Picroside II attenuates hyperhomocysteinemia-induced endothelial injury by reducing inflammation, oxidative stress and cell apoptosis

Picroside II (P-II), one of the main active components of scrophularia extract, which have anti-oxidative, anti-inflammatory effects, but its effect on hyperhomocysteinemia (HHcy) induced endothelial injury remains to be determined. Here, we test whether P-II protects HHcy-induced endothelial dysfunction against oxidative stress, inflammation and cell apoptosis. In vitro study using HUVECs, and in hyperhomocysteinemia mouse models, we found that HHcy decreased endothelial SIRT1 expression and increased LOX-1 expression, subsequently causing reactive oxygen species generation, up-regulation of NADPH oxidase activity and NF-kappa B activation, thereby promoting pro-inflammatory response and cell apoptosis. Blockade of Sirt1 with Ex527 or siRNASIRT1 increased LOX-1 expression, whereas overexpression of SIRT1 decreased LOX-1 expression markedly. P-II treatment significantly increased SIRT1 expression and reduced LOX-1 expression, and protected against endothelial cells from Hcy-induced oxidative injury, inflammation and apoptosis. However, blockade of SIRT1 or overexpression of LOX-1 attenuated the therapeutic effects of P-II. In conclusion, our results suggest that P-II prevents the Hcy induced endothelial damage probably through regulating the SIRT1/LOX-1 signaling pathway.