frequencies in single-blasted mice. Distortion Product Otoacoustic Emissions (DPOAEs) were initially absent in all blast-exposed mice, but low-amplitude DPOAEs could be detected at low frequencies in some single-blast mice by 30 days post-blast, and in some triple-blast mice at 180 days post-blast. All blast-exposed mice showed signs of Tympanic Membrane (TM) rupture immediately following exposure and loss of outer hair cells (OHCs) in the basal cochlear turn. In contrast, the number of Inner Hair Cells (IHCs) and spiral ganglion neurons was unchanged following blast-exposure. A significant reduction in IHC pre-synaptic puncta was observed in the upper turns of blast-exposed cochleae. Finally, we found no significant loss of utricular hair cells or changes in vestibular function as assessed by vestibular evoked potentials. Our results suggest that (1) blast exposure can cause severe, long-term hearing loss which may be partially due to slow TM healing or altered mechanical properties of healed TMs, (2) traumatic levels of sound can still reach the inner ear and cause basal OHC loss despite middle ear dysfunction caused by TM rupture, (3) blast exposure may result in synaptopathy in humans, and (4) balance deficits after blast exposure may be primarily due to traumatic brain injury, rather than damage to the peripheral vestibular system.
Collapse
Affiliation(s)
- Beatrice Mao
- Section on Developmental Neuroscience, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA.
| | - Ying Wang
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
| | - Tara Balasubramanian
- Section on Developmental Neuroscience, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Rodrigo Urioste
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Talah Wafa
- Mouse Auditory Testing Core Facility, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Tracy S Fitzgerald
- Mouse Auditory Testing Core Facility, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Scott J Haraczy
- Section on Developmental Neuroscience, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Kamren Edwards-Hollingsworth
- Section on Developmental Neuroscience, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Zahra N Sayyid
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Donna Wilder
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Venkata Siva Sai Sujith Sajja
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Yanling Wei
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Peethambaran Arun
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Irene Gist
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Alan G Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Joseph B Long
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
| | - Matthew W Kelley
- Section on Developmental Neuroscience, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|