脐血间质干细胞移植后梗死心肌细胞的凋亡及意义

目的探讨脐血间质干细胞移植对梗死心肌残存心肌细胞凋亡的影响。方法无菌条件下采集成年杂种妊娠犬脐血,体外分离、纯化、培养、扩增脐血间质干细胞,经5-氮杂胞苷(5-aza)体外诱导向肌源性细胞分化,DAPI荧光标记,经左冠状动脉前降支灌注移植入成年杂种犬急性心肌梗死模型区域,2、4、8周取心肌标本,采用HE染色及TUNEL法检测犬心肌梗死模型中脐血间质干细胞移植后心肌细胞的凋亡情况。结果免疫组化法检测结果表明,培养的细胞为脐血间质干细胞,在5-aza诱导作用下可向肌源性细胞定向分化,2、4、8周后在移植区域观察到带荧光的心肌纤维和细胞核,排列方向与残留心肌组织基本一致,荧光标记的肌纤维相互连接。经TUNEL法检测可见在脐血间质干细胞移植组和对照组心肌梗死区域均有凋亡的心肌细胞分布,但移植组凋亡细胞明显低于非移植组;HE染色有相似的阳性率,阳性细胞多具有凋亡的形态特征。结论脐血间质干细胞移植梗死心肌除能形成心肌再生外,尚能减少心肌梗死后梗死区域的心肌细胞凋亡,达到延缓心室重构的目的。应用TUNEL法检测心肌细胞凋亡有较强的实用性。

Detection and significance of myocardial apoptosis after transplantation by umbilical cord blood stem cells in myocardial infarction area

Objective To examine the effects of umbilical cord blood stem cells transplantation on myocardial apoptosis in myocardial infarction area. Methods The umbilical cord blood was collected from pregnant mongrel under aseptic condition.The umbilical cord blood stem cells were isolated,purified,cultured,proliferated and differentiated into the muscular-germ cells by 5-azacytidine(5-aza) in vitro.These cells were labelled with fluorescence by using DAPI,and were transplanted into the adult mongrel's acute myocardial infarction area from the left anterior descending branch.At the 2nd,4th and 8th week,the cardiac muscle specimen was collected.Myocardial apoptosis after umbilical cord blood stem cells transplantion into the myocardial infarction model mongrel was examined by using HE staining and TUNEL method. Results The immunohistochemical examination indicated that the cultured cells were umbilical cord blood stem cells,which were isolated and differentiated into muscular-germ cells under 5-aza induction.After 2,4,8 weeks,fluorescence-marked myocardial fibers and cell nucleus were observed in the transplantation area,their orientation was consistent with the residual cardiac muscular cells,and fluorescence-marked muscular fibers were mutually connected.It was revealed by TUNEL examination that myocardial apoptosis was observed in both of the myocardial infarction area in umbilical cord blood stem cells transplantation group and control group.However,the amount of the myocardial apoptosis in transplantation group was much less than that in control group.HE staining revealed the similar positive rate,and most HE staining-positive cells exhibited the same characteristics of apoptosis. Conclusion Umbilical cord blood stem cells transplantation may not only be able to form myocardial cells regeneration,but also reduce cardiac muscular cell apoptosis in the infarction area after myocardial infarction,which can slow down the ventricle remodeling.The TUNEL method may paly a role in the detection of myocardial apoptosis.