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Wu PZ, O'Malley JT, Liberman MC. Neural Degeneration in Normal-Aging Human Cochleas: Machine-Learning Counts and 3D Mapping in Archival Sections. J Assoc Res Otolaryngol 2023; 24:499-511. [PMID: 37957485 PMCID: PMC10695900 DOI: 10.1007/s10162-023-00909-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 09/03/2023] [Indexed: 11/15/2023] Open
Abstract
Quantifying the survival patterns of spiral ganglion cells (SGCs), the cell bodies of auditory-nerve fibers, is critical to studies of sensorineural hearing loss, especially in human temporal bones. The classic method of manual counting is tedious, and, although stereology approaches can be faster, they can only be used to estimate total cell numbers per cochlea. Here, a machine-learning algorithm that automatically identifies, counts, and maps the SGCs in digitized images of semi-serial human temporal-bone sections not only speeds the analysis, with no loss of accuracy, but also allows 3D visualization of the SGCs and fine-grained mapping to cochlear frequency. Applying the algorithm to 62 normal-aging human ears shows significantly faster degeneration of SGCs in the basal than the apical half of the cochlea. Comparison to fiber counts in the same ears shows that the fraction of surviving SGCs lacking a peripheral axon steadily increases with age, reaching more than 50% in the apical cochlea and almost 66% in basal regions.
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Affiliation(s)
- Pei-Zhe Wu
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114-3096, USA.
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02115, USA.
| | - Jennifer T O'Malley
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114-3096, USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02115, USA
| | - M Charles Liberman
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114-3096, USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA, 02115, USA
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Li P, Li S, Wang L, Li H, Wang Y, Liu H, Wang X, Zhu X, Liu Z, Ye F, Zhang Y. Mitochondrial dysfunction in hearing loss: Oxidative stress, autophagy and NLRP3 inflammasome. Front Cell Dev Biol 2023; 11:1119773. [PMID: 36891515 PMCID: PMC9986271 DOI: 10.3389/fcell.2023.1119773] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/07/2023] [Indexed: 02/22/2023] Open
Abstract
Sensorineural deafness becomes an inevitable worldwide healthy problem, yet the current curative therapy is limited. Emerging evidences demonstrate mitochondrial dysfunction plays a vital role of in the pathogenesis of deafness. Reactive oxygen species (ROS)-induced mitochondrial dysfunction combined with NLRP3 inflammasome activation is involved in cochlear damage. Autophagy not only clears up undesired proteins and damaged mitochondria (mitophagy), but also eliminate excessive ROS. Appropriate enhancement of autophagy can reduce oxidative stress, inhibit cell apoptosis, and protect auditory cells. In addition, we further discuss the interplays linking ROS generation, NLRP3 inflammasome activation, and autophagy underlying the pathogenesis of deafness, including ototoxic drugs-, noise- and aging-related hearing loss.
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Affiliation(s)
- Peipei Li
- Department of Integrated Traditional and Western Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China
| | - Shen Li
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Le Wang
- Department of Otology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Hongmin Li
- Department of Otology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yang Wang
- Department of Otology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Hongbing Liu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xin Wang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiaodan Zhu
- Department of Otology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zhangsuo Liu
- Department of Integrated Traditional and Western Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Henan Province Research Center for Kidney Disease, Zhengzhou, China
| | - Fanglei Ye
- Department of Otology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yuan Zhang
- Department of Otology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Doostkam A, Mirkhani H, Iravani K, Karbalay-Doust S, Doosti A, Nadimi E, Pirsalami F. Controversial Role of Folic Acid on Diabetic Auditory Neuropathy. ACS Pharmacol Transl Sci 2022; 5:985-992. [PMID: 36268113 PMCID: PMC9578138 DOI: 10.1021/acsptsci.2c00140] [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: 07/13/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Diabetic auditory neuropathy (DAN) is a common complication of diabetes that seriously affects the quality of life in patients. In this study, we investigate the role of folic acid in the treatment of DAN in an experimental rat model. METHODS Thirty-two Sprague-Dawley rats were equally divided into four groups: group 1, normal; group 2, diabetic rats; and groups 3 and 4, diabetic rats treated with folic acid (40 and 80 mg/kg, respectively). We used some tools to investigate the therapeutic effect of folic acid on DAN. We evaluated auditory brain stem response (ABR), estimated the volume and number of spiral ganglion and the volume of stria vascularis and spiral ligament by the stereological method, and measured the blood levels of homocysteine (HCY), malondialdehyde (MDA), and superoxide dismutase (SOD). RESULTS Our study showed that folic acid treatment was not significantly effective in improving structural and functional disorders in DAN, even though its effectiveness in reducing HCY (P < 0.001) and MDA (P < 0.05) as oxidative biomarkers was significant. CONCLUSION Folic acid is not effective in relieving morphological and functional disorders in DAN.
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Affiliation(s)
- Aida Doostkam
- Shiraz
Nephro-Urology Research Center, Shiraz University
of Medical Sciences, Shiraz 7193635899, Iran
| | - Hossein Mirkhani
- Department
of Pharmacology, School of Medicine, Medicinal and Natural Products
Chemistry Research Center, Shiraz University
of Medical Sciences, Shiraz 7134853185, Iran
| | - Kamyar Iravani
- Department
of Otolaryngology, Otolaryngology Research Center, Shiraz University of Medical Sciences, Shiraz 71936-16641, Iran
| | - Saied Karbalay-Doust
- Department
of Anatomy, School of Medicine, Histomorphometry and Stereology Research
Center, Shiraz University of Medical Sciences, Shiraz 7134853185, Iran
| | - Afsaneh Doosti
- Department
of Audiology, School of Rehabilitation Sciences, Rehabilitation Sciences
Research Center, Shiraz University of Medical
Sciences, Shiraz 7194733669, Iran
| | - Elham Nadimi
- Histomorphometry
and Stereology Research Center, Shiraz University
of Medical Sciences, Shiraz 7134853185, Iran
| | - Fatema Pirsalami
- Department
of Pharmacology, School of Medicine, Shiraz
University of Medical Sciences, Shiraz 7134853185, Iran
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Li H, Lu M, Zhang H, Wang S, Wang F, Ma X, Liu J, Li X, Yang H, Shen H, Lv P. Downregulation of REST in the cochlea contributes to age-related hearing loss via the p53 apoptosis pathway. Cell Death Dis 2022; 13:343. [PMID: 35418568 PMCID: PMC9007975 DOI: 10.1038/s41419-022-04774-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/16/2022] [Accepted: 03/25/2022] [Indexed: 12/11/2022]
Abstract
Age-related hearing loss (AHL) is the most common sensory disorder amongst the elderly population. Although the degeneration of spiral ganglion neurons (SGNs) and hair cells (HCs) is considered to play a critical role in AHL, the mechanism has not been fully outlined. The repressor element 1-silencing transcription factor (REST) has recently been associated with mediating cell death in neurodegenerative diseases. However, whether REST induces degeneration of cochlear HCs and SGNs to contribute to AHL remains unknown. Here, we report that REST expression was decreased in HCs and SGNs in AHL mice. Conditional deletion of Rest in HCs and SGNs of 2-month-old mice resulted in hearing loss accompanied by the upregulation of p53, TNFR1(tumor necrosis factor receptor-1), and cleaved caspase-3. The p53 inhibitor pifithrin-α significantly attenuated SGN and HC damage and rescued hearing impairment in Rest cKO mice. Furthermore, downregulation of REST by H2O2 treatment induced apoptosis in the House Ear Institute Organ of Corti 1 cell, through the upregulation of p53. In contrast, overexpression of REST reversed the changes in p53 expression. In addition, REST was further shown to bind directly to the p53 promoter site, thereby inhibiting the effect of p53. Finally, in aged mice, the p53 inhibitor significantly reduced loss of HCs and SGNs, and subsequently improved hearing. In summary, our findings indicate that REST has a protective role in AHL, and that its deficiency upregulates p53 and induces cochlear cell apoptosis, which that leads to deafness.
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Mechanism and Protection of Radiotherapy Induced Sensorineural Hearing Loss for Head and Neck Cancer. BIOMED RESEARCH INTERNATIONAL 2022; 2021:3548706. [PMID: 34970625 PMCID: PMC8714384 DOI: 10.1155/2021/3548706] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/18/2021] [Accepted: 12/08/2021] [Indexed: 12/15/2022]
Abstract
Purpose Radiotherapy-induced sensorineural hearing loss (RISNHL) is a common adverse effect in patients with head and neck cancer. Given that there are few studies on the pathogenesis of RISNHL at present, we summarized the possible pathogenesis of RISNHL and possible protective measures found at present by referring to relevant literatures. Methods We performed a comprehensive literature search in the PubMed database, using keywords “sensorineural hearing loss,” “radiotherapy,” and “cancer,” among others. The literature was examined for the possible mechanism and preventive measures of sensorineural hearing loss induced by radiotherapy. Results We found that the incidence of RISNHL was closely related to the damage directly caused by ionizing radiation and the radiation-induced bystander effect. It also depends on the dose of radiation and the timing of chemotherapy. Studies confirmed that RISNHL is mainly involved in post-RT inflammatory response and changes in reactive oxygen species, mitogen-activated protein kinase, and p53 signaling pathways, leading to specific manners of cell death. We expect to reduce the incidence of hearing loss through advanced radiotherapy techniques, dose limitation of organs at risk, application of cell signaling inhibitors, use of antioxidants, induction of cochlear hair cell regeneration, and cochlear implantation. Conclusion RISNHL is associated with radiation damage to DNA, oxidative stress, and inflammation of cochlear cells, stria vascularis endothelial cells, vascular endothelial cells, spiral ganglion neurons, and other supporting cells. At present, the occurrence mechanism of RISNHL has not been clearly illustrated, and further studies are needed to better understand the underlying mechanism, which is crucial to promote the formulation of better strategies and prevent the occurrence of RISNHL.
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Rapamycin ameliorates age-related hearing loss in C57BL/6J mice by enhancing autophagy in the SGNs. Neurosci Lett 2022; 772:136493. [DOI: 10.1016/j.neulet.2022.136493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 01/25/2022] [Accepted: 01/25/2022] [Indexed: 01/15/2023]
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Geng Q, Li H, Zhang H, Lu M, Liu J, Wang F, Shen H, Yamoah EN, Jia Z, Lv P. Association between Ca v3 channel upregulation in spiral ganglion neurons and age-dependent hearing loss. Exp Gerontol 2021; 151:111429. [PMID: 34052348 DOI: 10.1016/j.exger.2021.111429] [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: 12/09/2020] [Revised: 05/09/2021] [Accepted: 05/26/2021] [Indexed: 01/12/2023]
Abstract
Cav3 channels play a critical role in maintaining calcium homeostasis, and its dysregulation is related to age-related diseases, such as age-related hearing loss (AHL). However, the underlying mechanism of the Cav3 channels involved in AHL remains unknown. Previous studies have shown that the degeneration of spiral ganglion neurons (SGNs) plays a critical role in AHL. Here, we explored the involvement of Cav3 channels in the dysregulation of SGNs in AHL. We used C57BL/6 mice as the AHL mouse model and found that the expression of Cav3 channels was increased in SGNs associated with age. The three subtypes of Cav3 channels were present in the apical, middle, and basal SGNs from young and older (AHL) mice. The immunostaining data suggest that Cav3.1 and Cav3.2 may contribute to Cav3 upregulation in SGNs of AHL mice. Additionally, we found that calpain-2 and apoptosis-inducing factor (AIF) were activated in SGNs from AHL mice. The inhibition of Cav3 channels or calpain-2 reduced AIF-activation in SGNs may affect neuronal survival. In conclusion, the findings suggest that Cav3 channels are upregulated in SGNs from AHL mice that may contribute to the degeneration of SGNs through the calpain-2-AIF apoptosis pathway in AHL mice.
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Affiliation(s)
- Qiaowei Geng
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, PR China; Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, Hebei Province 050017, PR China
| | - Hongchen Li
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, PR China; Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, Hebei Province 050017, PR China
| | - Haiwei Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, PR China; Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, Hebei Province 050017, PR China
| | - Mingshun Lu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, PR China; Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, Hebei Province 050017, PR China
| | - Jiaxi Liu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, PR China; Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, Hebei Province 050017, PR China
| | - Fei Wang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, PR China; Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, Hebei Province 050017, PR China
| | - Haitao Shen
- Lab of Pathology, Hebei Medical University, Shijiazhuang, Hebei 050017, PR China
| | - Ebenezer N Yamoah
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Reno, NV 89557, United States
| | - Zhanfeng Jia
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, PR China; Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, Hebei Province 050017, PR China
| | - Ping Lv
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei 050017, PR China; Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, Hebei Province 050017, PR China
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8
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Doostkam A, Mirkhani H, Iravani K, Karbalay-Doust S, Zarei K. Effect of Rutin on Diabetic Auditory Neuropathy in an Experimental Rat Model. Clin Exp Otorhinolaryngol 2020; 14:259-267. [PMID: 32764214 PMCID: PMC8373845 DOI: 10.21053/ceo.2019.02068] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/05/2020] [Indexed: 01/03/2023] Open
Abstract
Objectives Diabetic auditory neuropathy is a common complication of diabetes mellitus that has a major impact on patients’ quality of life. In this study, we assessed the efficacy of rutin in treating diabetic auditory neuropathy in an experimental rat model. Methods Forty Sprague-Dawley rats were randomly assigned to the following groups: group 1, control; group 2, diabetic rats; and groups 3–5, rats treated with rutin (at doses of 50, 100, and 150 mg/kg, respectively). We used auditory brain stem response, stereology of the spiral ganglion, and measurements of superoxide dismutase (SOD) and malondialdehyde (MDA) to evaluate the effects of treatment. Results Significant improvements in auditory neuropathy were observed in the rutin-treated groups in comparison with the diabetic group (P<0.05). Auditory threshold, wave latency, wave morphology, the volume and number of neurons in the spiral ganglion, and SOD and MDA activity showed improvements following treatment. Conclusion Rutin shows promise as a treatment modality for diabetic auditory neuropathy, but more trials are warranted for its clinical application.
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Affiliation(s)
- Aida Doostkam
- Department of Pharmacology, School of Medicine, Shiraz Nephro-Urology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hossein Mirkhani
- Department of Pharmacology, Medicinal and Natural Products Chemistry Research Center, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Kamyar Iravani
- Department of Otolaryngology, Otolaryngology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Saied Karbalay-Doust
- Department of Anatomy, Histomorphometry and Stereology Research Center, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Kazem Zarei
- Department of Otolaryngology, Otolaryngology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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Yu F, Xu X, Ren Z, Yang J, Kong F. Maternal high-decibel acoustic exposure elevates prenatal stress, impairing postnatal hearing thresholds associated with decreasing ribbon synapses in young rats. Reprod Toxicol 2019; 89:21-27. [PMID: 31238098 DOI: 10.1016/j.reprotox.2019.05.067] [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: 11/19/2018] [Revised: 05/16/2019] [Accepted: 05/30/2019] [Indexed: 10/26/2022]
Abstract
Maternal stress may affect the fetal auditory system than direct sound exposure. The objective of this study was to evaluate the role of prenatal stress due to high-decibel (dB) sound exposure on postnatal hearing and cochlear structure. Pregnant rats were exposed to 95 or 65 dB noise or music for 2 h once a day from gestational day 15 until delivery. The serum corticosterone was measured in the pregnant dams and pups. On postnatal day 22, pups underwent auditory brainstem response (ABR) testing. Then, the cochleae were immediately harvested for biochemical and molecular investigations. Prenatal stress impaired reproductive parameters, increased serum corticosterone and ABR thresholds with the decrease in wave I peak amplitude and the number of pre-synaptic ribbon. Thus, prenatal stress induces postnatal hearing loss in young rats, which are related to the reduction of ribbon synapses.
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Affiliation(s)
- Fei Yu
- School of Public Health, He University, No.66 Sishui Street, Hunnan New District, Shenyang, 110163, China.
| | - Xueying Xu
- School of Public Health, He University, No.66 Sishui Street, Hunnan New District, Shenyang, 110163, China
| | - Zhongjuan Ren
- School of Public Health, He University, No.66 Sishui Street, Hunnan New District, Shenyang, 110163, China
| | - Jun Yang
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, China
| | - Fanxue Kong
- Department of Orthopaedics, First Affiliated Hospital of Dalian Medical University, No.222 Zhongshan Road, Xigang District, Dalian, China.
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Shen H, Liu W, Geng Q, Li H, Lu M, Liang P, Zhang B, Yamoah EN, Lv P. Age-Dependent Up-Regulation of HCN Channels in Spiral Ganglion Neurons Coincide With Hearing Loss in Mice. Front Aging Neurosci 2018; 10:353. [PMID: 30459593 PMCID: PMC6232381 DOI: 10.3389/fnagi.2018.00353] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 10/17/2018] [Indexed: 01/05/2023] Open
Abstract
Age-related hearing loss (AHL) is the most common sensory disorder in the elderly population, and the etiologies are diverse. To understand the underlying mechanisms of AHL, one strategy is to identify correlates of the disease for comprehensive evaluation of treatment approaches. Dysfunction and degeneration of spiral ganglion neurons (SGNs) are major contributors to AHL. Previously, we showed that one of the changes in the aging auditory system is SGN excitability increase in mice. Since hyperpolarization-activated cyclic nucleotide-gated (HCN) channels play important roles in determining neuronal excitability, we predicted that HCN channels in SGNs are involved in AHL. To investigate the contribution of HCN channels to AHL, we examined the expression and biophysical properties of HCN channels in SGNs from adult (2–3 months) and 11–12-month-old mice. We report a dramatic increase of HCN channel current (Ih) in SGNs in old mice (11–12 months old). The results matched well with increased expression of HCN1 and HCN2 subunits, suggesting that upregulation of HCN channels in SGNs is one of the important facets of the aging SGNs. Moreover, the activity of Ih produced a major impact on the firing properties of SGNs in older mice. The upregulation of Ih may contribute to AHL by regulating SGN excitability. We assessed whether increased SGNs excitability dovetail with neurodegeneration. Apoptosis-inducing factor (AIF)-mediated apoptosis in SGNs was observed in old mice and activation of HCN channels mediates AIF activation. Thus, these findings demonstrate stark correlation between age-dependent increased expression of HCN channels and Ih, and apoptosis in SGNs, which may contribute towards the varied mechanisms of AHL.
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Affiliation(s)
- Haitao Shen
- Laboratory of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Weilin Liu
- Division of Cardiovascular Medicine, Hebei Province Geriatric Hospital, Shijiazhuang, China
| | - Qiaowei Geng
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Hongchen Li
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Mingshun Lu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Peng Liang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Bo Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Ebenezer N Yamoah
- Department of Physiology, School of Medicine, University of Nevada, Reno, NV, United States
| | - Ping Lv
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
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Central Compensation in Auditory Brainstem after Damaging Noise Exposure. eNeuro 2018; 5:eN-CFN-0250-18. [PMID: 30123822 PMCID: PMC6096756 DOI: 10.1523/eneuro.0250-18.2018] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 07/19/2018] [Indexed: 12/15/2022] Open
Abstract
Noise exposure is one of the most common causes of hearing loss and peripheral damage to the auditory system. A growing literature suggests that the auditory system can compensate for peripheral loss through increased central neural activity. The current study sought to investigate the link between noise exposure, increases in central gain, synaptic reorganization, and auditory function. All axons of the auditory nerve project to the cochlear nucleus, making it a requisite nucleus for sound detection. As the first synapse in the central auditory system, the cochlear nucleus is well positioned to respond plastically to loss of peripheral input. To investigate noise-induced compensation in the central auditory system, we measured auditory brainstem responses (ABRs) and auditory perception and collected tissue from mice exposed to broadband noise. Noise-exposed mice showed elevated ABR thresholds, reduced ABR wave 1 amplitudes, and spiral ganglion neuron loss. Despite peripheral damage, noise-exposed mice were hyperreactive to loud sounds and showed nearly normal behavioral sound detection thresholds. Ratios of late ABR peaks (2–4) relative to the first ABR peak indicated that brainstem pathways were hyperactive in noise-exposed mice, while anatomical analysis indicated there was an imbalance between expression of excitatory and inhibitory proteins in the ventral cochlear nucleus. The results of the current study suggest that a reorganization of excitation and inhibition in the ventral cochlear nucleus may drive hyperactivity in the central auditory system. This increase in central gain can compensate for peripheral loss to restore some aspects of auditory function.
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12
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Contralateral Suppression of DPOAEs in Mice after Ouabain Treatment. Neural Plast 2018; 2018:6890613. [PMID: 29849563 PMCID: PMC5914095 DOI: 10.1155/2018/6890613] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/25/2018] [Accepted: 02/27/2018] [Indexed: 12/26/2022] Open
Abstract
Medial olivocochlear (MOC) efferent feedback is suggested to protect the ear from acoustic injury and to increase its ability to discriminate sounds against a noisy background. We investigated whether type II spiral ganglion neurons participate in the contralateral suppression of the MOC reflex. The application of ouabain to the round window of the mouse cochlea selectively induced the apoptosis of the type I spiral ganglion neurons, left the peripherin-immunopositive type II spiral ganglion neurons intact, and did not affect outer hairs, as evidenced by the maintenance of the distorted product otoacoustic emissions (DPOAEs). With the ouabain treatment, the threshold of the auditory brainstem response increased significantly and the amplitude of wave I decreased significantly in the ouabain-treated ears, consistent with the loss of type I neurons. Contralateral suppression was measured as reduction in the amplitude of the 2f1−f2 DPOAEs when noise was presented to the opposite ear. Despite the loss of all the type I spiral ganglion neurons, virtually, the amplitude of the contralateral suppression was not significantly different from the control when the suppressor noise was delivered to the treated cochlea. These results are consistent with the type II spiral ganglion neurons providing the sensory input driving contralateral suppression of the MOC reflex.
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Jang S, Cho HH, Kim SH, Lee KH, Cho YB, Park JS, Jeong HS. Transplantation of human adipose tissue-derived stem cells for repair of injured spiral ganglion neurons in deaf guinea pigs. Neural Regen Res 2016; 11:994-1000. [PMID: 27482231 PMCID: PMC4962600 DOI: 10.4103/1673-5374.184503] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2015] [Indexed: 12/30/2022] Open
Abstract
Excessive noise, ototoxic drugs, infections, autoimmune diseases, and aging can cause loss of spiral ganglion neurons, leading to permanent sensorineural hearing loss in mammals. Stem cells have been confirmed to be able to differentiate into spiral ganglion neurons. Little has been reported on adipose tissue-derived stem cells (ADSCs) for repair of injured spiral ganglion neurons. In this study, we hypothesized that transplantation of neural induced-human ADSCs (NI-hADSCs) can repair the injured spiral ganglion neurons in guinea pigs with neomycin-induced sensorineural hearing loss. NI-hADSCs were induced with culture medium containing basic fibroblast growth factor and forskolin and then injected to the injured cochleae. Guinea pigs that received injection of Hanks' balanced salt solution into the cochleae were used as controls. Hematoxylin-eosin staining showed that at 8 weeks after cell transplantation, the number of surviving spiral ganglion neurons in the cell transplantation group was significantly increased than that in the control group. Also at 8 weeks after cell transplantation, immunohistochemical staining showed that a greater number of NI-hADSCs in the spiral ganglions were detected in the cell transplantation group than in the control group, and these NI-hADSCs expressed neuronal markers neurofilament protein and microtubule-associated protein 2. Within 8 weeks after cell transplantation, the guinea pigs in the cell transplantation group had a gradually decreased auditory brainstem response threshold, while those in the control group had almost no response to 80 dB of clicks or pure tone burst. These findings suggest that a large amount of NI-hADSCs migrated to the spiral ganglions, survived for a period of time, repaired the injured spiral ganglion cells, and thereby contributed to the recovery of sensorineural hearing loss in guinea pigs.
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Affiliation(s)
- Sujeong Jang
- Department of Physiology, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Hyong-Ho Cho
- Department of Otolaryngology, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Song-Hee Kim
- Department of Physiology, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Kyung-Hwa Lee
- Department of Pathology, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Yong-Bum Cho
- Department of Otolaryngology, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Jong-Seong Park
- Department of Physiology, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Han-Seong Jeong
- Department of Physiology, Chonnam National University Medical School, Gwangju, Republic of Korea
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14
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Golub VM, Brewer J, Wu X, Kuruba R, Short J, Manchi M, Swonke M, Younus I, Reddy DS. Neurostereology protocol for unbiased quantification of neuronal injury and neurodegeneration. Front Aging Neurosci 2015; 7:196. [PMID: 26582988 PMCID: PMC4628120 DOI: 10.3389/fnagi.2015.00196] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 10/02/2015] [Indexed: 01/31/2023] Open
Abstract
Neuronal injury and neurodegeneration are the hallmark pathologies in a variety of neurological conditions such as epilepsy, stroke, traumatic brain injury, Parkinson's disease and Alzheimer's disease. Quantification of absolute neuron and interneuron counts in various brain regions is essential to understand the impact of neurological insults or neurodegenerative disease progression in animal models. However, conventional qualitative scoring-based protocols are superficial and less reliable for use in studies of neuroprotection evaluations. Here, we describe an optimized stereology protocol for quantification of neuronal injury and neurodegeneration by unbiased counting of neurons and interneurons. Every 20th section in each series of 20 sections was processed for NeuN(+) total neuron and parvalbumin(+) interneuron immunostaining. The sections that contain the hippocampus were then delineated into five reliably predefined subregions. Each region was separately analyzed with a microscope driven by the stereology software. Regional tissue volume was determined by using the Cavalieri estimator, as well as cell density and cell number were determined by using the optical disector and optical fractionator. This protocol yielded an estimate of 1.5 million total neurons and 0.05 million PV(+) interneurons within the rat hippocampus. The protocol has greater predictive power for absolute counts as it is based on 3D features rather than 2D images. The total neuron counts were consistent with literature values from sophisticated systems, which are more expensive than our stereology system. This unbiased stereology protocol allows for sensitive, medium-throughput counting of total neurons in any brain region, and thus provides a quantitative tool for studies of neuronal injury and neurodegeneration in a variety of acute brain injury and chronic neurological models.
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Affiliation(s)
- Victoria M. Golub
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Jonathan Brewer
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Xin Wu
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Ramkumar Kuruba
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Jenessa Short
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Maunica Manchi
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Megan Swonke
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Iyan Younus
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
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15
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Wong ACY, Ryan AF. Mechanisms of sensorineural cell damage, death and survival in the cochlea. Front Aging Neurosci 2015; 7:58. [PMID: 25954196 PMCID: PMC4404918 DOI: 10.3389/fnagi.2015.00058] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/05/2015] [Indexed: 12/20/2022] Open
Abstract
The majority of acquired hearing loss, including presbycusis, is caused by irreversible damage to the sensorineural tissues of the cochlea. This article reviews the intracellular mechanisms that contribute to sensorineural damage in the cochlea, as well as the survival signaling pathways that can provide endogenous protection and tissue rescue. These data have primarily been generated in hearing loss not directly related to age. However, there is evidence that similar mechanisms operate in presbycusis. Moreover, accumulation of damage from other causes can contribute to age-related hearing loss (ARHL). Potential therapeutic interventions to balance opposing but interconnected cell damage and survival pathways, such as antioxidants, anti-apoptotics, and pro-inflammatory cytokine inhibitors, are also discussed.
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Affiliation(s)
- Ann C Y Wong
- Department of Surgery/Division of Otolaryngology, University of California, San Diego School of Medicine La Jolla, CA, USA ; Department of Physiology and Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales Sydney, NSW, Australia
| | - Allen F Ryan
- Department of Surgery/Division of Otolaryngology, University of California, San Diego School of Medicine La Jolla, CA, USA ; Veterans Administration Medical Center La Jolla, CA, USA ; Department of Neurosciences, University of California, San Diego School of Medicine La Jolla, CA, USA
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16
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McGuire B, Fiorillo B, Ryugo DK, Lauer AM. Auditory nerve synapses persist in ventral cochlear nucleus long after loss of acoustic input in mice with early-onset progressive hearing loss. Brain Res 2015; 1605:22-30. [PMID: 25686750 DOI: 10.1016/j.brainres.2015.02.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/23/2015] [Accepted: 02/06/2015] [Indexed: 01/09/2023]
Abstract
Perceptual performance in persons with hearing loss, especially those using devices to restore hearing, is not fully predicted by traditional audiometric measurements designed to evaluate the status of peripheral function. The integrity of auditory brainstem synapses may vary with different forms of hearing loss, and differential effects on the auditory nerve-brain interface may have particularly profound consequences for the transfer of sound from ear to brain. Loss of auditory nerve synapses in ventral cochlear nucleus (VCN) has been reported after acoustic trauma, ablation of the organ of Corti, and administration of ototoxic compounds. The effects of gradually acquired forms deafness on these synapses are less well understood. We investigated VCN gross morphology and auditory nerve synapse integrity in DBA/2J mice with early-onset progressive sensorineural hearing loss. Hearing status was confirmed using auditory brainstem response audiometry and acoustic startle responses. We found no change in VCN volume, number of macroneurons, or number of VGLUT1-positive auditory nerve terminals between young adult and older, deaf DBA/2J. Cell-type specific analysis revealed no difference in the number of VGLUT1 puncta contacting bushy and multipolar cell body profiles, but the terminals were smaller in deaf DBA/2J mice. Transmission electron microscopy confirmed the presence of numerous healthy, vesicle-filled auditory nerve synapses in older, deaf DBA/2J mice. The present results suggest that synapses can be preserved over a relatively long time-course in gradually acquired deafness. Elucidating the mechanisms supporting survival of central auditory nerve synapses in models of acquired deafness may reveal new opportunities for therapeutic intervention.
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Affiliation(s)
- Brian McGuire
- Center for Hearing and Balance and Department of Otolaryngology-HNS, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Benjamin Fiorillo
- Center for Hearing and Balance and Department of Otolaryngology-HNS, Johns Hopkins University, Baltimore, MD 21205, USA
| | - David K Ryugo
- Hearing Research Unit, Garvan Institute of Medical Research, Darlinghurst 2010, NSW, Australia; School of Medical Sciences, University of New South Wales, Kensington 2052, NSW, Australia
| | - Amanda M Lauer
- Center for Hearing and Balance and Department of Otolaryngology-HNS, Johns Hopkins University, Baltimore, MD 21205, USA.
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