Qiliqiangxin Prescription Promotes Angiogenesis of Hypoxic Primary Rat Cardiac Microvascular Endothelial Cells via Regulating miR-21 Signaling

Background and Objective: Angiogenesis is the most important repair process of tissues subjected to ischemic injury. The present study aims to investigate whether the pro-angiogenic effect of Qiliqiangxin prescription (QL) is mediated through miR-21 signaling. Methods: Cardiac microvascular endothelial cells (CMECs) were isolated and cultured from 2-3 weeks old SD rats by the method of planting myocardium tissues. The purity was identified by CD31 immunofluorescence staining. CMECs were then cultured under 1% O2 hypoxia or normoxia condition for 24h in the presence or absence of QL pretreatment (QL, 0.5mg/ml, 24h). The mimics and inhibitors of miR-21 were transfected into CMECs. miR-21, HIF-1α, and VEGF expressions of CMECs were then detected by qRT-PCR and/or Western blot. The proliferation, migration, and tube formation functions of CMECs were assessed using the BrdU assay, wound healing test, and tube formation assay, respectively. Results: The results showed that compared with the control group, hypoxia significantly upregulated the expression of miR-21 and impaired CMECs proliferation, migration, and tube formation functions. Compared with the hypoxia group, QL further upregulated miR-21, HIF-1α, and VEGF expressions, and improved cell proliferation, migration, and tube formation of hypoxic CMECs. These effects of QL were abolished by a knockdown of miR-21. Conversely, treatment with miR-21 mimics further enhanced QL induced changes in hypoxic CMECs. Conclusion: Results indicate that the pro-angiogenesis effects of QL on hypoxic CMECs are mediated by activating miR-21 and its downstream HIF-1α/VEGF pathway possibly.