过刊浏览

急性心肌缺血对骨髓Nkx2-5+ 心脏祖细胞的动员作用

董红燕, 徐志伟, 张中明, 于红丽, 徐夏红

徐州医学院1 神经生物学研究中心； 附属医院胸心外科，徐州221002

摘要

骨髓源性Nkx2-5+ 心脏祖细胞(bone marrow-derived Nkx2-5+ cardiac progenitor cells)具有高度特异性分化为心肌细胞的潜 能，在病理状态下可能参与内源性心肌修复。但在器官缺血、特别在急性心肌缺血病理状态下，该细胞如何被动员的机制 尚不清楚。 本研究在观察Nkx2-5+ 心脏祖细胞在骨髓中分布特征的基础上，分析急性心肌缺血对骨髓源性Nkx2-5+ 心脏祖细胞的动 员作用，探讨其细胞动员的可能机制。分别建立小鼠急性心肌缺血及脑、后肢急性缺血动物模型。采用纳米金- 银免疫标 记透射电镜、免疫荧光标记及分子生物学等检测方法，观察骨髓Nkx2-5+ 心肌祖细胞的定位及其形态学特征；检测急性心肌 缺血后外周血Nkx2-5+ 细胞比例变化、缺血不同时段骨髓及外周血中Nkx2-5 蛋白表达的变化；比较不同器官缺血对Nkx2-5+ 心脏 祖细胞的动员作用；应用SDF-1/CXCR4 通路特异性阻断剂AMD3100，分析SDF-1 在急性心肌缺血后对Nkx2-5+ 心脏祖细胞 动员作用的影响。结果显示：Nkx2-5+ 心脏祖细胞呈散在分布于骨髓血窦旁。与对照组相比，急性心肌缺血后，外周血Nkx2-5+ 心脏祖细胞比例显著增加(P<0.01)。心肌缺血早期(1 d)，外周血Nkx2-5 蛋白表达显著增加(P<0.01)，并可持续7 d；而此间， 骨髓中Nkx2-5 蛋白表达立即升高，随后则降低。应用AMD3100 阻断剂后，心肌缺血组外周血Nkx2-5 蛋白表达受到明显抑 制(P<0.05)。脑、后肢缺血后，外周血Nkx2-5 蛋白表达显著少于急性心肌缺血组(P<0.01)，而与对照组相比无显著差异。上述结果提示，生理状态下，骨髓中存在Nkx2-5+ 心脏祖细胞亚群；急性心肌缺血对骨髓Nkx2-5+ 心脏祖细胞具有显著的动员 作用，且该动员作用具有显著的器官特异性，SDF-1/CXCR4 通路在该动员作用中发挥了重要的趋化作用。

关键词： 心脏祖细胞; 骨髓; Nk x 2 -5 ; 动员; 心肌缺血

分类号：R542.2

Mobilization of bone marrow-derived Nkx2-5+ cardiac progenitor cells undercondition of acute myocardial ischemia

DONG Hong-Yan, XU Zhi-Wei, ZHANG Zhong-Ming, YU Hong-Li, XU Xia-Hong

Center of Neurobiological Research； Department of Cardiothoracic Surgery of Affiliated Hospital, Xuzhou Medical College, Xuzhou 221002, China

Abstract

The present study aimed to observe the morphological distribution of bone marrow (BM)-derived Nkx2-5+ cardiac progenitor cells (CPCs) in bone marrow niche and evaluate the effect of acute myocardial ischemia (AMI) on the mobilizion of BM-derived Nkx2-5+ CPCs. Animal models of BALB/c mouse AMI, cerebral and hind-limb ischemia were established. Nanogold labeling method, immunofluorescence and Western blot were used to identify the distribution of BM-derived Nkx2-5+ CPCs and the expressions of Nkx2-5 protein in peripheral blood and BM after AMI. Meanwhile, in different ischemia organ models and after AMD3100 (SDF-1/ CXCR4 antagonist) pretreatment in AMI model, Nkx2-5 protein expressions in peripheral blood were also assayed. Nkx2-5+ CPCs were found to locate in cavitas medullaris. The percentage of Nkx2-5+ CPCs in blood increased immediately after AMI. Nkx2-5 protein expression in peripheral blood was also upregulated at the timepoint of 24 h post-AMI (P<0.01) and kept stable without further enhancement from day 1 to day 7 post-AMI. In BM, Nkx2-5 protein expression was upregulated immediately after AMI and downregulated afterwards (P<0.01). After AMD3100 pretreatment in AMI group, Nkx2-5 protein expression was significantly inhibited in peripheral blood (P<0.05). In cerebral and hind-limb ischemia models, Nkx2-5 protein expressions were significantly lower than that in AMI group (P<0.01), but with no significant difference to control group. These results suggest that Nkx2-5+ CPCs are physiologically resident in BM and AMI initiates mobilization of BM-derived Nkx2-5+ CPCs in a predominant organ-specific manner. In the procedure of mobilization, SDF-1 may play a critical role in a chemoattracted manner.

Key words: cardiac progenitor cells; bone marrow; Nkx2-5; mobilization; myocardial ischemia

收稿日期：2008-12-03　　录用日期：2009-02-19

通讯作者：张中明　　E-mail: zhang_zhongming@yahoo.com.cn

引用本文：

董红燕, 徐志伟, 张中明, 于红丽, 徐夏红. 急性心肌缺血对骨髓Nkx2-5+ 心脏祖细胞的动员作用[J]. 生理学报 2009; 61 (2): 185-193.

DONG Hong-Yan, XU Zhi-Wei, ZHANG Zhong-Ming, YU Hong-Li, XU Xia-Hong. Mobilization of bone marrow-derived Nkx2-5+ cardiac progenitor cells undercondition of acute myocardial ischemia. Acta Physiol Sin 2009; 61 (2): 185-193 (in Chinese with English abstract).