Figure 4.

Effect of Ca²⁺- and phosphatidylinositol 3-kinase (PI3K)/serine/threonine kinase Akt-dependent signaling pathway on the astragaloside IV (AS-IV)-induced phosphorylation of endothelial nitric oxide synthase (p-eNOS) in endothelial cells. Human umbilical vein endothelial cells (HUVECs) were preincubated with or without N^G-monomethyl-L-arginine (L-NMMA, 1 mmol/L), LY294002 (10 µmol/L), or ethylene glycol tetraacetic acid (EGTA, 500 nmol/L) for 1 h and then incubated with AS-IV (30 µmol/L) for an additional 40 min. Cell lysates were immunoblotted with the antibodies against p-eNOS at Ser1177 or eNOS. (A) Representative western blot of p-eNOS in HUVECs. (B) Bar graph shows the relative optical density values for p-eNOS in HUVECs. Data were expressed as the ratio of p-eNOS to corresponding eNOS. ⁣^∗p < 0.05 compared with the control group; †p < 0.05 compared with HUVECs exposed to AS-IV alone.