The Study Of Atorvastatin Enhancing The Anti-inflammatory Injury Capability Of Vascular Endothelial Cells By Up-regulating The Expression Of Heme Oxygenase-1

Objective:The present stuty used rats and human umbilical vein endothelial cells(HUVEC)as the research object to investigate whether atorvastatin could induce the high expression of heme oxygenase-1(HO-1)protein and increase the production of bilirubin in vascular endothelial cells in a dose-dependent manner;whether “high-dose statins ”could more significantly activate HO-1 and increase the generation of bilirubin,thus enhanced the ability of endothelial cells to antagonize the inflammatory injury which was mediated by tumor necrosis factor ?(TNF-?)and lipopolysaccharide(LPS).Methods:The whole experiment was divided into two parts:cell experiment and animal experiment.The first part(Cell experiment): HUVEC were cultured in vitro and then randomly divided into five groups.They were incubated respectively with different concentrations of atorvastatin(0,1,2,5,10 ?mol/L)for 24 hours.The quantity of HO-1 protein expression in HUVEC and the concentration of bilirubin in the supernatant were measured.Additionally,the other cultured HUVEC were randomly divided into 5 groups and incubated respectively under different conditions for 24 hours:control group(incubated with pure medium),high-dose statin group(incubated with Atorvastatin 10 ?mol/L),HO-1 blocked group(incubated with Atorvastatin 10 ?mol/L+ ZnPP IX 10 ?mol/L),low-dose statin group(incubated with Atorvastatin 2 ?mol/L),bilirubin group(incubated with bilirubin 5 ?mol/L).Then all the HUVEC in the 5 groups were treated with TNF-?(10 ng/L)for 12 hours.The concentration of lactate dehydrogenase(LDH),monocyte chemoattractant protein-1(MCP-1),malondialdehyde(MDA),nitric oxide(NO)in the supernatant of each group were measured and the cell apoptosis rate and the proliferation activity viability of HUVEC were also detected.The second part(Animal experiment): The male SD rats were randomly divided into four groups(n=10)and given with different drugs daily for 2 consecutive days:control group(saline 10 mL by gavage),high-dose statin group(atorvastatin 10 mg/kg by gavage),low-dose statin group(atorvastatin 2 mg/kg by gavage),HO-1 blocked group(atorvastatin 10 mg/kg by gavage and ZnPP IX 5mg/kg by intraperitoneal injection).Then five rats from each group were randomly selected to be executed.the blood was taken through the heart to determine the concentration of serum bilirubin and Alanine aminotransferase(ALT),the descending aorta was taken to measure the HO-1 protein expression.The remaining rats in each group were received lipopolysaccharide(LPS)5mg/kg by intraperitoneal injection,12 hours later,the blood was was taken through the heart to detect the serum levels of malondialdehyde(MDA),nitric oxide(NO),endothelin(ET-1),endothelial protein C receptor(EPCR),von Willebrand factor(vWF)and thrombomodulin(TM),the number of circulating endothelial cells(CEC)was also measured by flow cytometry.Result:1.Atorvastatin can increase HUVEC expression of HO-1 protein and production of bilirubin in a dose-dependent manner,in addition,it also can decrease the generation of MCP-1?MDA?LDH and apoptosis rate of HUVEC and increase the generation of NO and the proliferation activity of HUVEC after the intervention with TNF-?.Moreover,giving bilirubin can achieve the similar effects with atorvastatin whereas the use of ZnPP IX with atorvastatin can eliminate the above mentioned effects of atorvastatin.2.Both high-dose atorvastatin and low-dose atorvastatin treatment can significantly increase the expression of HO-1 and the serum bilirubin concentration.The application of atorvastatin can also decrease the concentration of MDA?ET-1?EPCR?vWF?TM and the number of CEC and increase the serum NO production after treated with LPS in rats.high-dose statins can lead to more significant changes on the above indicator than low-dose statins,while the addition of ZnPP IX can eliminate the above mentioned effects of atorvastatin.Conclusion:1.Atorvastatin could increase the expression of HO-1 protein and the production of bilirubin in HUVEC and rat vascular tissue cells in a dose-dependent manner.2.Compared with low-dose atorvastatin,highdose atorvastatin could more effectively induce the expression of HO-1 and inhibit the inflammatory injury of endothelial cells in vitro or in vivo which is mediated by TNF-? or LPS.3.Bilirubin may be one of the effector molecules that mediate HO-1 to protect endothelial cells against inflammatory injury.