Fermented Chinese Formula Shuan-Tong-Ling Protects Brain Microvascular Endothelial Cells against Oxidative Stress Injury

Fermented Chinese formula Shuan-Tong-Ling (STL), composed of fourteen medicinal herbs, was an experiential formula by Dr. Zhigang Mei for treating vascular encephalopathy, but the underlying mechanisms remained unknown. In this study, we aimed to investigate the protective effects of fermented STL on hydrogen peroxide- (H2O2-) induced injury in rat brain microvascular endothelial cells (BMECs) and the possible mechanisms. Cultured BMECs were treated with H2O2, STL, or nicotinamide (NAM, a SIRT1 inhibitor). Then, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was employed to detect cell proliferation and senescence-associated beta-galactosidase (SA-β-gal) was used to examine cell senescence. Cell nuclei were observed by 4',6-diamidino-2-phenylindole. Additionally, changes in reactive oxygen species (ROS), superoxide dismutase (SOD), and glutathione (GSH) levels were measured. Expression of SIRT1, p21, and PGC-1α was determined by western blot. Cell proliferation significantly increased with STL treatment in a dose-dependent manner. H2O2 treatment could intensify cell senescence and nuclei splitting or pyknosis. With STL treatment, the reduced ROS level was accompanied by increased SOD and GSH activity. Further assays showed upregulation of SIRT1 and PGC-1α and downregulation of p21 after STL treatment. The results revealed that STL could protect BMECs against oxidative stress injury at least partially through the SIRT1 pathway.