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Role of Connexin 32 (Cx32) and Hearing Loss In Charcot‐Marie‐Tooth Syndrome (CMTS)
Author(s) -
Gibson Brian D.,
Sollas Anne,
Mattiace Linda A.,
Yu Guopei,
Kim Ana H.
Publication year - 2011
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1002/lary.22277
Subject(s) - head and neck surgery , medicine , otorhinolaryngology , surgery
Objective: Evaluate the role of Cx32 and hearing loss associated with Charcot-Marie-Tooth syndrome using a Cx32 knockout (KO) mice model. Study Design: Scientific Research. Methods: Cx32 knock-out mice (KO) were compared to CBA normal hearing controls and Cx32 wild type (WT) mice to evaluate inner ear development using epifluorescent microscopy and auditory performance using auditory brainstem response (ABR) testing at approximately 3, 6, and 12 months of age. Distribution of Cx32 was compared relative to Cx26 and Cx30 using immunofluorescent staining and epifluorescent microscopy. Results: Cx32KO mice showed greater hearing loss compared to CBA controls by 4.5-6 months of age (thresholds: 51.75 +/10.3 dB verse 40 +/5 dB, respectively, p=0.0001). The difference became more pronounced with aging (13 month CBA control threshold: 41.7 +/2.9 dB verses 10-11 month Cx32KO threshold: 63.6 +/14.2 dB, p<0.0001). Distribution of Cx32 differed from Cx26 and Cx30. Cx26 and Cx30 were prominent in the spiral lamina, supporter cell region, and lateral connective tissue in the CBA, Cx32WT, and Cx32KO mice. In contrast, Cx32 showed minimal presence and solely in the supporter cell region in both the CBA and Cx32WT mice while absent in the Cx32KO mice. Conclusion: While Cx32KO mice showed normal cochlear architectural morphology, Cx32 deletion results in earlier hearing loss. This may suggest a cochlear endolymphatic dysregulation due to its location in the supporter cell region as the cause of hearing loss in CMTS, not auditory neuropathy, as Cx32 was not present in the spiral ganglion. Cx32KO mice may serve to study hearing loss in CMTS.