Cardiac fibrosis in fII^MZ mice. FII^WT mice did not have any evidence of cardiac fibrosis or hemorrhage/iron deposition (A-C). However, fII^MZ animals developed evidence of cardiac fibrosis by the age of 10 weeks on both hematoxylin and eosin and Trichrome stains (D-E). At 10 weeks of age in mice, the most pronounced area of fibrosis was in the subepicardial region. Areas of fibrosis colocalize with areas of iron deposition, as shown here in Prussian blue stain (F). All scale bars represent 100 microns.