Regulation Of Salvia Miltiorrhiza On Signal Transduction Of Endothelial Cells

Elucidating the active substances, compositions and action mechanisms of modern Chinese medicines is a key problem to be solved for their modernization. In this work, Salvia Miltiorrhiza Bunge, a traditional Chinese medicinal herb, was selected as a model to investigate its protective effects on the cultured Human umbilical vein endothelial cells (HUVECs) with much focus on the adhesion and barrier adjustment that are vital to the functions of endothelial cells. Signal transduction of the involved signal molecules was also studied to explore the mechanisms of Salvia Miltiorrhiza in the cellular and molecular levels.We investigated the effect of extract of Salvia Miltiorrhiza (ESM) on the adhesion of HL-60 cells to TNF-α-induced HUVECs by rose Bengal staining assay, and that of ESM on TNF-α-induced expression of adhesion molecules and activation of nuclear factor-kappa B (NF-κB) in HUVECs by ELISA, Western blotting and immunocytochemistry assays. The results showed that ESM significantly inhibited the up-regulation of expression of the adhesion molecules in TNF-α-induced HUVECs; reduced the degradation of inhibitor of NF-κB (IκB) and subsequently blocked the activation of NF-κB, suggesting that the blockade of NF-κB activation of ESM be implicated in its regulation of adhesion molecules in HUVECs.The effects of ESM and its major active ingredients DSS, Sal B and protocatechualdehyde on endothelial permeability in TNF-α-induced HUVECs were studied using Transwell polycarbonate membrane. It has been found that ESM, DSS and Sal B markedly reduced the increased endothelial permeability induced by TNF-α; the effects of pure DSS and Sal B were not as good as the mixture ESM, suggesting that different ingredients in ESM were cooperating with one another in action, which is helpful to decrease the medicinal dose and reduce the undesired effects in clinical use.In addition the effects of ESM, DSS and Sal B on transmembrane adhesive protein (vascular endothelial cadherin, VE-cadherin) complex and signal molecules associated with endothelial permeability regulation, such as vascular endothelial growth factor (VEGF) and extracellular signal-regulated kinase (ERK), were investigated. We found that ESM, DSS and Sal B significantly attenuated the VEGF expression; blockaded ERK activation; repressed the tyrosine phosphorylation of VE-cadherin and its signaling partnerβ-catenin, and blocked disassociation ofβ-catenin with cytoskeleton in TNF-α-induced HUVECs. It is inferred that ESM and its active ingredients may exert protective effects on endothelial barrier function through inactivation of ERK, down-regulation of VEGF and subsequent maintenance of the endothelial junction structure.The results of this research are very meaningful for elucidation of the action characters of Salvia Miltiorrhiza on endothelial cells and provide theoretical and experimental basis for modernization of this traditional Chinese medicine and its development for new medicinal applications.