Abstract: AIM: To investigate the effects of combined use of dexamethasone and cyclophosphamide on the proliferation of human umbilical vein endothelialcells (HUVECs) and the expression of mRNA of intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1). METHODS: The HUVECs were respectively incubated for 24,48 or 72 h with dexamethasone or cyclophosphamide with different concentration. The proliferation of HUVECs was determined with methyl thiazolyl tetrazolium(MTT) in different time. The half maximal inhibitory concentration(IC₅₀) was calculated. The levels of mRNA of ICAM-1 and MCP-1 were measured after HUVECs being incubated with dexamethasone and cyclophosphamide respectively and collectively in the concentration of IC50 for 48 hours. RESULTS: Dexamethasone or cyclophosphamide inhibited the proliferation of HUVECs in a dose-and time-dependent manner. The IC₅₀ of dexamethasone and cyclophosphamide was 0.74 mg/mL and 1.87 mg, respectively. The levels of ICAM-1 and MCP-1 mRNA in HUVECs had no difference when HUVECs were incubated with either dexamethasone or cyclophosphamide, yet the levels were significantly decreased as compared with controls (P<0.05). ICAM-1 and MCP-1 mRNA levels in HUVECs were lower as HUVECs being collectively treated with dexamethasone and cyclophosphamide(P<0.05). CONCLUSION: Dexamethasone and cyclophosphamide can significantly inhibit the proliferation of vascular endothelial cells and expression of ICAM-1 and MCP-1, thus producing notable protective effect on the blood vessels. This findings may supply basis for clinical therapy strategy for vasculitis.

Key words: human umbilical vein endothelial cells, glucocorticoid, cyclophosphamide, intercellular adhesion molecules, monocyte chemotactic factor