Cytoskeletal Organization of the Human Inner Ear: I. Expression of Intermediate Filaments in Vestibular Organs

Abstract

The distribution of intermediate filament proteins in cryosectioned vestibular organs of 14th-18th gestation week old human fetuses was analyzed at the light microscopic level using monoclonal antibodies (mAbs) against vimentin, cytokeratins (CK) (three different mAbs were used: PKK-1 detecting CKs 8,18 and 19; PKK-2 detecting CKs 7,17 and 19; and PKK-3 detecting CK 18), neurofilament proteins, glial fibrillary acid proteins (GFA) and desmin. Vestibular hair cells had a weak positivity for vimentin whereas supporting cells in all vestibular organs had strong positivity except those in the epithelial lining of the endolymphatic space outside the vestibular organs. Considerable variations in positivity for different subgroups of cytokeratins occurred in the epithelial lining of the endolymphatic space, although morphologic differences in cell configuration between adjacent cells were not distinguished. One type of vestibular ganglion cells showed strong positivity for neurofilament proteins whereas the other, major cell population lacked this immunoreactivity. However, both types of ganglion cells contained vimentin. GFA and desmin were lacking according to our monoclonal antibodies. Our characterization of intermediate filament proteins shows that the cells of the inner ear (also cells of the same type according to routine light microscopy and electron microscopy) have an extremely high degree of complexity of their cytoskeleton.

Key Words:

• human
• inner ear
• vestibule
• embryonic
• cytoskeleton
• intermediate filaments