Mechanism of ligustrazini against thrombosis

Objective To investigate the mechanism of Chinese medicine ligustrazini aga inst thrombosis, and the effects of ligustrazini on plasminogen activator i nhibitor (PAI-1) expression in normal endothelial cells and lipopolysacchar ide (LPS) stimulated endothelial cells. Methods Human umbilical vein endothelial cells (HUVECs) were cultured by tr ypsin digestion method. PAI-1 protein in HUVEC conditioned medium was measu red by Sandwich enzyme-linked immunosorbent assay (ELISA), and PAI-I mRNA e xpression was determined by Northern blot analysis. Using electrophoretic m obility shift assay (EMSA), we observed HUVEC nuclear factor-kappa B (NF-ka ppa B) nuclear translocation. Results LPS treatment of cultured HUVECs resulted in a significant increase in PAI-1 protein and mRNA expression by these cells. However, when HUVECs were incubated with LPS plus ligustrazini, the upregulation of PAI-1 by LPS was abated. Moreover, ligustrazini could decrease the basal level of PAI-1 protein and mRNA in HUVECs as compared with control. Nuclear extracts prep ared from HUVECs stimulated by LPS demonstrated that binding to the NF-kB o ligo nucleotide increased as compared with the unstimulated cells, but ligu strazini did not change those binding in the absence or presence of LPS. Conclusions Ligustrazini inhibited both basal and LPS-induced PAI-1 protein and mRNA expression in endothelial cells, and the modulation of PAI-1 in H UVECs by ligustrazini might have other mechanisms rather than NF-kB pathway .