HIF-1α Was a Key Regulator to Improve hBMSCs to Secrete Vascular Endothelial Cytokine with Astragaloside in Hypoxia

This study aimed to assess the combined therapeutic efficacies with gene therapy and stem cell treatment and herb on the differentiation of hBMSCs into vascular endothelial cells under hypoxia condition. The third passage of hBMSCs were randomly divided into four groups, including control group (hBMSCs transfected with empty vectors), VEGF group (VEGF gene transfected to hBMSCs), AST group (cultured with AST), and VEGF + AST group (the intervention of VEGF group plus AST group). Each group was cultured at 37°C and 5% O2 for 2 weeks. Cell morphology was observed by inverted phase and were crowded and arranged irregularly in the control group and AST group, showing a fiber-like growth, while those in the VEGF group and VEGF plus AST group were mostly triangular or polygonal, exhibiting a colony-like growth, contrast microscope. CD31 was negative in the control group and AST group, while CD105 was positive in both groups, tested by flow cytometry assay. The positive rate of CD31 was significantly higher in the VEGF group than it in the VEGP + AST, and the positive rate of CD105 was lower in the VEGF group than it in the VEGF + AST group. The levels of VEGF and endothelial nitric oxide synthase (eNOS) by ELISA and the expression of endothelin and prostacyclin by west blot (WB) and RT-PCR were significantly higher in VEGF group and AST group and VEGF plus AST group, compared with control group. Further, the expression of endothelin and vWF and VEGFR-2 was highest in the VEGP + AST group and the expression of prostacyclin was lowest in VEGF group. AST can promote the secretion of VEGF from the differentiation of hBMSCs induced by VEGF gene transfected to hBMSCs by HIF-1α under hypoxia.