心肌内注射17β-雌二醇纳米粒对大鼠心梗的修复作用

objective To experimentally investigate the efficiency of direct intramyocardial administration of 17β-estradiol loaded nanoparticles on angiogenesis, infarct size and mortality after myocardial infarction (MI) in rats. Methods PLGA (poly-dl-lactic-CO-glycolic acid) nanoparticles containing 0.24% (w/w) of estradiol were prepared by a solvent evaporation method. And then release parameters were detected in vivo and vitro experiments. Myocardial infarction was induced by ligation of Ieft coronary artery in ovariectomized rats receiving either 17β-estradiol loaded nanoparticles or bare nanoparticle.one month later, microvascular density(MVD) and eNOS protein expression in myocardium of rats after MI were detected by immunohistochemistry, and infarct size in the infarct region was measured with previous experimental method. Results The 17β-estradiol release was maintained at a constant rate form PLGA nanoparticles for one month.one month later,The MVD and eNOS protein were higher in myocardium of rats after MI in 17β-estradiol loaded nanoparticles group than that in control group(P<0.05).moreover, a significant reduction in infarct size was observed in 17β-estradiol loaded nanoparticles group,compared with MI rats receiving bare nanoparticle(P<0.05). The mortality was not different in all groups(P>0.05). conclusions local intramyocardial administration of 17β-estradiol loaded nanoparticles can effectively promote angiogenesis and decrease infarct size after MI in rats,and do not increase mortality.