骨髓干细胞动员后归巢梗死心肌的实验研究

目的初步探讨骨髓干细胞动员后归巢梗死心肌的可能机制。方法结扎Wistar大鼠左冠状动脉制作急性心肌梗死(acutemyocardialinfarction,AMI)模型,用干细胞因子(SCF)动员骨髓干细胞,部分大鼠予激素干预治疗,另设AMI组为对照组(A组)。制模后24h杀死大鼠,取出心脏,免疫组化法了解归巢于梗死心肌的CD34细胞数量,心肌组织中炎症趋化因子基质细胞衍生因子(SDF-1)表达量,以及HE染色观察心肌组织学变化。结果应用SCF动员治疗后,AMI 动员组(A1组)大鼠梗死灶内SDF-1表达量明显大于AMI组和AMI 激素 动员组(A2组),同时AMI 动员组(A1组)大鼠梗死灶内CD34阳性细胞数量也明显大于另2组。而AMI 激素 动员组(A2组)的SDF-1表达量最少,其梗死灶内CD34阳性细胞数量也最少。AMI 动员组(A1组)大鼠心肌梗死程度轻,可见CD34阳性的幼稚心肌细胞样细胞。结论应用SCF动员AMI大鼠的骨髓干细胞后,其向梗死灶归巢的能力增强,较多CD34细胞迁移到缺血灶内,并向心肌细胞等分化。骨髓干细胞动员后,心肌梗死灶内SDF-1表达量上调是吸引骨髓干细胞归巢的可能机制之一。

Experimental Research on Bone Marrow Stem Cells Homing to Infarcted Myocardium After Mobilization

Objective To study the possible mechanism of bone marrow stem cells homing to infracted myocardium after mobilization. Methods Left anterior descending coronary arteries were ligated to produce acute myocardial infarction(AMI) model in wistar rats. Bone marrow stem cells were mobilized by SCF and part of rats was treated with hormone. Some AMI rats were used as control group. Hearts were harvested at 24 hour after AMI modeling for histopathological examination. Immunohistochemisty, HE stain were used to detect infiltration of CD34 cells and the expression of chemotaxis factor stromal cell-derived factor-1(SDF-1) in myocardium. Results There were a great number of monocytes infiltrating with CD34 expression by immunohistochemisty in myocardial infracted zone in mobilized rats, while there were less in other two groups. SDF-1 showed higher expression in AMI mobilized group than that of other two groups. SDF-1 expression showed the least in AMI hormone mobilized group. AMI mobilized group rats have a smaller infarction size. 24 hours after modeling, a large amount of infiltrative monocytes and regenerative myocytes with CD34 positive expression could be found in the infarction zones of the mobilized groups, while majority of the infiltrative inflammatory cells in AMI group were neutrophils and there was less infiltrative cells and myocytes with CD34 positive expression. Conclusion In AMI mobilized group, ability of bone marrow stem cells homing to infarcted myocardium increases after mobilization. SCF can mobilize many bone marrow stem cells (CD34 cells) to home to infarcted zones and differentiate to cardiomyocyte-like cells. SDF-1 is one of chemotaxis factors which attract bone marrow stem cells to home to myocardium. Higher expression of SDF-1 is the possible mechasism of bonemarrow stem cells homing to infarcted myocardium.