静脉移植人脐血细胞促进家兔急性心肌梗死血管再生

Intravenous administration of human umbilical cord blood cells (HUCBC) enhances angiogenesis in rabbits with acute myocardial infarction

目的探讨静脉移植人脐血细胞(HUCBCs)对家兔急性心肌梗死(AMI)血管再生的影响。方法家兔随机分为(1)假手术组:冠状动脉左前降支穿线不结扎;(2)模型组;(3)细胞移植组:结扎左前降支建立急性心肌梗死模型。各组均15只。造模后24 h,细胞移植组经耳缘静脉注入含2×107个人脐血单个核细胞的细胞悬液0.5 mL;假手术组、模型组同法注入等量生理盐水。移植后1、2和4周超声检测心功能;免疫组化检测心肌BrdU阳性细胞及Ⅷ因子染色检测血管新生;RT-PCR检测心肌组织VEGF mRNA表达。结果移植组心功能明显改善,左室短轴缩短率及左室射血分数均明显升高(P<0.05);移植组心梗区毛细血管密度显著增加(P<0.01),BrdU阳性细胞分布于其梗死周边区域;移植后心肌组织VEGF mRNA表达显著上调(P<0.01)。结论促进血管再生是脐血细胞移植治疗急性心肌梗死的主要机制之一。

Objective To investigate the effects of intravenous administration of human umbilical cord blood cells（HUCBC） on the angiogenesis in rabbits with acute myocardial infarction.Methods Rabbits were randomly divided into sham operation group,model and cell transplantation groups with 15 animals in each group.Rabbits were performed anterior descending branch braid without ligation in sham group;Rabbits acute myocardial infarction models were prepared in cells transplantation group and in model group.24 hours after model preparation,0.5 mL HUCBCs suspension（containing 2×107 cells） was intravenously administrated into rabbits in the cell transplantation group.The same volume of saline was administrated into the other two groups.Cardiac functions were performed by echocardiography at 1st,2nd and 4th week after transplantation.The survival of transplanted cells and microvessle density in the myocardium were identified by immunohistochemistry.The expression of VEGF mRNA in the myocardium was examined by RT-PCR.Results Transplantation of HUCBC improved left ventricular function indexes such as LVFS,LVEF at all 3 examinations（P0.05）;Immunohistochemistry showed that BrdU positive cells were only found in the transplantated rabbits.Compared with control group,there was a signifi cant increase of microvessle density within the boundary of infarcted myocardium in cell transplantation rabbits（P0.01）.Com-pared with control group,there was an markedly higher level of the expression of VEGF mRNA in the transplantated group（P0.01）.Conclusion Angiogenesis induced by the HUCBCs might be one of main mechanisms for stem cell transplantation for myocardial infarction.