SOD1 and diabetes mellitus: We observed a remarkable compensatory increase of plasma SOD activity in diabetes when reperfusion last for a longer time (from 2 hours to 3 hours), which is similar to our previous study showing that in 9 weeks of STZ-induced diabetic rats, a compensatory increase in myocardial total antioxidant capacity occurred as a consequence of the increase of cytosolic Cu/Zn-SOD, but yet it was not sufficient to prevent hyperglycemia-induced oxidative stress [34].