[The changes in superoxide anion production in neutrophils on ischemia-reperfusion]

It is generally known that ischemic reperfusion injury is caused by cell membrane injuries due to superoxide. The present study was carried out to clarify an increase of superoxide production in human neutrophils in state of hypoxia and hyperoxia in vitro. Superoxide of neutrophils was studied at various PO2 values (air, 100% O2, 50% O2, and 100% N2 gas) by chemiluminescence method. The superoxide production (O2-) rates were 84% (air), 84% (100% N2), 87% (100% O2) and 84% (50% O2), respectively. At these stages, PO2 values were 178, 36, 764 and 370 mmHg, respectively. Since superoxide is generated in mitochondria under PO2 of 1 mmHg, it was considered that these different values of PO2 (100% N2, 100% O2 and 50% O2) do not influence the superoxide production. Other factors, such as PAF or cytokine, were speculated to increase superoxide production.