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.