Pretreatment with Astragaloside IV protects human umbilical vein endothelial cells from hydrogen peroxide induced oxidative stress and cell dysfunction via inhibiting eNOS uncoupling and NADPH oxidase – ROS – NF-κB pathway

Endothelial cell injury caused by reactive oxygen species (ROS) plays a critical role in the pathogenesis of cardiovascular disorders. Astragaloside IV (AsIV) possesses potent antioxidant properties against oxidative stress through undefined mechanism(s). We sought to investigate whether AsIV protects human umbilical vein endothelial cells (HUVECs) from hydrogen peroxide (H2O2) induced oxidative stress focusing on eNOS uncoupling and the NADPH oxidase – ROS – NF-κB pathway. Compared with HUVECs incubated with H2O2 alone, pretreatment with AsIV significantly increased the viability of HUVECs, which was accompanied with apparent increase in nitric oxide (NO) production and decrease in intracellular superoxide anion production. Furthermore, pretreatment with AsIV increased endothelial nitric oxide synthase (eNOS) dimer/monomer ratio and its critical cofactor tetrahydrobiopterin (BH4) content, decreased Nox4 protein expression (the most abundant Nox isoform in HUVECs), inhibited translocation of NF-κB p65 sub...