骨髓间充质干细胞移植对大鼠心肌梗死后细胞凋亡的作用

目的：探讨骨髓间充质干细胞心肌移植对大鼠心肌梗死区细胞凋亡的影响。方法：取大鼠骨髓间充质干细胞进行体外培养、增殖和标记，同时以液氮冷冻左室游离壁建立心肌梗死模型，4周后分别将2×106个细胞悬液或冷D-Hanks液注入心肌梗死区数个不同部位。于移植后1周、2周和4周依次获取心肌梗死区标本。随机于第2周实验组与对照组中各抽取两个标本进行透射电镜检查，凋亡细胞计数，RT-PCR检测所有标本bcl-2 mRNA的表达。结果：部分心肌细胞呈调亡细胞初期形态改变，实验组和对照组调亡指数分别为0.02和0.08。bcl-2 mRNA在术后第1，2及4周的表达水平实验组与对照组相比均增加（P<0.01），且随着时间的推移其表达量两组均呈迅速降低的趋势（P<0.01）。结论：骨髓间充质干细胞心肌移植可促进心肌梗死区Bcl-2蛋白表达，并减轻大鼠心肌梗死后细胞凋亡。

Effect of mesenchymal stem cells transplantation onthe apoptosis after rat myocardial infarction

OBJECTIVE: To investigate the effect of cardiac transplanting of mesenchymal stem cells on the apoptosis after rat myocardial infarction. METHODS: Wistar inbred rats were used to stimulate autograft. Harvested rat mesenchymal stem cells were cultivated, proliferated and labeled in vitro. At the same time, myocardial infarct models were set up using liquid nitrogen to cryoinjury the free wall of the left ventricule. Four weeks later, 2 x 10(6) mesenchymal stem cells or cold D-Hanks liquid were injected into several different points of infarct area. After 1, 2 and 4 weeks, specimens from infarct area were obtained in order. Then the number of apoptosis was counted under scanning electron microscope in every 2 specimens selected at random from the experimental group and the reference group within 2 weeks. The bcl-2 mRNA expression of all rats was assayed by RT-PCR. RESULTS: The observation of transmission by electron microscope showed that part of the myocardial cells became apoptosis in the initial stage in ultramicrostructure. Apoptosis ratio was 0.02 and 0.08 in the experimental group and the reference group respectively, which demonstrated that mesenchymal stem cells could relieve apoptosis after rat myocardial infarctation. The levels of bcl-2 mRNA expression in 1, 2, and 4 weeks were all obviously promoted in the experimental 1.2. group (3.235 +/- 0.126, 1.152 +/- 0.021, 0.798 +/- 0.016) than those in the reference group (2. 695 +/- 0.084, 0.537+/-0.022, 0.579+/-0.019) (P < 0.01), and quickly decreased with time. CONCLUSION: Mesenchymal stem cells transplantation can promote the expression of bcl-2 mRNA in the infarct area and relieve apoptosis after rat myocardial infarction.