Oxygen free radicals have been indirectly implicated in reperfusion in
jury following ischemia in the isolated rabbit heart. The authors move
d to detect free radicals in an isolated rat heart model as a prerequi
site to studying its effects during ischemia and reperfusion. Several
different spin trapping agents and electron paramagnetic resonance (EP
R) spectroscopy were used to detect free radicals being generated duri
ng ischemia and reperfusion, The possible roles of ferrous iron and hy
drogen peroxide generation in reperfusion injury were also investigate
d No free radical ''bursts'' were detected with any of the spin traps
used in this model during ischemia or reperfusion. Hydrogen peroxide a
nd hydroxyl free radicals do not appear to be involved in tissue reper
fusion injury. This study suggests that free radicals are not produced
in clinically significant quantities under these conditions to accoun
t for ischemic myocardial damage.