Figure 4.

AS-IV activates HVUECs to continuously express SUMO1 and improves angiogenesis in a hypoxic environment. SUMO1, ubiquitin, HIF-1α and VEGF protein expression levels were (A) examined via western blotting and (B) normalized to those of β-actin following exposure of HUVECs in the presence or absence of AS-IV treatment to normoxic or hypoxic conditions. (C) Angiogenic potential was measured in simulated angiogenesis experiments in AS-IV-treated (5 ng/ml) and untreated cells in a normoxic or hypoxic environment for 5 days (scale bar, 20 µm). (D) The number of complete vascular lumens and (E) vessel wall thickness were measured. (F) LDH content was measured via ELISA following exposure of HUVECs in the presence or absence of AS-IV treatment to normoxic or hypoxic conditions for 7 days. Data are presented as the mean ± standard deviation. n=3. *P<0.05 vs. control. AS-IV, astrogaloside IV; HUVEC, human umbilical vein endothelial cells; SUMO1, small ubiquitin-related modifier 1; HIF, hypoxia inducible factor; VEGF, vascular endothelial growth factor; LDH, lactate dehydrogenase.