E HPLC detection of a superoxide probe oxidized dihydroethidium (DHE) product in sham and I/R injury heart tissue (30-min ischemia followed by 30-min reperfusion), 2-hydroxyethidium (EOH), a specific product for superoxide anion radical. *p < 0.0001, n = 5 in each group.F In the same samples of (E), HPLC detection of ethidium (E), oxidized by other reactive oxygen species such as H2O2 (mainly) and ONOO. *p = 0.0001, n = 5 in each group. 