Figure 2.
(a) Representative examples of staining with Masson’s trichrome and picrosirius red under polarized light of the infarcted region, 15 days after experimental MI (WT is represented by the left panels, MMP-9 KO by the right panels). Picrosirius red staining demonstrated the characteristic bright yellow of collagen fibrils under polarized light, with less deposition of picrosirius red–stained collagen in MMP-9 KO samples than in WT samples (scale bar: 200 μm). (b) Collagen volume fraction from picrosirius red–stained myocardium as percentage of stained tissue in muscle areas and connective tissue in the visual field of the section. (c) Collagen content of apical myocardium after MI in infarct size matching WT and KO animals. AP < 0.05.