MMP9 and myocardial infarction: In FrzA transgenic mice, cardiac rupture rate was reduced from 26.4 % to 6.5 % and myocardial infarct size became smaller after myocardial infarction while the apoptotic index, early leukocyte infiltration, and MMP-2 and MMP-9 activity decreased, collagen distribution wass significantly improved and cardiac function also improved [15].