ALTERATIONS IN REACTIVE OXYGEN, PH, AND CALCIUM IN ASTROCYTOMA-CELLS DURING LETHAL INJURY

Exposure of cultured human astrocytoma cells to iodoacetic acid result s in rapid depletion of cellular ATP and cell death. Pathophysiologica l changes in the injured cells, including formation of reactive oxygen species (ROS), cell viability, glutathione, pH, and cytosolic calcium , were characterized at the cellular level via fluorescence microscopy . After iodoacetic acid treatment, cellular ATP and intracellular glut athione fell sharply to undetectable levels within 2 h. ROS, as detect ed by the oxidation of dichlorofluorescein, appeared in 20 min and rea ched a maximum before the loss of membrane integrity. Cells became aci dotic within 10 min. Cytosolic free calcium concentration exhibited a slow increase and then a sharp influx shortly before the rupture of th e cell membrane. The addition of lipophilic antioxidants, nordihydrogu aiaretic acid or the troloxamine U-78517F, eliminated the accumulation of ROS and delayed the onset of cell death without affecting other pa rameters observed in the early phase of the injury. We conclude that R OS is formed and may play important roles during lethal cell injury ca used by energy depletion.