Protective effects of salvianolic acid B against hydrogen peroxide­induced apoptosis of human umbilical vein endothelial cells and underlying mechanisms.

Salvianolic acid B (Sal B) is a water­soluble active component of Danshen and has anti­atherosclerotic effects. The present study aimed to evaluate the cytoprotective effects of Sal B against hydrogen peroxide (H2O2)­induced oxidative stress damage in human umbilical vein endothelial cells (HUVECs) and investigate the underlying mechanisms. It was revealed that Sal B protected the cells from H2O2­induced damage, as indicated by MTT results showing enhanced cell viability and by flow cytometric analysis showing reduced apoptosis of cells challenged with H2O2. Furthermore, as an underlying mechanism, the enhancement of autophagy was indicated to be accountable for the decrease in apoptosis, as Sal B caused the upregulation of light chain 3­â…¡ and Beclin­1, and downregulation of p62 under H2O2­induced oxidative stress. Finally, Sal B increased the phosphorylation of AMP kinase (AMPK) and decreased the phosphorylation of mammalian target of rapamycin (mTOR), but had no effect on the phosphorylation of AKT. In conclusion, the present study revealed that Sal B protects HUVECs from oxidative stress, at least partially by promoting autophagy via activation of the AMPK pathway and downregulation of the mTOR pathway.