Objective: To observe the joint effect of shear stress and Shenlian (SL) extracts on E-selectin and neuclear factor κB(NF-κB) expression in endothelial cells. Method: 2×2 factorial design was employed to analyze the interactions between shear stress and SL extracts. Bioflux1000 microfluidic device was used to control two levels of shear stress. E-selectin and NF-κB expression stimulated by tumor neerosis factor -α(TNF-α) in human umbilical vein endothelial cells(HUVECs) were detected by using immunofluorescence method after pretreatment 10 hours with different level

of shear stress and SL extract. Result: There was an interaction associated with each factor in regulating E-selectin expression. Combined treatment of SL extract with 10 dyn·cm-2 shear stress led to a synergistic decrease in E-selectin expression in endothelial cells. As a single factor

SL extract or shear stress alone could decrease NF-κB expression significantly. Conclusion: Shear stress may influence the SL extract's atheroprotective effect through downregulation of E-selectin via NF-κB in endothelial cells.