Aim To investigate the effects of oxidized low density lipoprotein(ox-LDL) and atorvastatin on gene and protein expression of angiotensin-converting enzyme-2(ACE-2) in human umbilical vein endothelial cells(HUVEC).Methods HUVEC cultured with equal serum-free medium were used as control.Different concentration groups of ox-LDL and atorvastatin: HUVEC were treated with ox-LDL(20,40 and 80 mg/L) and atorvastatin(1,5 and 10 μmol/L) for 24 h,respectively.In a timecontrol experiment,HUVEC were treated with ox-LDL at final concentration of 40 mg/L and atorvastatin of 5 μmol/L for 6,12 and 24 h,respectively.HUVEC were preincubated with atorvastatin(5 μmol/L) for 1 h and then cocultured with ox-LDL(40 mg/L) for 24 h.Changes in both gene and protein expression of ACE-2 were determined by reverse transcription-polymerase chain reaction(RT-PCR) and Western blot analysis technique,respectively.Results Ox-LDL induced a concentration and time dependent decrease in gene and protein expression of ACE-2.When compared with that of control group,ACE-2 mRNA expression decreased to 73%,51%,33% and protein expression decreased to 81%,50% and 32%,respectively,after treated with different concentrations of ox-LDL(p< 0.01).When treated with ox-LDL for 6,12 and 24 h at concentration of 40 mg/L ox-LDL,ACE-2 mRNA expression in HUVEC decreased to 66%,55% and 50% when compared with that of control group( p<0.01),and protein expression decreased to 63%,53% and 49%(p< 0.01),respectively.Gene expression and protein expression of ACE-2 in groups treated with atorvastatin alone showed no significant difference when compared with that of control groups( p> 0.05).Pretreatment of HUVEC with simvastatin(5 μmol/L) for 1 h could obviously inhibited 40 mg/L ox