Effect of oxidized High density lipoprotein on angiotensinConverting Enzyme of human vascular endothelial cell.

Objective To investigate the effect of oxidized high density lipoprotein(ox-HDL) on the gene and protein expression of angiotensin-converting enzyme(ACE) in human umbilical vein endothelial cells(HUVECs).Methods Pproducing ox-HDL from human fresh plasma,HUVECs of 3～6th passage were rolled into the experiment and divided into three groups:(1)cells cultured with equivalence Serum-free medium as control;(2)Various concentrations groups of ox-HDL:HUVECs were treated with ox-HDL(20mg/L、40mg/L、80mg/L) for 24 hours;(3) In a time-control experiment,HUVECs were treated with ox-HDL at the final concentration of 40mg/L for 6,12 and 24 hours,respectively.Changes in both gene and protein expression of ACE were determined with reverse transcription polymerase chain reaction RT-PCR) and Western blot analysis technique,respectively.Results ox-HDL induced a concentration and time dependent increase in both gene and protein expression of ACE.Compared with control group,treatment of HUVECs with ox-HDL at the concentration of 20、40、80mg/L stimulated 1.43、2.41 and 2.98 fold increase in the ACE mRNA expression,As well As 1.32、2.0 and 2.54 fold increase in their protein expression,respectively.After treatment of HUVECs with ox-HDL for 6,12 and 24 hours at the concentration of 40mg/L,the ACE gene expression increased 1.64、2.08 and 2.43 fold,and its protein expression increased 1.52、1.78 and 1.99 fold;respectively.Conclusion ox-HDL up-regulates the protein and gene expression of ACE in HUVECs in a concentration and time dependent manner.