Objective: To study the influence of estradiol on myocardial angiogenesis and the expression of estrogen receptors in a rat model of myocardial infarction.
Methods: Acute myocardial infaction (AMI) model was established by ligation of left anterior descending coronary in ovariectomized SD rats, which then were treated with different doses of estradiol Benzoate. Estradiol concentration in serum was measured by Radioimmunoassay before AMI and 4 weeks later, microvascular density in myocardium was evaluated with detection of expression of VIII factor by Immunohistochemistry, and estrogen receptor alpha and beta protein in the myocardium were detected with Western blot at 28 d after AMI.
Results: Estradiol levels in serum significantly degraded after ovariectomized, but increased after the treatment of different doses of estradiol. Microvascular density in myocardium 4 weeks after AMI in ovariectomized group was obviously lower than that of acute myocardial infarction group and estrogen therapy groups. Estrogen replacement therapy group had the highest microvascular density. The expression of estrogen receptor alpha and beta protein in the myocardium showed significant different, which was the highest in estrogen replacement therapy group and the lowest in ovariectomized group.
Conclusion: Estrogen improves myocardial angiogenesis in rats after AMI, this effect may be related to the expression of estrogen receptor a and beta in myocardium.