MMP2 and myocardial infarction: Western blot analysis of lysates from the left ventricular infarct zone showed that the protein expression of alpha-smooth muscle actin (α-SMA, a marker of Myofbs), transforming growth factor beta 1 (TGF-β1), Vimentin (a marker of fibroblast), and Collagen I were significantly upregulated on post-MI day 28, while the protein expression of matrix metalloproteinase 2 (MMP2), an enzyme known to degrade and remodel ECM, was significantly increased on days 7 and 14 and decreased to a normal level on day 28 (Figure S1Q and S1R).