Quan Zhe, Wang Qiang-Li, Zhou Pei, Wang Guo-Dong, Tan Yu-Zhen, Wang Hai-Jie
Department of Anatomy, Histology and Embryology, Shanghai Medical School, Fudan University, Shanghai 200032, P.R. China.
School of Basic Medical Sciences, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China.
Int J Mol Med. 2017 Jun;39(6):1347-1356. doi: 10.3892/ijmm.2017.2950. Epub 2017 Apr 11.
The survival of transplanted stem cells in ischemic tissue is poor. In the present study, the effects of thymosin β4 (Tβ4) on the survival and angiogenesis of endothelial progenitor cells (EPCs) and improvement in cardiac functions after transplantation of Tβ4-treated EPCs in the infarcted myocardium were investigated. EPCs were isolated from bone marrow of adult male rats and incubated in Endothelial Basal Medium-2. Then the cells were treated with Tβ4 at different concentrations (0.05, 0.1 and 0.2 µM), and cells incubated with DMEM were set as controls. MTT assay, Transwell assay and tube formation in Matrigel were used to detect cell viability, migration and angiogenesis, respectively. For examining the protective effect of Tβ4 on EPCs, the cells were also incubated in the condition of hypoxia and serum deprivation. p-Akt expression was also examined using western blot analysis. Rat models of myocardial infarction (MI) were established by ligation of the anterior descending branch of the left coronary artery. At four weeks after intramyocardial injection of Tβ4-treated EPCs, the changes in cardiac functions, size of the scar tissue and density of microvessels were examined by echocardiography, Masson's trichrome staining, immunohistochemistry and fluorescence in situ hybridization (FISH) for the Y-chromosome. Tβ4 enhanced EPC viability, protected the cells from apoptosis in hypoxia and serum deprivation, and promoted the proliferation and migration of the cells and formation of capillary-like structures in the cells. Moreover, Tβ4 increased p-Akt expression in the cells. The cytoprotective and proangiogenic effects of Tβ4 were in a dose-dependent manner. Tβ4-treated EPCs improved cardiac function, enhanced the repair of the infarcted myocardium, and promoted angiogenesis after transplantation in the infarcted myocardium. In conclusion, pretreatment of EPCs with Tβ4 is a novel strategy for the repair of ischemic tissue after transplantation in MI.
移植的干细胞在缺血组织中的存活率较低。在本研究中，研究了胸腺素β4（Tβ4）对内皮祖细胞（EPCs）存活和血管生成的影响，以及经Tβ4处理的EPCs移植到梗死心肌后对心脏功能的改善情况。从成年雄性大鼠的骨髓中分离出EPCs，并在Endothelial Basal Medium-2中培养。然后用不同浓度（0.05、0.1和0.2μM）的Tβ4处理细胞，将用DMEM培养的细胞设为对照组。分别采用MTT法、Transwell法和基质胶中管腔形成实验检测细胞活力、迁移和血管生成。为了检测Tβ4对EPCs的保护作用，细胞也在缺氧和血清剥夺条件下培养。还采用蛋白质印迹分析检测p-Akt表达。通过结扎左冠状动脉前降支建立大鼠心肌梗死（MI）模型。在心肌内注射经Tβ4处理的EPCs四周后，通过超声心动图、Masson三色染色、免疫组织化学和Y染色体荧光原位杂交（FISH）检测心脏功能、瘢痕组织大小和微血管密度的变化。Tβ4增强了EPCs的活力，保护细胞在缺氧和血清剥夺条件下不发生凋亡，并促进细胞增殖、迁移以及细胞中毛细血管样结构的形成。此外，Tβ4增加了细胞中p-Akt的表达。Tβ4的细胞保护和促血管生成作用呈剂量依赖性。经Tβ4处理的EPCs移植到梗死心肌后可改善心脏功能，增强梗死心肌的修复，并促进血管生成。总之，用Tβ4预处理EPCs是MI后移植修复缺血组织的一种新策略。
