Surface structure of stria vascularis in the guinea pig cochlea. Normal morphology and atoxyl-induced pathologic changes.

The normal cell surface of the hexagonal epithelial (marginal) cells covering the stria vascularis is characterized by numerous microvilli and a few depressions. The cells at the spiral prominence are similar to the epithelial cells of the stria vascularis but are more spindle shaped and without depressions on the surface. Atoxyl treatment results in damage to the epithelial cells of the stria vascularis by loss of microvilli and depressions. Later during the degeneration, protrusions from the cell surface occur and the cell borders become fragmented. The cells of the spiral prominence are far less damaged. In advanced stages of strial damage great herniations including several adjacent cells may balloon out into the endolymphatic space.