Intermediate filaments in the endolymphatic sac of the guinea pig

The expression of the five main groups of intermediate filaments and their subgroups, especially cytokeratins, was investigated in the guinea pig endolymphatic sac at the light microscopic level using immunohistochemistry. Immunostaining for cytokeratin (PKK1, PKK2, PKK3) was found in the epithelial cell layer of the sac. Vimentin was seen to stain epithelial cell layer as well as subepithelial tissue. These findings may indicate that the cytokeratins are closely related to the inner ear fluid transport. The coexpression of cytokeratin and vimentin seemed to indicate the dual function of absorption and secretion of the endolymphatic sac epithelial cell to regulate the inner ear fluid homeostasis.