Cochlear pathology of the circling mouse: a new mouse model of DFNB6.
CONCLUSIONS
The circling mouse (cir/cir) has phenotypes which follow the pattern of neuroepithelial defects of deafness from 10 days after birth. The cir mouse is defective in Tmie gene, the function of which should be further elucidated.


OBJECTIVE
We previously reported a recessive mutation of deafness called circling mice (cir/cir). The present study focused on investigating phenotypes and histological findings of the cochlea in circling mice with respect to age.


METHODS
In order to analyze cochlear pathology over time, five different age groups of circling mice were examined (10, 18, 21, 35, and 90 days old). The organs of Corti and spiral ganglion neurons in basal and middle turns were evaluated.


RESULTS
The pathology of the organ of Corti followed the pattern of neuroepithelial defects. Hair cells in organs of Corti had degenerated in circling mice at 10 days old, in a time-dependent manner. Scanning electron microscopy (SEM) showed that stereociliary bundles were irregular in size and had shortened at 10 days, and that this degeneration was complete at 21 days. The number of spiral ganglion neurons significantly reduced with age. RT-PCR analysis indicated that the transmembrane inner ear gene (Tmie) was absent in various organs in circling mice.
Chung
Won-Ho
WH
Department of Otorhinolaryngology-Head and Neck Surgery, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul.
Kim
Ki Ryung
KR
Cho
Yang-Sun
YS
Cho
Do-Yeon
DY
Woo
Ji Hwan
JH
Ryoo
Zae Young
ZY
Cho
Kyoung In
KI
Hong
Sung Hwa
SH
D000367:Age Factors; D000818:Animals; D003638:Deafness / Q000235:genetics* / Q000473:pathology*; D004195:Disease Models, Animal; D005808:Genes, Recessive; D006198:Hair Cells, Auditory / Q000473:pathology; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D051379:Mice; D008818:Mice, Neurologic Mutants / Q000235:genetics*; D008855:Microscopy, Electron, Scanning; D009043:Motor Activity / Q000502:physiology; D009410:Nerve Degeneration / Q000235:genetics / Q000473:pathology; D046569:Neuroepithelial Cells / Q000473:pathology; D009474:Neurons / Q000473:pathology; D009925:Organ of Corti / Q000473:pathology*; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013136:Spiral Ganglion / Q000473:pathology*; D013239:Stereotyped Behavior / Q000502:physiology; D013550:Swimming
D008565:Membrane Proteins; C466299:TMIE protein, human