Extracellular superoxide dismutase deficiency worsens outcome from focal cerebral ischemia in the mouse

The role of endogenous extracellular superoxide dismutase (EC-SOD) was examined in a murine model of transient focal cerebral ischemia. Homozygous EC-SOD deficient (EC-SOD −/−; n=18) and wild type (EC-SOD +/+; n=19) littermates were anesthetized with halothane and subjected to 50 min of intraluminal middle cerebral artery occlusion with pericranial temperature maintained at 37.0°C. After 24 h of reperfusion, resultant hemiparesis and cerebral infarct size were measured. Total infarct volume was 81% greater ( P=0.03) and hemiparesis was more severe ( P=0.01) in EC-SOD −/− versus EC-SOD +/+ mice. The worsened ischemic outcome observed in EC-SOD −/− mice is consistent with prior work which found transgenic EC-SOD overexpressing mice to exhibit enhanced tolerance to focal ischemia. The results suggest that endogenous antioxidant activity in the extracellular compartment plays an important role in the histologic/neurologic response to focal cerebral ischemia.