Postnatal Development and Maturation of the Vestibular Organ in Dominant-Negative Connexin 26 Transgenic Mouse

Backgrounds: Immunohistochemical studies have revealed that connexin 26 (Cx26) exists not only in the cochlea but also in the vestibular organs. K+ cycling involving gap junction protein Cx26 in the vestibular labyrinth, which is similar to that in the cochlea, is thought to play a fundamental role in endolymph homeostasis and sensory transduction. Methods: We analyzed the morphological and functional development of the vestibular organ in Cx26 transgenic mice between 0 days after birth (P0) and P140, which was compared with that of littermate control mice (non-Tg). Results: The gross structure of the inner ear in non-transgenic and transgenic mice revealed no hydrops, no defects, no degeneration in either the cochlea or the vestibule throughout the postnatal period. Light microscopic observations in the sensory epithelium revealed normally developed and matured utricula macula, saccular macula, and ampulla in the transgenic mice, which were very similar to those of the nontransgenic mouse. Conclusions: The present study clearly demonstrated that postnatal development and maturation in the vestibular organ were morphologically and functionally completed in Cx26 transgenic mice.