During myocardial ischemia/reperfusion (I/R), the generation of reactive oxygen species (ROS) contributes to post-reperfused cardiac injury and contractile dysfunction. Activation of NADPH oxidase (NOX) during reperfusion generates ROS, and exacerbates I/R injury. We hypothesize that reducing ROS formation through inhibition of NOX will attenuate myocardial I/R injury in isolated perfused rat hearts subjected to I(30min)/R(45min) compared to untreated I/R hearts. The cell-permeable NOX inhibiting peptide, gp91 ds/tat (RKKRRQRRR-CSTRIRRQL-Amide, MW=2452 g/mol, 20μM, n=5), significantly improved post-reperfused cardiac function compared to controls (n=15,
