Serum CK (A), MPO (B) and MDA (C) in serum were measured (n = 5-10). CK: creatine kinase, MPO: myeloperoxidase; MDA: malondialdehyde; Sham: sham operation; Vehicle +I/R: saline pre-treatment for 7 days followed by 30 minutes of myocardial ischemia and 24 hours of reperfusion, G12.5+I/R, G25+I/R or G50+I/R: GYY4137 pre-treatment at 12.5 mg/(kg·day), 25 mg/(kg·day) or 50 mg/(kg·day) for 7 days followed by 30 minutes of myocardial ischemia and 24 hours of reperfusion. *P<0.05, **P<0.01.