Progressive degeneration of stereocilia in cochlear hair cells in hearing-impaired kuru2 mice.
BACKGROUND
We previously isolated a mouse strain, kuru2, which exhibits abnormal behavior and hearing impairment. To investigate the etiology of this impairment, the ultrastructure of the inner ear was examined.


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.


CONCLUSIONS
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.
Department of Microbiology, Jikei University School of Medicine, Tokyo, Japan. troy@jikei.ac.jp
Michiko
M
Watanabe
Nobutake
N
Akiyama
Noriko
N
Hasegawa
Yoshinobu
Y
Manome
D000818:Animals; D000831:Animals, Newborn; D002923:Cilia / Q000473:pathology* / Q000648:ultrastructure; D003433:Crosses, Genetic; D005260:Female; D006199:Hair Cells, Auditory, Inner / Q000473:pathology* / Q000648:ultrastructure; D018069:Hair Cells, Vestibular / Q000473:pathology / Q000648:ultrastructure; D034381:Hearing Loss / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008817:Mice, Mutant Strains; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D013136:Spiral Ganglion / Q000473:pathology / Q000648:ultrastructure