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 control group, hypoxia significantly upregulated the expression of miR-21 and impaired CMECs proliferation, migration and tube formation functions. Compared with 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 knockdown of miR-21. Conversely, treatment with miR-21 mimics further enhanced QL induced changes in hypoxic CMECs. Conclusions Our 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.