摘要目的 探讨人脐带间充质干细胞(MSCs)在体外向心肌细胞分化的能力及移植后对急性心肌梗死大鼠心功能恢复的影响.方法 胶原酶胰酶消化法分离脐带MSCs.取第4-6代脐带干细胞,采用5-氮胞苷诱导,免疫组织化学和免疫荧光法对诱导后细胞进行鉴定.建立大鼠心肌梗死模型,并按完全随机法将其分为2组(n=10):细胞移植组和空白对照组.将培养脐带MSCs移植到大鼠梗死心肌周围,4周后,免疫荧光法鉴定移植细胞,并超声检测心功能改变.结果 体外诱导后,细胞的形态不断发生变化,诱导后的细胞表达心肌特异性α-肌动蛋白、肌球蛋白和肌钙蛋白T,阳性率在50%以上.细胞移植4周后,脐带MSCs在缺血心肌内存活并分化为心肌样细胞,心功能检测显示脐带MSCs移植组大鼠在移植后4周的左心室射血分数[(68.4±15.2)%]比对照组大鼠明显增加[(53.2±13.4)%,P＜0.05].结论 人脐带MSCs能够在体内外分化为心肌样细胞,并能促进心脏功能的恢复.

abstractsObjective To evaluate the capability of the cardiomyogenic differentiation of human umbilical cord (UC) mesenchymal stem cells (MSCs) in vitro and therapeutic effects on heart function recovery in rats with acute myocardial infarction (MI) post-transplantation. Methods The UC-MSCs were isolated by collagenase and trypsogen digestion, and the 4th to 6th passages of UC-MSCs were collected for 5- azacytidine induction, then identified by imrnunohistochemistry and immunofluorescence. MI models were established in rats and randomly divided into 2 groups (n=10 each): cell transplantation group (received transplantation of cultured UC-MSCs to around infarcted myocardium) and control group. Four weeks later,immunofluorescence was performed to identified the transplanted stem cells, and changes in cardiac function was detected by ultrasound. Results There was a consistent change in morphology of UC- MSCs after induction in vitro. Positive rates of specific α- cardiac actin, myosin and Troponin T after 5- azacytidine induction were over 50%. Four weeks after cell transplantation, the transplanted umbilical cord mesenchymal stem cells survived in infarcted myocardium and differentiated into cardiomyocyte-like cells. Cardiac function test showed greater level of left ventricular ejection fraction (LVEF) in UC-MSCs group four weeks after transplantation [ (68.4± 15.2)% ] compared with control group [ (53.2± 13.4)%, P＜0.05]. Conclusion Human umbilical cord mesenchymal stem cells may differentiate into cardiomyocyte-like cells in vitro and may contribute to recovery of cardiac function.