Abstract: Objective To observe whether folic acid(FA),VB 6 and VB 12 have effects of inhibiting vascular cell ahesion molecule-1(VCAM-1)expression in cultured endothlial cells in vitro.Methods Cultured rat aortic endothelial cells were inoculated in vitro and divided into five groups:control group,1 mmol/L homocysteine(Hcy)group,inhibiting group Ⅰ(1 mmol/L Hcy+5μmol/L FA),inhibiting groupⅡ(1 mmol/L Hcy+5μmol/L FA+5 nmol/L VB12),inhibiting groupⅢ(1 mmol/LHcy+5μmol/L FA+0.1μmol/L VB 6+5nmol/LVB12).The expression of VCAM-1 mRNA in rat aortic endo the lial cella induced by 1 mmol/L Hcy for 6 hours was assayed by RT-PCR.Results The expression level of NF-κB protein and VCAM-1 mRNA was up-regulated in the cultured rat aortic endothelial cells induced by 1.0 mmol/L Hcy for 6hr and 24hr respectively,and the rate of endo the liocyte-monocyte adhesion increased significantly.The effects induced by Hcy could be inhibited significantly by FA,VB6 and VB 12,and the inhibitory effects adding FA,VB 6 and VB 12 toge ther were better than other treatments.Conclusion FA,VB 6 and VB 12 may alleviate the injuries induced by Hcy in cultured endothelial cells in vitro through inhibiting the expression of NF-κB protein and VCAM 21 mRNA and decreasing the rate of endotheliocyte-monocyte adhesion.