MMP9 and ischemia: This study revealed that siRNA homologous to MMP-2 and MMP-9 conserved region of the gene has a potential of cardioprotective factor in hearts subjected to ischemia/reperfusion injury through the reduction of MMP-2 and MMP-9 levels and activities in the heart and restoration of the balance between those proteins and their endogenous inhibitor—TIMP-4.