Progressive Degeneration of Stereocilia in Cochlear Hair Cells in Hearing-impaired Kuru2 Mice

• Published in: In vivo (Athens) Vol. 19; no. 4; pp. 675 - 681
• Main Authors: Watanabe, Michiko, Akiyama, Nobutake, Hasegawa, Noriko, Manome, Yoshinobu
• Format: Journal Article
• Language: English
• Published: Greece International Institute of Anticancer Research 01-07-2005
• Subjects: Animals; Animals, Newborn; Cilia - pathology; Cilia - ultrastructure; Crosses, Genetic; Female; Hair Cells, Auditory, Inner - pathology; Hair Cells, Auditory, Inner - ultrastructure; Hair Cells, Vestibular - pathology; Hair Cells, Vestibular - ultrastructure; Hearing Loss - genetics; Hearing Loss - pathology; Hearing Loss - physiopathology; Male; Mice; Mice, Inbred ICR; Mice, Mutant Strains; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Spiral Ganglion - pathology; Spiral Ganglion - ultrastructure
• ISSN: 0258-851X; 1791-7549

Background: We previously isolated a mouse strain, kuru 2 , which exhibits abnormal behavior and hearing impairment. To investigate the etiology of this impairment, the ultrastructure
of the inner ear was examined. Materials and Methods: The morphologies of the cochlea and the vestibule of control (Jcl:ICR)
and mutant mice were analyzed by electron microscopy. In some experiments, the mice were cross-mated and their offspring examined.
Results: The mutant mice displayed progressive degeneration of the stereocilia in the cochlea. The stereocilia started to
degenerate on post-natal day 10 and, subsequently, the hair bundles continued to degenerate. On day 18, degeneration of the
stereocilia was complete. In contrast, the vestibule was intact. Discussion: Many mutant mice display hearing impairment.
These mice demonstrate a characteristic morphology of the inner ear and, since correlations may be made with corresponding
human diseases, the current results could contribute to the further understanding of hearing impairment mechanisms.