title: Type IX collagen knock-out mouse shows progressive hearing loss.
abstract: Type IX collagen is one of the important components, together with type II, V, and XI collagens, in the tectorial membrane of the organ of Corti. To confirm the significance of type IX collagen for normal hearing, we assessed the detailed morphological and electrophysiological features of type IX collagen knock-out mice, which have recently been reported as a deafness model. Through assessment by auditory brainstem response (ABR), knock-out mice were shown to have progressive hearing loss. At the light microscopic level, the tectorial membrane of knock-out mice was found to be abnormal in shape. These morphological changes started in the basal turn and were progressive toward the apical turn. Electron microscopy confirmed disturbance of organization of the collagen fibrils. These results suggest that mutations in type IX collagen genes may lead to abnormal integrity of collagen fibers in the tectorial membrane.
authors.affiliation: Department of Otorhinolaryngology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan.
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Suzuki
authors.forename: Kenji
authors.initials: K
authors.lastname: Asamura
authors.forename: Yasutake
authors.initials: Y
authors.lastname: Kikuchi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takumi
authors.forename: Satoko
authors.initials: S
authors.lastname: Abe
authors.forename: Yasutada
authors.initials: Y
authors.lastname: Imamura
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Hayashi
authors.forename: Attila
authors.initials: A
authors.lastname: Aszodi
authors.forename: Reinhard
authors.initials: R
authors.lastname: Fässler
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Usami
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology; D001933:Brain Stem / Q000503:physiopathology; D024081:Collagen Type IX / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D018450:Disease Progression; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D034381:Hearing Loss / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout / Q000502:physiology*; D046529:Microscopy, Electron, Transmission / Q000379:methods; D013680:Tectorial Membrane / Q000473:pathology / Q000648:ultrastructure; D013997:Time Factors
chemical_list: D024081:Collagen Type IX