The molecular basis of oxidative stress-induced cell death in an immortalized retinal ganglion cell line.

PURPOSE To characterize the molecular basis of oxidative stress-induced death, a process that has been implicated in several chronic eye diseases, in RGC-5 cells, an immortalized retinal ganglion cell (RGC) line. METHODS The responses of RGC-5 cells to oxidative stress induced by three different treatments--glutathione depletion, tert-butyl peroxide addition, and hydrogen peroxide addition--were examined and compared. The level of cell death was monitored with the MTT assay. The effects of glutathione depletion on the intracellular levels of glutathione, reactive oxygen species, and calcium were determined. The type of cell death was assessed with assays for DNA fragmentation and caspase activation. Compounds that were shown to be protective of central nervous system-derived nerve cells exposed to oxidative stress were tested to see whether they could also protect the RGC-5 cells. In addition, several compounds that have been found to be protective in primary cultures of RGCs or in animal models of retinal dysfunction were tested against each of the inducers of oxidative stress. RESULTS The cell death triggered by all three inducers of oxidative stress shared several features, suggesting that there is a final common pathway of oxidative stress-induced death in the RGCs. In addition, several compounds were identified that protected RGCs from multiple forms of oxidative stress. CONCLUSIONS The RGC-5 line is an excellent model for studying mechanisms of RGC death in response to oxidative stress and for the identification of neuroprotective compounds.