OXYGEN DEPRIVATION BUT NOT A COMBINATION OF OXYGEN, GLUCOSE, AND SERUM DEPRIVATION INDUCES DNA-DEGRADATION IN MOUSE CORTICAL-NEURONS IN-VITRO - ATTENUATION BY TRANSGENIC OVEREXPRESSION OF CUZN-SUPEROXIDE DISMUTASE

The present work was designed to study the possible implication of apo ptosis in ischemic neuronal death, a phenomenon that has been suggeste d to be involved in neurodegeneration following focal as well as globa l ischemia, In this study, mouse cortical neurons in primary culture w ere subjected to oxygen deprivation or oxygen, glucose, and serum depr ivation to simulate hypoxia and ''ischemia-like'' conditions; also, ce llular viability as well as DNA degradation were investigated. The res ults showed that DNA degradation occurred in neurons subjected to oxyg en deprivation but not to oxygen and substrate deprivation together, T his DNA degradation, resulting in a laddering by agarose gel electroph oresis, could be prevented by cycloheximide and actinomycin-D treatmen ts, although these inhibitors were unable to reduce neuronal death, To investigate if DNA degradation could be elicited by an intracellular free radical generation during reoxygenation, transgenic neurons overe xpressing copper-zinc superoxide dismutase were subjected to 9 h of ox ygen deprivation and analyzed after 24 h of reoxygenation, The results showed a significant attenuation of DNA degradation in these cells an d confirmed a possible relationship between reactive oxygen species an d neuronal apoptosis, This study opens the way to further investigatio ns regarding the involvement of an apoptotic process in necrotic neuro nal death, and provides some new insights into the mechanisms underlyi ng selective sensitivity of neuronal cells to oxygen and glucose depri vation.