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Zhao Z, Yao W, Wang M, Wang J, Zhang T. Radial Flow Field of Spiral Cochlea and Its Effect On Stereocilia. J Biomech Eng 2022; 144:1143034. [PMID: 35789250 DOI: 10.1115/1.4054930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Indexed: 11/08/2022]
Abstract
The opening of the ion channels ultimately depends on the movement and energy conversion of the microstructural organization. It has not been clear how active sound amplification is generated by the microstructure of the cochlea's characteristic spiral shape. In this paper, an analytical model of the spiral cochlea is developed to investigate the radial flow field generated by the spiral shape of the cochlea and its effect on the outer hair cell stereocilia, and to analyze the effect of the spiral shape on the micromechanics of the cochlea. The results show that the spiral shape of the cochlea exerts a radial shear force on the hair cell stereocilia by generating a radial flow field. This causes the stereocilia to deflect in the radial flow field, with the maximum deflection occurring at the apex of the cochlea. This finding explains the microscopic mechanism that causes the cochlea's spiral shape to enhance low-frequency hearing in humans, and it provides a basis for further studies on the contribution of the movement of stereocilia in the radial flow field of the lymphatic fluid to activate ion channels for auditory production.
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Affiliation(s)
- Zhengshan Zhao
- School of Mechanics and Engineering Science, Shanghai University, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai, 200072, PRC
| | - Wenjuan Yao
- School of Mechanics and Engineering Science, Shanghai University, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai, 200072, PRC
| | - Mianzhi Wang
- School of Mechanics and Engineering Science, Shanghai University, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai, 200072, PRC
| | - Jiakun Wang
- School of Mechanics and Engineering Science, Shanghai University, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai, 200072, PRC
| | - Tianyu Zhang
- ENT Institute, Eye & ENT Hospital of Fudan University, Hearing Medicine Key Laboratory, National Health Commission of China; Department of Facial Plastic Reconstruction Surgery, Eye & ENT Hospital of Fudan University, Shanghai 200031, PRC
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Wang SQ, Li CL, Xu JQ, Chen LL, Xie YZ, Dai PD, Ren LJ, Yao WJ, Zhang TY. The Effect of Endolymphatic Hydrops and Mannitol Dehydration Treatment on Guinea Pigs. Front Cell Neurosci 2022; 16:836093. [PMID: 35480960 PMCID: PMC9035551 DOI: 10.3389/fncel.2022.836093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/24/2022] [Indexed: 01/14/2023] Open
Abstract
Background Endolymphatic hydrops (EH) is considered as the pathological correlate of Menière’s disease (MD) and cause of hearing loss. The mechanism of EH, remaining unrevealed, poses challenges for formalized clinical trials. Objective This study aims to investigate the development of hearing loss, as well as the effect of dehydration treatment on EH animal models. Methods In this study, different severity EH animal models were created. The laser Doppler vibrometer (LDV) and auditory brainstem responses (ABR) were used to study the effects of EH and the dehydration effects of mannitol. The LDV was used to measure the vibration of the round window membrane (RWM) reflecting the changes in inner ear impedance. ABR was used to evaluate the hearing changes. Furthermore, tissue section and scanning electron microscopy (SEM) observations were used to analyze the anatomical change to the cochlea and outer hair cells. Results The RWM vibrations decreased with the severity of EH, indicating an increase in the cochlear impedance. The dehydration therapy lowered the impedance to restore acoustic transduction in EH 10- and 20-day animal models. Simultaneously, the ABR thresholds increased in EH models and were restored after dehydration. Moreover, a difference in the hearing was found between ABR and LDV results in severe EH animal models, and the dehydration therapy was less effective, indicating a sensorineural hearing loss (SNHL). Conclusion Endolymphatic hydrops causes hearing loss by increasing the cochlear impedance in all tested groups, and mannitol dehydration is an effective therapy to restore hearing. However, SNHL occurs for the EH 30-day animal models, limiting the effectiveness of dehydration. Our results suggest the use of dehydrating agents in the early stage of EH.
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Affiliation(s)
- Shu-Qi Wang
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Chen-Long Li
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
- Hearing Medicine Key Laboratory, National Health Commission of China, Shanghai, China
| | - Jing-Qi Xu
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Li-Li Chen
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
- Hearing Medicine Key Laboratory, National Health Commission of China, Shanghai, China
| | - You-Zhou Xie
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
- Hearing Medicine Key Laboratory, National Health Commission of China, Shanghai, China
| | - Pei-Dong Dai
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Liu-Jie Ren
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
- Hearing Medicine Key Laboratory, National Health Commission of China, Shanghai, China
- *Correspondence: Liu-Jie Ren,
| | - Wen-Juan Yao
- School of Mechanics and Engineering Science, Shanghai University, Shanghai, China
- Shanghai Institute of Applied Mathematics and Mechanics, Shanghai, China
- Wen-Juan Yao,
| | - Tian-Yu Zhang
- Department of Facial Plastic Reconstruction Surgery, Eye and ENT Hospital of Fudan University, Shanghai, China
- ENT Institute, Eye and ENT Hospital of Fudan University, Shanghai, China
- Hearing Medicine Key Laboratory, National Health Commission of China, Shanghai, China
- Tian-Yu Zhang,
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Masalski M, Wąż A, Błauciak P, Zatoński T, Morawski K. Handheld laser-fiber vibrometry probe for assessing auditory ossicles displacement. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210077RR. [PMID: 34291616 PMCID: PMC8292735 DOI: 10.1117/1.jbo.26.7.077001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE Measurements of auditory ossicles displacement are commonly carried out by means of laser-Doppler vibrometry (LDV), which is considered to be a gold standard. The limitation of the LDV method, especially for in vivo measurements, is the necessity to expose an object in a straight line to a laser beam operating from a distance. An alternative to this approach is the use of a handheld laser-fiber vibrometry probe (HLFVP) with a curved tip. AIM We evaluate the feasibility of an HLFVP with a curved tip for measuring sound-induced displacement of the auditory ossicles. APPROACH A handheld vibrometer probe guiding the laser beam with a fiber-optic cable was used for displacement measurements of the incus body and the posterior crus of the stapes. Tonal stimuli at frequencies of 0.5, 1, 2, and 4 kHz were presented by means of an insert earphone positioned in the outer ear canal. The probe was fixed at the measurement site using a tripod or hand-held by one of the two surgeons. RESULTS The measurements were carried out on six fresh temporal bones. Multivariate analysis of variance showed statistically significant differences for stimulus frequency (F3,143 = 29.37, p < 0.001, and η2 = 0.35), bone (F5,143 = 4.61, p = 0.001, and η2 = 0.01), and measurement site (F1,143 = 4.74, p = 0.03, and η2 = 0.02) in the absence of statistically significant differences for the probe fixation method (F2,143 = 0.15, p = 0.862, and η2 = 0.001). Standard deviations of the means were 6.9, 2.6, 1.9, and 0.6 nm / Pa for frequency, bone, site, and fixation, respectively. Ear transfer functions were found to be consistent with literature data. CONCLUSIONS The feasibility of applying HLFVP to measure the displacement of auditory ossicles has been confirmed. HLFVP offers the possibility of carrying out measurements at various angles; however, this needs to be standardized taking into account anatomical limitations and surgical convenience.
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Affiliation(s)
- Marcin Masalski
- Wroclaw Medical University, Department of Otolaryngology Head and Neck Surgery, Wroclaw, Poland
- Wroclaw University of Science and Technology, Department of Biomedical Engineering, Wroclaw, Poland
| | - Adam Wąż
- Wroclaw University of Science and Technology, Department of Field Theory, Electronic Circuits, and Optoelectronics, Wroclaw, Poland
| | | | - Tomasz Zatoński
- Wroclaw Medical University, Department of Otolaryngology Head and Neck Surgery, Wroclaw, Poland
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