Ventricular remodeling in a mouse model of myocardial infarction

Abstract

We investigated the suitability of studying ventricular remodeling in a mouse model of myocardial infarction (MI). We performed left coronary ligation ( n = 22) or a sham procedure ( n = 21) on normal C57BL/6J mice. Six weeks later, animals underwent echocardiography and hemodynamic evaluation. Left ventricular (LV) volume at a common distending pressure was calculated from passive pressure-volume curves. The MI group exhibited lower systolic blood pressure ( P < 0.05), higher LV end-diastolic pressure ( P < 0.05), and lower peak first derivative of LV pressure (dP/d t, P < 0.05) than the sham group. Mice with moderate (<40%, n = 11) and large (≥40%, n = 11) MIs displayed increased LV mass-to-body weight ratio ( P < 0.02 and P < 0.01, respectively, vs. sham group), whereas only the large-MI group exhibited increased right ventricular mass-to-body weight ratio ( P < 0.01). LV volumes were increased in the moderate-MI group ( P= 0.059 vs. sham group) and to a much greater extent in the large-MI group ( P < 0.0001 vs. sham group). The moderate- and large-MI groups also exhibited increases in LV end-diastolic diameter ( P < 0.03 and P < 0.0001, respectively, vs. sham group) and LV end-systolic diameter ( P< 0.01 and P < 0.0001, respectively, vs. sham group) with decreased fractional shortening ( P < 0.01 for both). These data demonstrate ventricular remodeling in a mouse model of MI and confirm the feasibility of quantifying indexes of remodeling in vivo and postmortem. This model will be of particular usefulness when applied to transgenic strains.