Micro-lesions in Reissner's membrane evoked by acute hydrops.

In some pathological conditions excessive amounts of endolymph can accumulate and cause swelling, hydrops, of the membranous labyrinth. Reissner's membrane in the cochlea will distend and may even rupture. We have studied the effects of acute hydrops, followed for up to 5-6 h, in a preparation that allows continuous monitoring of structural alterations in individual cells in Reissner's membrane. This is accomplished by using laser confocal microscopy on the membrane visualized by labeling its cells with fluorescent dyes. In specimens subjected to hydrops it was observed that discrete structural defects developed in Reissner's membrane. These were seen as lesions in single cells or in groups of cells in the epithelial layer. It is suggested that through these micro-lesions the electro-chemical environment of the organ of Corti can be altered causing hearing loss and tinnitus during hydrops.