Fluorocitrate Neural Dystrophy of the Guinea Pig Cochlea

Abstract

All studies on primary neural degeneration in the cochlea have evaluated the end stages of degeneration or the indiscriminate destruction of both sensory cells and cochlear neurons. We have developed a model which selectively simulates the dystrophic changes denoting cochlear neural degeneration while sparing the cochlear hair cells. Such a model can be used to define more precisely the mechanism of presbycusis or the hearing loss in aging man.Twenty-two pigmented guinea pigs (200-250 gm) were perfused by the perilymphatic route as live preparations using fluorocitrate in various concentrations (15-250 ug/cc) and at different incubation times (5-150 minutes). The barium salt of DL fluorocitrate, (C6H4O7F)2Ba3, was reacted with 1.0N sulfuric acid to precipitate the barium as a sulfate. The perfusion medium was prepared, just prior to use, as follows: sodium phosphate buffer 0.2M, pH 7.4 = 9cc; fluorocitrate = 15-200 mg/cc; and sucrose = 0.2M.