内源骨髓间充质干细胞在心肌梗死后的迁移、归巢与分化

背景：目前的大多数研究主要集中在移植外源干细胞来源的心肌细胞对受损心肌进行修复与再生，而有关内源干细胞迁移、归巢及分化的研究比较少。目的：观察内源骨髓间充质干细胞在心肌梗死后迁移、归巢以及分化情况。方法：成年雌性C57BL/6小鼠随机分为2组：心肌梗死组(n=4)小鼠建立骨髓重建模型，于骨髓重建4周后行冠状动脉左前降支结扎术建立急性心肌梗死模型，1周后处死；对照组(n=3)小鼠进行单纯骨髓重建，于骨髓重建4周后处死。取心脏组织，采用免疫荧光染色检测心肌特异性蛋白Troponin Ⅰ的表达，观察心肌梗死后表达绿色荧光蛋白的骨髓间充质干细胞在心肌组织中的分布、分化情况。结果与结论：骨髓重建小鼠心肌梗死组与对照组均可见到发绿色荧光的骨髓间充质干细胞，心肌梗死组骨髓间充质干细胞数量比对照组明显增多。两组切片均可见部分骨髓间充质干细胞呈GFP、Troponin Ⅰ和PI三阳性，心肌梗死组三阳性的细胞比对照组明显增多，表明心肌梗死后内源骨髓间充质干细胞能迁移、归巢到受损的心肌组织并获得心肌分化表型。

Migration,homing and differentiation of endogenous bone marrow mesenchymal stem cells after myocardial infarction

BACKGROUND: Most of studies have focused on the transplantation and regeneration of exogenous stem cells-derived myocardial cells after myocardial infarction, but relatively few studies address the migration, homing and differentiation of endogenous stem cells.OBJECTIVE: To observe the migration, homing and differentiation of endogenous bone marrow mesenchymal stem cells after myocardial infarction. METHODS: Adult female C57BL/6 mice were randomized into two groups: myocardial infarction group (n=4), in which, the left anterior descending branch of the coronary artery was ligated to establish acute myocardial infarction models at 4 weeks after bone marrow remodeling, and 1 week later, the model mice were sacrificed; control group (n=3), in which, the mice were subject to bone marrow remodeling and then sacrificed after 4 weeks. Heart tissues were extracted from two groups followed by immunofluorescent detection of Troponin I expression, and the distribution and differentiation of bone marrow mesenchymal stem cells positive for green fluorescent protein after myocardial infarction were observed.RESULTS AND CONCLUSION: After histological and immunohistochemical examination, bone marrow  mesenchymal stem cells positive for green fluorescent protein were observed in both myocardial infarction group and control group, while more positive cells were seen in the myocardial infarction group. Some bone marrow mesenchymal stem cells in both two groups were positive for green fluorescent protein, Troponin I and PI. However, more triple-positive cells were observed in the myocardial infarction group compared to the control group. Endogenous bone marrow mesenchymal stem cells can migrate, home to the damage myocardium and acquire cardiogenic phenotype after myocardial infarction.