\[Abstract\] Objective To investigate the effect of human cytomegalovirus(HCMV) infection on cholesterol metabolism in smooth muscle cells of the umbilical arteries and the related mechanismsMethods Vascular smooth muscle cells were isolated from umbilical arteries and were challenged with 1 MOI HCMV, and the intercellular content of cholesterol was determined.Cells treated with DMEM/F12 solution containing 3% fetal bovine serum were taken as mock infection controls.The differentially expressed genes were screened by cDNA microarray in each group,and the abnormally expressed genes associated with cholesterol metabolism were identified by fluorescence quantitative RTPCR.Results The intracellular content of cholesterol (\[0.71±0.06\] μmol/106 cells) was significantly higher in HCMV infection group at 72 h after infection compared with that in the control group (t=7.950,P=0.000 2).cDNA microarray and fluorescence quantitative RTPCR showed that the expressions of HMGCoA synthetase and HMGCoA reductase were greatly upregulated compared with those in the mock infection group 48 and 72 h after infection (P<0.01).Conclusion Human cytomegalovirus infection can increase the synthesis of cholesterol through upregulating cholesterol metabolismassociated genes in vascular smooth muscle cells,leading to unbalancd cholesterol metabolism.