过表达HGF增强脐带间充质干细胞减少缺血性心肌病恶性室性心律失常发生的机制研究

The survival and reproduction potential of bone marrow mesenchymal stem cells (BMMSCs) are nonetheless impaired, thus limiting their therapeutic efficiency in patients with ischemic heart disease and ventricular arrhythmias (VA). So, to find the novel stem cells with strong survival and reproduction potential and methods with improving local microenvironment to increase cells survival rate and reproduction ability are very beneficial for ischemic heart disease and VA therapy. On the base of establishing the model of myocardial infarction in severe combined immunodeficiency disease (SCID) mice, and verifying the transplantation of umbilical cord mesenchymal stem cells (UCMSCs) with overexpression of hepatocyte growth factor (HGF) could increase the UCMSCs survival, promote vessel generation and Cx43 gene expression, and reduce the occurrence of malignant VA. We are going to design in vitro experiments, to investigate that survival rate of UCMSCs and HGF-UCMSCs in hypoxia environment, and to investigate that hypoxic- conditioned medium (hy-CdM) protection function and mechanism for neonatal mice cardiomyocytes (NMCs) in hypoxia environment and related mechanism. We are also going to design in vivo experiments, to investigate that the effect of UCMSCs with overexpression of HGF transplantation on cardiac function, myocardium apoptosis, myocardium fibroblast, and nerve and vessel generation. It is to elucidate that the mechanism of UCMSCs with overexpression of HGF transplantation to improve arrhythmia substrate and reduce the occurrence of malignant VA in mice with ischemic heart disease.

骨髓间充质干细胞（BMMSCs）移植后在体内生存时间短，增殖能力弱是治疗缺血性心肌病效果欠佳的主要原因。因此寻找移植后在体内生存时间长、增殖能力强的新型干细胞或能改善局部微环境促进细胞增殖的因子，将提高干细胞移植治疗缺血性心肌病恶性室性心律失常的效果。本研究在成功建立免疫缺陷小鼠心肌梗死模型基础上，发现过表达肝细胞生长因子（HGF）的脐带间充质干细胞（UCMSCs）移植治疗，可提高UCMSCs成活率、促进血管增生与Cx43基因表达、减少恶性室性心律失常发生。拟设计体外实验，研究UCMSCs与HGF-UCMSCs在缺氧条件下的生存率，及其条件培养液对缺氧环境下小鼠心肌细胞的保护作用及其机制；拟设计体内实验，研究HGF-UCMSCs移植对缺血性心肌病心功能、心肌细胞凋亡、心肌纤维化、血管神经再生与室性心律失常发生等影响，通过体内外实验研究，阐明过表达HGF的UCMSCs减少室性心律失常发生机制

骨髓间充质干细胞（BMMSCs）移植后在体内生存时间短，增殖能力弱是治疗缺血性心肌病效果欠佳的主要原因。因此寻找移植后在体内生存时间长、增殖能力强的新型干细胞或能改善局部微环境促进细胞增殖的因子，将提高干细胞移植治疗缺血性心肌病的效果。本研究结果发现过表达肝细胞生长因子（HGF）的脐带间充质干细胞（UCMSCs）（HGF-UC-MSCs）增强UC-MSCs在缺氧环境中的生存能力；HGF-UC-MSCS的缺氧条件培养基可阻止NCM细胞凋亡；缺氧环境中，HGF-UC-MSCs的上清液可促进Akt磷酸化，降低Bax/Bcl-2比例，减少心肌细胞凋亡；缺氧环境中，HGF-UC-MSCs组上清液较UC-MSCs组上清液中HGF, EGF, bFGF与VEGF含量高；HGF-UC-MSCs移植治疗可以缩小心肌梗死面积，改善心功能；在心肌梗死模型中，HGF-UC-MSCs移植可以增强心肌保护作用，减少心肌纤维化；在缺血环境下，HGF-UC-MSCs生存能力增强；HGF-UC-MSCs移植治疗可以减少心肌细胞凋亡，增加血管再生。本研究成果将对缺血性心肌病的治疗提高新思路。