Cardiac hypertrophy and fibrosis in aged α<i>MHC-Cre/Foxm1^fl/fl</i> mice.

<p>Foxm1 mRNA was significantly decreased, while CaMKIIδ mRNA was unaltered, in hearts of old WT mice compared to young mice as shown by qRT-PCR (A). Old <i>αMHC-Cre/Foxm1^fl/fl</i> mice had significant cardiac hypertrophy as indicated by increased heart weight-to-body weight ratios (E) and increased cardiomyocyte area (F). Cardiomyocyte area was visualized and measured in WGA stained sections using 50 cardiomyocytes from random fields (B). Cardiac fibrosis was increased in old <i>αMHC-Cre/Foxm1^fl/fl</i> mice as shown by Masson's Trichrome staining (C, D). qRT-PCR analysis showed increased αSMA, fibronectin, vimentin and MMP9 and decreased Hey2 mRNA levels in hearts of old <i>αMHC-Cre/Foxm1^fl/fl</i> mice compared to age-matched control mice (G). Significant differences (p<0.05) were indicated by asterisk. “N” was 7 young and 6 old wildtype mice (A) and 6 control and 4 <i>αMHC-Cre/Foxm1^fl/fl</i> mice (E–G). Magnifications were 40x (B, D) and 10x (C).