MMP9 and myocardial ischemia: HSYA could reverse the haemodynamic alteration, enhance the survival rate, alleviate the myocardial damage, and promote the angiogenesis in the ischemic myocardium by enhancing expression of nucleolin and thus upregulating expressions of vascular endothelial growth factor A (VEGF-A) and matrix metallopeptidase 9 (MMP-9) in the myocardial ischemia (MI) rats induced by occlusion of left anterior descending coronary artery (LAD) [9].