Electro-acupuncture Promotes Angiogenesis via Exosomal miR-210 in the Hypoxia-induced HUVECs Mediated HIF-1α/VEGF/Notch 1 Signal Pathway

Acupuncture has been wildly applied for cerebral ischemia treatment in China for thousands of years, while the specific mechanism remains uncertain. Recently, many studies have shown that acupuncture promotes angiogenesis after ischemia occurs. Here, we examined the effect of electro-acupuncture (EA) exosomes on angiogenesis in hypoxia-induced human umbilical vein endothelial cells (HUVECs).To investigate whether EA exosomal miR-210 promotes angiogenesis in the hypoxiainduced HUVECs via the HIF-1α/VEGF/Notch 1 signal pathway.The middle cerebral artery occlusion (MCAO) model was established and treated with EA therapy. Then, exosomes were identified and isolated from rats' plasma in the MCAO+EA group by transmission electron microscopy (TEM), surface markers expressions, and PKH26 reagent. MiR- 210 mimic, miR-210 inhibitor, and HIF-1α were transfected. Flow cytometry, CCK-8 assay, and Transwell assay were conducted to assess the migration, apoptosis, and proliferation of each group of cells. Western blot and quantitative PCR were performed to detect the CD34, HIF-1α, VEGF, Notch 1, and miR-210 expression levels in each group.MiR-210 was significantly upregulated in exosomes of the MCAO plasma, and further enhanced by EA therapy. EA-EXOs and miR-210 mimic inhibited cell apoptosis, promoted cell proliferation and cell migration in hypoxia-induced HUVECs. However, the miR-210 inhibitor reversed the proliferation and migration number induced by EA-EXOs. Besides, EA-EXOs and miR- 210 mimic further enhanced those HIF-1α, VEGF, and Notch 1 levels compared to the hypoxia treatment only. Silencing HIF-1α or miR-210 reversed the high expressions of those three angiogenic factors induced by hypoxia and EA-EXO. qPCR showed similar trends with their relative mRNAs. To analyze these associations quantificationally, Spearman's rank correlation coefficient was calculated. As revealed by results, the expression of proteins and mRNA were highly correlative with each other.These results indicated that EA-EXO miR-210 promotes angiogenesis in hypoxia conditions via HIF-1α/VEGF/Notch 1 signal pathway.