Effects of aging on ventricular remodeling and cardiac rupture after acute myocardial infarction in mice / 中华老年医学杂志

ABSTRACT

Objective To explore the effects of aging on ventricular remodeling and cardiac rupture after acute myocardial infarction in mice. Methods　Male C57BL/6 mice of 3 months and 12 months old were randomly divided into sham operation group and myocardial infarction(MI)group.Following acute myocardial infarction(AMI)modeling induced by open-chest surgery,the events of cardiac rupture were monitored and the echocardiography and hemodynamics were performed on the 7th day after surgery.Zymography,immunohistochemical method and pathological staining were used to measure the activity of matrix metalloproteinases(MMPs),the content of collagen and the degree of inflammatory cell infiltration on the 3rd and 7th days after surgery,respectively. Results　The incidence of cardiac rupture was higher in elderly group than that in young group(38.0% vs.16.0%,X2=6.139,P＜0.05).Compared with young group,significant infarct expansion,left ventricular (LV)remodeling and hemodynamic deterioration were showed in elderly group on the 7th day after surgery(t=5.754,P＜0.05).The degree of inflammatory cell infiltration and the expression of MMP-9 were significantly increased in elderly group on the 3rd day following AMI modeling(P＜0.05),and the collagen content and the expression of type Ⅲ collagen were significantly increased (P＜0.05)compared with young group. Conclusions　Aging is a risk factor for post-infarct cardiac rupture in the mice model.The mechanisms which are responsible for this age-related difference of cardiac rupture are related to increasing degree of inflammatory cell infiltration, overexpression of MMP-9 and type Ⅲ collagen and aggravated early LV remodeling.