ATM deficiency decreases expression of matrix metalloproteinase 9 (MMP-9) in the noninfarct region 28 days post-MI. Total LV lysates, prepared from sham, noninfarct (Non), and infarct (Inf) regions 28 days post-MI, were analyzed by Western blot using anti-MMP-2 (A) and anti-MMP-9 (B) antibodies. Top: autoradiograms indicating immunostaining for MMP-2, MMP-9, and GAPDH. Bottom: quantitative analyses of MMP-2 and MMP-9 normalized to GAPDH (*P < 0.05 vs. respective sham, #P < 0.05 vs. respective Non, $P < 0.05 vs. WT-Non; n = 5–6).