人脐带间充质干细胞经5-氮胞苷诱导后心肌特异性肌钙蛋白I的表达

背景：人脐带间充质干细胞具有多向分化潜能，经诱导后是否可向心肌细胞分化？目前的报道尚不多。目的：观察人脐带间充质干细胞经5-氮胞苷诱导分化后肌钙蛋白I的表达情况。方法：取第2代人脐带间充质干细胞标本，经消化、离心、沉淀后，分为7份，制成细胞悬液，调整细胞浓度为2×10^7L^-1，分别加入浓度为80，40，20，10，5，2．5，0μmol／L5-氮胞苷于同样条件继续培养，作用24h后除去，继续培养4周。结果与结论：①人脐带间充质干细胞经5-氮胞苷处理24h之后，各组细胞都会出现部分死亡，失去典型的梭形形态，成为棍状或者柱状，40，80μmol／L组细胞形态变化明显。②免疫组化染色显示5，10，20，40，80μmol／L组诱导后2周心肌特异性肌钙蛋白I表达呈阳性，对照组与2．5μmol／L组心肌特异性肌钙蛋白I表达为阴性。选取5个高倍视野进行细胞计数，80，40，20，10μmol／L组间心肌样细胞的转化率差异无显著性意义，均明显高于5μmol／L组（P〈0．05）。⑨超微结构观察显示经5-氮胞苷诱导后4周时部分人脐带间充质干细胞内可见典型的肌小节及心房颗粒。而未经5-氮胞苷诱导的对照组无以上改变。结果提示经5-氮胞苷诱导后人脐带间充质干细胞能够向心肌样细胞转化。

Cardiac troponin I expression in human umbilical cord mesenchymal stem cells after 5-azacytidine induction in vitro

BACKGROUND： Human umbilical cord mesenchymal stem cells possess multi-differentiation potential. There are few studiesdescribing whether human umbilical cord mesenchymal stem cells can be induced to differentiate into cardiornyocytes. OBJECTIVE： To investigate cardiac troponin I expression in human umbilical cord mesenchymal stem cells after 5-azacytidine induction in vitro. METHODS： Passage 2 human umbilical cord mesenchymal stem cells were digested, centrifuged and deposited. Cell suspension was prepared and cell concentration was adjusted to be 2×10^7/L. Then cells were cultured for 24 hours after addition of various concentrations of 5-azacytidine （80, 40, 20, 10, 5, 2.5, 0 μmol/L）. After removal of 5-azacytidine, cells were cultured for another 4 weeks. RESULTS AND CONCLUSION： After treatment with 5-azacytidine for 24 hours, some cells died in each group, and typical fusiform appearance turned into stick-like or column-like appearance, especially in the 40 and 80 μmol/L 5-azacytidine groups. Immunohistochemical staining results showed that cardiac troponin I expression was detected in human umbilical cord mesenchymal stem cells in 5, 10, 20, 40, 80 μmol/L 5-azacytidine groups after induction for 2 weeks, but it was not detected in the control and 2.5 μmol/L 5-azacytidine groups. Five high-fold fields were selected for cell counting. The number of cardiomyocytes was not significantly different between 80, 40, 20, 10 μmol/L 5-azacytidine groups, but it was significantly higher compared to that in the 5 μmol/L 5-azacytidine group. After 5-azacytidine treatment for 4 weeks, typical sarcomeres and cardiac atrium particles were observed in some human umbilical cord mesenchymal stem cells. Such changes were not observed in the control group in which 5-azacytidine induction was not used. These findings suggest that human umbilical cord mesenchymal stem cells were induced to cardiomyocyte-like cells by 5-azacytidine.