雌激素对心肌梗死大鼠外周血干细胞及血管生成的影响

目的探讨雌激素对急性心肌梗死大鼠外周血干细胞和心肌血管生成的影响。方法结扎去卵巢SD大鼠左冠状动脉制作急性心肌梗死模型,给予苯甲酸雌二醇干预治疗,分别于急性心肌梗死24h后免疫组化法检测归巢心肌的CD34+细胞数量;于d1、3、7流式细胞术测定外周血CD34+细胞数,免疫组化法测定心肌中基质细胞衍生因子(stromalcell-derivedfactor,SDF-1)的表达,分析心梗4wk后心肌组织中毛细血管密度判断血管新生情况。结果与卵巢完整大鼠相比,去卵巢大鼠心梗后外周血和心肌组织中CD34+细胞数、SDF-1的表达和4wk后毛细血管密度明显降低,雌激素干预各组上述指标明显升高,其中,雌激素替代组最高。结论雌激素可促进大鼠心肌梗死后外周血骨髓干细胞的动员和归巢,增加毛细血管密度,改善预后,其机制可能与提高心肌SDF-1表达有关。且采用心肌梗死前雌激素替代疗效优于心肌梗死后雌激素治疗

Effects of estrogen on peripheral blood stem cells and angiogenesis in myocardial infarction rats

Aim To study the influence of estradiol on peripheral blood stem cells and angiogenesis in a rat model of myocardial infarction.Methods Acute myocardial infarction(AMI)model was bulit by ligation of left anterior descending coronary in ovariectomized SD rats.Then,they were treated with different doses of estradiol benzoate.CD34+ cells in myocardium at 24 h after AMI were detected by immunohistochemistry,and CD34+ cells in peripheral blood were measured by flow cytometry on day 1,3 and 7 after AMI.The expression of stromal cell-derived factor-1(SDF-1)in myocardium on day 1,3 and 7 after AMI and capillary density in myocardium at 28 days after AMI were evaluated by immunohistochemistry.Results CD34+ cells in peripheral blood and myocardium,the expression of SDF-1 and capillary density at 4 weeks after AMI in ovariectomized rats were obviously lower than those in ovary intact rats.However,after indication with different doses of estrogen,CD34+ cells in peripheral blood and myocardium,the expression of SDF-1 and microvascular density were increased in ovariectomized rats with AMI,this effect was strongest especially in estrogen replacement therapy group.Conclusions Estrogen could improve the mobilization and homing of bone marrow stem cells into myocardium,increase capillary density and improve prognosis after AMI,and this mechanism could be mediated by promotion of expression of SDF-1 in myocardium.Moreover,the effect of estrogen replacement before AMI was better than estrogen therapy after AMI.