脐血源性间充质干细胞与人心肌细胞共培养条件下对心肌细胞凋亡的抑制

Inhibitory effects of co-culture of umbilical cord blood-derived mesenchymal stem cells and human cardiomyocytes on cardiomyocyte apoptosis

背景：脐带血来源的间充质干细胞有多系分化的潜能,其归巢或植入心脏后能够修复心肌组织,但其移植治疗的安全性,以及在与人心肌细胞共培养情况下,能否抑制人心肌细胞凋亡仍有待观察。目的：观察人脐血间充质干细胞与人心肌细胞共培养条件下对人心肌细胞凋亡的抑制作用,以及移植治疗的安全性。方法：人脐血源性间充质干细胞来源于分娩孕妇脐血,经5-氮杂胞苷处理24h向心肌细胞诱导分化。分别取体外培养3~5代细胞以及诱导后细胞,检测其端粒酶活性及肿瘤相关基因RNA水平的表达、染色体核型G带分型、细胞表面抗原表达、裸鼠体内成瘤情况、共培养条件下细胞凋亡情况。结果与结论：脐血源性间充质干细胞经5-氮杂胞苷体外诱导能分化成心肌细胞,诱导前后其端粒酶活性及p53,cyclinA,cdk2,β-actin,c-fos,h-TERT,c-myc等肿瘤相关基因的表达均基本相似;均未发现异常染色体核型;免疫表型无明显变化,CD34呈阴性,CD44及CD90（Thy-1）呈阳性。脐血源性间充质干细胞接种裸鼠体内未见肿瘤生长。与单纯心肌细胞比较,共培养情况下脐血间充质干细胞能够显著抑制心肌细胞的凋亡（P〈0.05）。结果提示人脐血间充质干细胞用于细胞移植治疗安全有效,与心肌细胞共培养时具有明显抑制心肌细胞凋亡的作用。

BACKGROUND：Umbilical cord blood（UCB）-derived mesenchymal stem cells（MSCs） have multi-differentiation potentials,and can repair myocardial tissue following homing or implantation into the heart.However,transplantation safety and whether the transplantation can inhibit apoptosis of human cardiomyocytes under coculture of human cardiomyocytes deserve further investigations.OBJECTIVE：To study the safety and apoptosis inhibition of the UCB-derived MSCs with co-culture on human cardiomyocytes.METHODS：Human UCB-derived MSCs were collected at the time of delivery,and treated with 5-azacytidine for 24 hours and further introduced differentiation into cardiomyocytes.Cells at passages 3-5 and induced cells were obtained to detect the telomerase activation,tumor-related gene RNA levels,chromosome karyotype G typing,cell surface antigen expression,tumor formation in nude mice,and cell apoptosis under coculture.RESULTS AND CONCLUSION：MSCs derived from UCB were differentiated into cardiomyocytes in vitro following induced by 5-azacytidine.Telomerase activity,p53,cyclin A,cdk2,β-actin,c-fos,h-TERT and c-myc expression was similar before and after induction.No abnormal chromosomal karyotypes were observed.Immunophenotype did not significantly change.Cells were negative for CD34,but positive for CD44 and CD90（Thy-1）.There was no tumor formation in nude mice.UCB-derived MSCs significantly inhibited apoptosis of human cardiomyocytes under co-culture conditions compared with cardiomyocytes（P 0.05）.Results have suggested that human UCB-derived MSCs are a valuable safe and effective source of cell-transplantation treatment,and can inhibit the apoptosis of human cardiomyocytes under co-cultured conditions.