Cystine protects cochlear outer hair cells against glutamate toxicity

We previously reported that long-term exposure to glutamate (Glu) induced d eath of cochlear outer hair cells (OHCs). However. the mechanisms of OHC de ath induced by Glu were unclear. In the central nervous system, Glu is know n to interfere with a cystine-Glu antiporter, leading to a decrease in cyst ine uptake and reducing the intracellular glutathione level. We therefore i nvestigated the effect of cystine supplementation on degeneration of OHCs c aused by long-term exposure to Glu. Supplementation of cystine significantl y decreased the number of dying OHCs. These findings suggest that a cystine -Glu interaction may be involved in the mechanism of OHC degeneration cause d by Glu.