GFAP aggregates in the cochlear nerve increase the noise vulnerability of sensory cells in the organ of Corti in the murine model of Alexander disease

2008 ◽  
Vol 62 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Masatsugu Masuda ◽  
Kenji F. Tanaka ◽  
Sho Kanzaki ◽  
Kenichiro Wakabayashi ◽  
Naoki Oishi ◽  
...  
Keyword(s):  
Murine Model ◽  
Organ Of Corti ◽  
Cochlear Nerve ◽  
Alexander Disease ◽  
Sensory Cells

scholarly journals THE ULTRASTRUCTURE OF THE SENSORY HAIRS AND ASSOCIATED ORGANELLES OF THE COCHLEAR INNER HAIR CELL, WITH REFERENCE TO DIRECTIONAL SENSITIVITY

1966 ◽  
Vol 29 (3) ◽  
pp. 497-505 ◽  
Author(s):  
Arndt J. Duvall ◽  
Åke Flock ◽  
Jan Wersäll
Keyword(s):  
Guinea Pig ◽  
Hair Cell ◽  
Basal Body ◽  
Organ Of Corti ◽  
Sensory Cells ◽  
Directional Sensitivity ◽  
Inner Hair Cell ◽  
Lateral Line Organ ◽  
Sensory Hairs ◽  
Line Organ

From the apical end of the inner hair cell of the organ of Corti in the guinea pig cochlea protrude four to five rows of stereocilia shaped in a pattern not unlike the wings of a bird. In the area devoid of cuticular substance facing toward the tunnel of Corti lies a consistently present centriole. The ultrastructure of this centriole is similar to that of the basal body of the kinocilium located in the periphery of the sensory hair bundles in the vestibular and lateral line organ sensory cells and to that of the centrioles of other cells. The physiological implications of the anatomical orientation of this centriole are discussed in terms of directional sensitivity.

scholarly journals Metabolic Enzyme Alterations and Astrocyte Dysfunction in a Murine Model of Alexander Disease with Severe Reactive Gliosis

2021 ◽  
pp. 100180
Author(s):  
Michael R. Heaven ◽  
Anthony W. Herren ◽  
Daniel L. Flint ◽  
Natasha L. Pacheco ◽  
Jiangtao Li ◽  
...  
Keyword(s):  
Murine Model ◽  
Alexander Disease ◽  
Reactive Gliosis ◽  
Metabolic Enzyme

Involvement of TNF-α and IFN-γ in Inflammation-Mediated Cochlear Injury

2019 ◽  
Vol 128 (6_suppl) ◽  
pp. 8S-15S ◽  
Author(s):  
Sung K. Moon ◽  
Jeong-Im Woo ◽  
David J. Lim
Keyword(s):  
Cell Injury ◽  
Ex Vivo ◽  
Organ Of Corti ◽  
Blue Staining ◽  
Sensory Cells ◽  
Spiral Ligament ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Ifn Γ ◽  
High Concentrations

Objectives: Inflammation is crucial for the pathogenesis of acquired sensorineural hearing loss, but the precise mechanism involved remains elusive. Among a number of inflammatory mediators, tumor necrosis factor-alpha (TNF-α) plays a pivotal role in cisplatin ototoxicity. However, TNF-α alone is cytotoxic to cochlear sensory cells only at the extremely high concentrations, suggesting the involvement of other factors that may sensitize cells to TNF-α cytotoxicity. Since interferon gamma (IFN-γ) importantly contributes to the cochlear inflammatory processes, we aim to determine whether and how IFN-γ affects TNF-α cytotoxicity to cochlear sensory cells. Methods: TNF-α expression was determined with western blotting in RSL cells and immunolabeling of mouse temporal bone sections. HEI-OC1 cell viability was determined with MTT assays, cytotoxicity assays, and cytometric analysis with methylene blue staining. Cochlear sensory cell injury was determined in the organotypic culture of the mouse organ of Corti. Results: Spiral ligament fibrocytes were shown to upregulate TNF-α in response to pro-inflammatory stimulants. We demonstrated IFN-γ increases the susceptibility of HEI-OC1 cells to TNF-α cytotoxicity via JAK1/2-STAT1 signaling. TNFR1-mediated Caspase-1 activation was found to mediate the sensitization effect of IFN-γ on TNF-α cytotoxicity. The combination of IFN-γ and TNF-α appeared to augment cisplatin cytotoxicity to cochlear sensory cells ex vivo. Conclusions: Taken together, these findings suggest the involvement of IFN-γ in the sensitization of cochlear cells to TNF-α cytotoxicity, which would enable us to better understand the complex mechanisms underlying inflammation-mediated cochlear injury.

scholarly journals Non-sensory cells in the deafened organ of Corti: approaches for repair

2007 ◽  
Vol 51 (6-7) ◽  
pp. 649-654 ◽  
Author(s):  
Yehoash Raphael ◽  
Young-Ho Kim ◽  
Yasunori Osumi ◽  
Masahiko Izumikawa
Keyword(s):  
Organ Of Corti ◽  
Sensory Cells

scholarly journals Selective Removal of Lateral Olivocochlear Efferents Increases Vulnerability to Acute Acoustic Injury

2007 ◽  
Vol 97 (2) ◽  
pp. 1775-1785 ◽  
Author(s):  
Keith N. Darrow ◽  
Stéphane F. Maison ◽  
M. Charles Liberman
Keyword(s):  
Brain Stem ◽  
Otoacoustic Emissions ◽  
Outer Hair Cells ◽  
Cochlear Nerve ◽  
Sensory Cells ◽  
Neural Responses ◽  
Distortion Product ◽  
Auditory Brain Stem ◽  
Pharmacological Studies

Cochlear sensory cells and neurons receive efferent feedback from the olivocochlear (OC) system. The myelinated medial component of the OC system and its effects on outer hair cells (OHCs) have been implicated in protection from acoustic injury. The unmyelinated lateral (L)OC fibers target ipsilateral cochlear nerve dendrites and pharmacological studies suggest the LOC's dopaminergic component may protect these dendrites from excitotoxic effects of acoustic overexposure. Here, we explore LOC function in vivo by selective stereotaxic destruction of LOC cell bodies in mouse. Lesion success in removing the LOC, and sparing the medial (M)OC, was assessed by histological analysis of brain stem sections and cochlear whole mounts. Auditory brain stem responses (ABRs), a neural-based metric, and distortion product otoacoustic emissions (DPOAEs), an OHC-based metric, were measured in control and surgical mice. In cases where the LOC was at least partially destroyed, there were increases in suprathreshold neural responses that were frequency- and level-independent and not attributable to OHC-based effects. These interaural response asymmetries were not found in controls or in cases where the lesion missed the LOC. In LOC-lesion cases, after exposure to a traumatic stimulus, temporary threshold shifts were greater in the ipsilateral ear, but only when measured in the neural response; OHC-based measurements were always bilaterally symmetric, suggesting OHC vulnerability was unaffected. Interaural asymmetries in threshold shift were not found in either unlesioned controls or in cases that missed the LOC. These findings suggest that the LOC modulates cochlear nerve excitability and protects the cochlea from neural damage in acute acoustic injury.

Murine model of Alexander disease: Analysis of GFAP aggregate formation and its pathological significance

Glia ◽  
2007 ◽  
Vol 55 (6) ◽  
pp. 617-631 ◽  
Author(s):  
Kenji F. Tanaka ◽  
Hirohide Takebayashi ◽  
Yoshihiko Yamazaki ◽  
Katsuhiko Ono ◽  
Masae Naruse ◽  
...  
Keyword(s):  
Murine Model ◽  
Alexander Disease ◽  
Aggregate Formation ◽  
Disease Analysis

scholarly journals Two Photon Fluorescence Microscopy of the Unstained Human Cochlea Reveals Organ of Corti Cytoarchitecture

2021 ◽  
Vol 15 ◽  
Author(s):  
Janani S. Iyer ◽  
Richard Seist ◽  
In Seok Moon ◽  
Konstantina M. Stankovic
Keyword(s):  
Fluorescence Microscopy ◽  
Auditory Nerve ◽  
Imaging Technique ◽  
Organ Of Corti ◽  
Nerve Fibers ◽  
Sensory Cells ◽  
Two Photon ◽  
Human Cochlea ◽  
Two Photon Fluorescence ◽  
Photon Fluorescence

Sensorineural hearing loss (SNHL) is the most common sensory deficit worldwide, and it typically originates from the cochlea. Methods to visualize intracochlear cells in living people are currently lacking, limiting not only diagnostics but also therapies for SNHL. Two-photon fluorescence microscopy (TPFM) is a high-resolution optical imaging technique. Here we demonstrate that TPFM enables visualization of sensory cells and auditory nerve fibers in an unstained, non-decalcified adult human cochlea.

Outer Hair Cells Provide Active Tuning in the Organ of Corti

Physiology ◽  
1998 ◽  
Vol 13 (3) ◽  
pp. 107-111 ◽  
Author(s):  
Mats Ulfendahl ◽  
Åke Flock
Keyword(s):  
Mechanical Behavior ◽  
Hair Cells ◽  
Organ Of Corti ◽  
High Sensitivity ◽  
Outer Hair Cells ◽  
Sensory Cells ◽  
Effector Cells ◽  
Hearing Organ

The detection of sound by the mammalian hearing organ, the organ of Corti, is far from a passive process with the sensory cells acting as mere receptors. The high sensitivity and sharp tuning of the auditory apparatus are very much dependant on the active mechanical behavior of the outer hair cells, acting as effector cells.

An evaluation of the use of scanning and transmission electronmicroscopy in a study of the gentamicin-damaged guinea-pig organ of Corti

1979 ◽  
Vol 93 (1) ◽  
pp. 7-23 ◽  
Author(s):  
E. S. Harpur ◽  
J. B. Bridges
Keyword(s):  
Guinea Pig ◽  
Organ Of Corti ◽  
Cell Loss ◽  
Sensory Cells ◽  
Pathological Changes ◽  
Transmission Electron ◽  
Scanning Electronmicroscopy ◽  
Suitable Technique ◽  
Transmission Electronmicroscopy ◽  
Surface Changes

AbstractScanning electronmicroscopy and transmission electronmicroscopy were used to study the normal and gentamicin-damaged guinea-pig organ of Corti. Scanning electronmicroscopy was principally used to locate the lesion and quantify the cell loss but also permitted a detailed study to be made of the degenerative surface changes. However, since consistent surface changes are not seen until intracellular degeneration has progressed to a great extent, scanning electronmicroscopy is not a suitable technique for identifying early degenerative changes in the sensory cells of the organ of Corti. Consequently, before conclusions may be drawn about the absence of pathological changes in the neuro-epithelium it also should be examined using transmission electron-microscopy.

scholarly journals Scanning Electron Microscopy of the Human Organ of Corti

1983 ◽  
Vol 76 (4) ◽  
pp. 269-278 ◽  
Author(s):  
A Wright
Keyword(s):  
Hair Cells ◽  
Organ Of Corti ◽  
Outer Hair Cells ◽  
Sensory Cells ◽  
Surface Appearance ◽  
Human Organ ◽  
Human Cochlea ◽  
Temporal Bones ◽  
Subsequent Staining ◽  
Scanning Electron

The human cochlea has been preserved from post-mortem autolysis by perfusion with a fixative shortly after death. Subsequent staining with osmium permits dissection of this structure from the temporal bone. (Temporal bones were obtained from eight patients). When prepared for examination in the scanning electron microscope, the auditory sensory cells are found to be located in the band-like organ of Corti which extends the length of the cochlea. The sensory cells have a cluster of stereocilia projecting from their free upper surface and because of this are called hair cells. The hair cells are divided into two separate groups: a single row of inner hair cells, which show little variation in their surface appearance along the length of the cochlea, and three or four rows of outer hair cells whose cilia change in conformation and increase in length along the cochlea.

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