论文部分内容阅读
目的:探索移植到心梗部位的间充质干细胞是否通过其旁分泌效应促进心脏干细胞迁移至心梗部位。方法:间充质干细胞(MSC)特征经流式细胞术鉴定其表面标志物特征及多向诱导分化实验确认其干性。经体外Transwell分析心脏干细胞迁移特征,利用VEGF,HGF及SDF-1α等受体特异阻断剂观察其在心脏干细胞迁移中的作用。在体利用左冠状动脉前降之结扎法复制心肌梗死模型。心梗后7 d,植入MSC到心梗及周边部位。细胞移植7 d后,流式细胞术分析其外周血中c-kit阳性的干细胞含量,免疫荧光组织化学技术分析心梗部位c-kit阳性的干细胞数目,同时行Western Blot分析心脏VEGF,HGF及SDF-1α的表达,一月后心导管技术测量心功能及胶原染色和HE染色确定梗死面积。结果:移植的MSC增加了心梗部位VEGF,HGF及SDF-1α的表达,并动员c-kit阳性的干细胞迁移至心梗部位。与对照组相比,MSC移植组明显降低了心梗面积,显著增加了血管密度,明显改善了左室心脏功能。体外迁移实验发现MSC条件培养基能够诱导心脏干细胞迁移,这个过程能被VEGFR、CXCR4及c-Met等受体特异阻断剂所阻断,且c-Met可能起主要作用。结论:移植的MSC通过其旁分泌效应激活c-kit阳性的干细胞迁移至心梗部位修复受损的心脏。
OBJECTIVE: To explore whether mesenchymal stem cells transplanted to myocardial infarction can promote the migration of cardiac stem cells to myocardial infarction through their paracrine effect. Methods: The characteristics of mesenchymal stem cells (MSCs) were characterized by flow cytometry and their surface markers were confirmed by multidirectional inducing and differentiation experiments. The characteristics of cardiac stem cell migration were analyzed by Transwell in vitro. The effects of VEGF, HGF, SDF-1α and other receptor-specific blockers on cardiac stem cell migration were observed. Myocardial infarction model was replicated by ligation of the anterior descending coronary artery in vivo. Seven days after myocardial infarction, MSCs were implanted into the infarct and the surrounding area. Seven days after cell transplantation, the c-kit positive stem cells in peripheral blood were analyzed by flow cytometry. The number of c-kit positive stem cells in myocardial infarction was analyzed by immunofluorescence histochemistry. Meanwhile, the expressions of VEGF, HGF, SDF-1α expression, cardiac catheterization was performed after January to measure cardiac function and collagen staining and HE staining to determine infarct size. Results: Transplanted MSC increased the expression of VEGF, HGF and SDF-1α in myocardial infarction sites and mobilized c-kit positive stem cells to migrate to myocardial infarction site. Compared with the control group, the MSC transplantation group significantly reduced the infarct size, significantly increased the blood vessel density and significantly improved left ventricular cardiac function. In vitro migration experiments found that MSC conditioned medium can induce cardiac stem cell migration, this process can be VEGFR, CXCR4 and c-Met and other receptor blockers blocked, and c-Met may play a major role. CONCLUSIONS: Transplanted MSC mobilize c-kit positive stem cells via its paracrine effect to migrate to the infarct site to repair the damaged heart.