Efficacy and Safety Evaluation of PC-SOD for Injection in Reducing Myocardial Reperfusion Injury

Inclusion Criteria: 1. Age 18 - 75 years, male or female; 2. Meeting the diagnostic criteria of AMI (chest pain for over 10 - 20 min, which could not be relieved completely by oral nitroglycerin; ST elevation ≥ 2 mm in two or more adjacent leads in leads V1-V5 ); 3. Killip classes I or II; 4. Coronary angiography possible within 6 hours of onset; 5. Emergent coronary angiography showing occlusion in left anterior descending artery (TIMI grade 0 - 1); patients with this symptom could also be included despite inconformity to criterion 2); 6. Willingness to participate in the trial with ethical approval and informed consent provision. Exclusion Criteria: General exclusion criteria 1. Previous history of myocardial infarction; 2. History of myocardial revascularization before screening; 3. Thrombolytic treatment after onset; 4. Cardiogenic shock; 5. Cardiopulmonary resuscitation between onset and screening; 6. Atrial fibrillation, atrioventricular block (degree I, II or III), and other severe arrhythmias that cannot be corrected and affect hemodynamics; 7. Suspected of aortic dissection; 8. Diabetes with long-term insulin use, or definite macrovascular or small vascular lesions (stroke, diabetic nephropathy, retinopathy, diabetic foot, and etc.); 9. History of major surgeries within 6 months; 10. History of stroke within 6 months; 11. History of immune disorders within 6 months (such as cancer, lymphoma, HIV or hepatitis), or use of immunosuppressive agents at doses that can cause immunosuppression within 10 days; 12. Clinically significant diseases of the respiratory, digestive, blood, immune, endocrine, nervous or urinary systems (renal insufficiency in particular), and diseases that might cause serious risk to patients based on the judgement of researchers; 13. Allergy to two or more drugs and/or foods, or known allergy to sucrose; 14. Any contraindications for cardiac MRI, such as implantation of metal objects (pacemakers and/or implantable defibrillators; insulin pumps, or any other electronic devices; cerebral clips, aneurysm clips, and etc.), and other contraindications (such as claustrophobia); 15. Pregnancy or lactation in women; 16. Participation in other clinical trials within 3 months; 17. Situations considered unsuitable for enrollment (such as disease condition or patient compliance). Exclusion criteria for angiography 1. Occlusion of left main artery; 2. Apart from the left anterior descending branch, other blood vessels requiring revascularization in the same period or within a month.