As shown in Fig. 5A, myocardial ischemia caused a robust increase in myeloperoxidase (MPO) activity, a specific marker of local neutrophil activity, in comparison with sham-operated rats (56.18±8.01 mU MPO/tissue g, 16.92±4.11 mU MPO/tissue g, respectively; P<0.05). Here, MPO is linked to myocardial ischemia.