In vivo measurement of oxygen-derived free radicals during reperfusion injury.

By use of an optimized cytochrome c-based biosensor, superoxide radical production was measured continuously in vivo. The aim of this study was the online detection of superoxide concentration during reperfusion after a variable time of ischemia. Measurements were performed by placing the detecting sensor into gastrocnemius muscle tissue. Ischemia was induced by clamping the vena and arteria femoralis. Current response of the sensor was recorded continuously as an equivalent for superoxide concentration. Ischemia times varied from 5 to 120 minutes. The minimum ischemia time to record superoxide production was 10 minutes. By inducing longer periods of ischemia, an increase in superoxide concentration reached its highest levels at 2 hours. Furthermore, the total time of superoxide production after reperfusion depended on the total time of ischemia. Copyright 2002 Wiley-Liss, Inc.