R92Q-Myc mice demonstrate myocellular disarray and fibrosis. Cardiac sections from 4- to 5-month-old non-Tg (a), R92Q-Myc-67% (b and c), WT-Myc (d), and R92Q-Myc-92% (e and f). a, b, d, and e were stained with hematoxylin and eosin. Note markedly pleiotropic nuclei and myocellular degeneration in b and e. e also demonstrates clear myocellular disarray and inflammation. c and f are stained with Masson’s trichrome and demonstrate dose-dependent myocardial fibrosis. All panels ×400.