MiR-26a promotes angiogenesis in rats with cerebral ischemia through PI3K/Akt pathway / 国际脑血管病杂志

ABSTRACT

Objective:To investigate the effect of miR-26a mediated phosphatidylinositol-3 kinase (PI3K)/protein kinase B (AKT) signaling pathway on angiogenesis in rats with cerebral ischemia.Methods:A total of 100 male SD rats were divided into sham operation group, model group, miR-NC group, and miR-26a group according to the random number table method. The miR-NC group and the miR-26a group were injected with 5 μl miR-26a simulant negative control and miR-26a simulant into the lateral ventricle respectively. The sham operation group and the model group were injected with the same amount of normal saline respectively. The middle cerebral artery occlusion model was induced by the modified intraluminal suture method. In the sham operation group, the thread was only inserted without ligation. Five rats in each group were injected intraperitoneally with 5-bromodeoxyuridine (BrdU) daily for 7 days. Rat brain microvascular endothelial cells (BMECs) cultured and transfected in vitro were divided into control group, oxygen glucose deprivation (OGD) group, miR-NC group, and miR-26a group. The dual luciferase experiment verified the regulatory effect of miR-26a on the phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Longa score was used to detecte the neurological damage of rats. The volume of cerebral infarction was measured by triphenyltetrazolium chloride (TTC) staining. The methyl thiazolyl tetrazolium (MTT) staining, annexin Ⅴ fluorescein isothiocyanate/propidium iodide double staining and tubule formation experiment were used to detect the proliferation, apoptosis and angiogenesis of BMECs, respectively. Real-time fluorescence quantitative reverse transcription polymerase chain reaction was used to detect the miR-26a expression of ischemic brain tissue and BMECs. Immunofluorescence double labeling method (BrdU/von Willebrand factor [vWF]) was used to detect the proliferation of rat vascular endothelial cells. Western blot analysis was used to detect the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), angiopoietin-2 (Ang-2), PTEN, PI3K and Akt protein in ischemic brain tissue.Results:Bioinformatics and dual luciferase experiments verified the targeted regulation of PTEN by miR-26a. Compared with the sham operation group, the expression of miR-26a, VEGF, bFGF, Ang-2, PI3K, AKT and the number of BrdU + /VWF + cells in ischemic brain tissue in the model group and miR-NC group increased, while the expression of PTEN decreased (all P<0.05). Compared with the model group, the effect of various indexes in the miR-26a group was more significant (all P<0.05). Compared with the control group, the proliferation and angiogenesis of BMECs in the OGD group and the miR-NC group were significantly increased, and the apoptosis was significantly reduced (all P<0.05). Compared with the OGD group, the effect of various indexes in the miR-26a group was more significant (all P<0.05). Conclusion:miR-26a can mediate the targeted inhibition of PTEN expression, up-regulate angiogenesis related factors (VEGF, bFGF and Ang-2), and promote vascular endothelial cell proliferation and angiogenesis in rats with cerebral infarction by activating PI3K/Akt signaling pathway.