(A) The CD44 ligand, HA, was elevated at d1 post-MI in the MMP-12 inhibitor (MMP-12i) group compared to the saline group, and these levels were sustained through d7 post-MI. n=6/group. *p<0.05 vs. day 0, #p<0.05 vs. respective saline. (B) MMP-12i increased protein expression of caspase 3, an apoptosis marker. Peritoneal macrophages were used as a positive control (labeled as C). (C) Immunohistochemistry analysis showed that cleaved caspase 3 expression was reduced in the infarct area of MMP-12i group at d7 post-MI compared to the saline MI group. (D) CD18, an adhesion molecule that suppresses apoptosis, was upregulated in the MMP-12i group compared to saline at d7 post-MI. Peritoneal macrophages were used as a positive control (labeled as C). n=5–10/ group, *p<0.05 vs. day 0 and #p<0.05 vs. d7 saline. Scale bar is 200 μm.