miR-126及VEGF在大鼠心肌梗死交界区表达的动态变化

目的 观察大鼠心肌梗死(MI)后MI交界区微小RNA-126(miR-126)及血管内皮生长因子（VEGF）表达的动态表达变化，初步探讨miR-126及VEGF对缺血局部血管新生的影响。方法 雄性SD大鼠结扎冠状动脉左前降支建立急性心肌梗死模型组(AMI组)，另设假手术对照组(Sham组)，每组30只。于术后7 d、14 d和28 d分别处死10只大鼠，进行MI面积百分比测定，实时荧光定量PCR法检测心梗交界区miR-126、VEGF mRNA表达水平，免疫组织化学方法检测各组大鼠MI交界区VEGF蛋白的表达。结果 Sham组术后7 d、14 d和28 d心肌组织 miR-126 mRNA和VEGF mRNA的表达均无明显区别，AMI组术后7 d、14 d和28 d，MI交界区mir-126 mRNA表达与相应的Sham组相比，均有不同程度的下降(P<0.01)，而VEGF mRNA的表达则均有不同程度的增高(P<0.01)；在AMI组,随着MI时间的延长，miR-126和VEGF mRNA的表达均逐渐升高,且在AMI 14 d达到高峰（P<0.05）。VEGF 的蛋白表达情况与其基因表达基本一致。结论 大鼠MI后VEGF mRNA及其蛋白的表达明显升高的同时伴随miR-126基因表达的降低，随着缺血时间延长，miR-126 mRNA表达有所恢复。

Changes of miR-126 and VEGF expression levels in myocardium post-acute myocardial infarction in rats

AIM To investigate the changes of miR-126 and VEGF expression levels in myocardium post-acute myocardial infarction (AMI) in rats and to explore the effect of miR-126 and VEGF on the angiogenesis in the junctional zone of infarcted region post-AMI. METHODS The left coronary arteries of male rats were ligated to make the models of AMI (AMI group, n=30). The sham-operated group (n=30) was established. VEGF in the marginal zone of infarcted region was detected by immunohistochemical staining and the expression levels of miR-126 and VEGF mRNA were determined by real-time RT-PCR at 7, 14 and 28 days after operation. RESULTS Compared with those in sham-operated group, the expression levels of miR-126 at the 7th, 14th and 28th day after AMI obviously decreased (P<0.01), whereas expressions of VEGF mRNA increased to some extent in the model group (P<0.01). Expression levels of miR-126 and VEGF mRNA show no significant change in the sham group after the 7th, 14th and 28th days. But the expression levels of miR-126 and VEGF mRNA increased over time in the MI group. Peaks of miR-126 and VEGF mRNA expression emerged at day 14 post-AMI and were then downregulated. Expression levels of VEGF protein and VEGF mRNA were basically the same. CONCLUSION Gene expressions of miR-126 decrease, whereas VEGF mRNA and protein increase post-AMI in rats. miR-126 mRNA recovers to some extent after infarction for some time.