Ultrastructure of the stria vascularis and Reissner's membrane in experimental hydrops.

A time-sequence study was made of the early ultrastructural changes of the stria vascularis and Reissner's membrane in the guinea pig after obliteration of the endolymphatic sac and duct. Pathological alterations of both the stria vascularis and Reissner's membrane were found to start in the apex of the cochlea. The morphological changes of the stria vascularis were characterized by an increase of vesicles in the marginal cells and by intercellular edema, followed by vacuolization and atrophy of marginal and intermediate cells. In Reissner's membrane extensive gaps in the mesothelial cell layer were observed together with intracellular pathology of the epithelial cells. The significance of these ultrastructural changes in the stria vascularis and Reissner's membrane with regard to the pathophysiology of the endolymphatic hydrops is discussed.