Abstract: Objective To investigate the expression of connexin29 （connexin 29, Cx29）in mice cochlea and explore the reason why mutation of Cx29 caused deafness. MethodsAdult wild type mice C57 were decapitated and their cochleas were dissected. After a series of preparations, frozen cochlea sections were cut (7μm). Immunofluorescent labeling and colabeling of Cx29 with neurofilament (NF), myelin associated glycoprotein (MAG) and glial fibrillary acidic protein (GFAP) were applied to the sections. Labeled samples were observed by a fluorescent microscope. ResultsIn low-magnification view, Cx29 strongly labeled tracts where the auditory nerve travels inside the cochlea until the border was marked by the glial junction. The stria vascularis was faintly stained. Views obtained at higher magnification showed Cx29 expressed at the myelin of the spiral ganglion neurons and the auditory nerve fibers inside cochleas. Colabeling immunostaining showed MAG expressed in the auditory nerve inside and outside the cochlea and co-expressed with Cx29 only in the auditory nerve inside the cochlea in circular immuno-staining patterns. GFAP was only expressed in the auditory nerve in the brainstem outside the cochlea. There were no co-expressions of GFAP and Cx29. The antibody against neuro-filament gave an immuno-staining pattern of solid dots which were encircled by Cx29-positive pixels. Conclusion Cx29 strongly expresses in mice cochlea. It suggested that Cx29 should play an important role in the function of mice cochlea.

Key words: Connexin29, Myelin, Cochlear Schwann cells, Spiral ganglion neuron, Cochlea