Changes In Serum Levels Of MCP-1and ICAM-1in Transgenic Mouse Overexpressing CXCL16

BACKGROUND:Atherosclerosis(AS) is a large class of diseases threatening humanhealth. With the improved living standards of our people and a change in eating habits,the disease has become the leading cause of death in China. With further research, theresearchers have come to realize the importance of the inflammatory response in theAS mechanism. CXC chemokine ligand16(CXCL16) belongs to a chemokine CXCsubfamily, by interacting with the G protein coupled receptors CXCL16can induce avariety of types of leukocytes involved in the AS inflammatory response.In AS,rheumatic heart valve disease, infective endo-carditis, CXCL16expresses inmacrophages and arterial smooth muscle cells and endothelial cells. Except forchemotaxis CXCL16promotes smooth muscle proliferation, inflammatory celladhesion, promotes the macrophages’ phagocytosis of lipid forming foam cells as ascavenger receptor. In addition, recent studies have shown that CXCL16alsopromotes angiogenesis which is AS related.Our former experiment using thetransgenic method constructed the model which can overexpress CXCL16,to somedegree domenstrate the CXCL16promote AS whose evidences include theupregulated blood lipid levels,Matrix metalloproteinase-9’s expression and thepathology change. This experiment on the basis of the original work, use real-timequantitative PCR (RT-PCR) to detect the CXCL16mRNA in aortic wall.The serumconcentration of CXCL16under high fat condition was measured using ELISA, thiswill improve the authentication of this transgenic model. Monocyte chemotacticproteins-1(MCP-1) and Intercellular adhesion molecule-1(ICAM-1) are inflammatoryfactor which gather at the criminal site of AS.Lots of CXCL16-knockout or clinicalexperiments were found contradictory.The effect of this gene wether to promote orinhibit AS remains concealed. Objective:1. To observe the expression of CXCL16in blood serum and aortic sinusin transgenic mouse.2.To observe CXCL16overexpression’s impact on AS inflammatorycytokines MCP-1, ICAM-1which are important to AS.Method: The offsprings of CXCL16transgenic mice by microinjection areheterozygotes.Place the PCR-positive offsprings in the same cage to obtainhomozygotes.20randomly selected CXCL16transgenic homozygous mice formedtransgenic group,20randomly selected C57BL/6j formed inbred group.Within eachgroup randomly selected10mice were fed with high fat diet for16weeks, the restnormal diet. Test groups:(1) high-fat transgenic group (2) high-fat inbred group (3)normal-diet transgenic group (4) normal-diet inbred group. Using the ELISA testserum MCP-1, ICAM-1and CXCL16concentrations after18weeks; real-timequantitative RT-PCR detect the aorta CXCL16mRNA content; Immunohistochemicalanalysis of MCP-1,ICAM-1expression.Results:1.The levels of total cholesterol(TC) and low-density lipoproteincholesterol(LDL-C) in high-fat transgenic group are ligher than in normal-dietgransgenic group,the difference is statistically significant(P<0.05).The levels of totalcholesterol(TC) and low-density lipoprotein cholesterol(LDL-C) in high-fat inbredgroup are ligher than in normal-diet inbred group,the difference is statisticallysignificant(P<0.05). The levels of total cholesterol(TC) and low-density lipoproteincholesterol(LDL-C) in high-fat transgenic group are ligher than in high-fat inbredgroup,the difference is statistically significant(P<0.05).2. CXCL16mRNA expression of the aortic wall and the serum levels of CXCL16inhigh-fat transgenic group and normal-diet transgenic group are respectively higherthan in high-fat inbred group and normal-diet inbred group(P<0.05); CXCL16mRNAexpression of the aortic wall and the serum levels of CXCL16in high-fat transgenicgroup and high-fat inbred group are respectively higher than in normal-diet transgenicgroup and normal-diet inbred group(P<0.05). 3.The serum level of MCP-1is significantly increased in the high-fat transgenic groupcomparing with high-fat inbred group and normal-diet transgenic group(P<0.01).Between normal-diet transgenic group and normal-diet inbred group there isno statistical difference;Between high-fat inbred and normal-diet inbred group there isalso no statistical difference.4. The serum level of ICAM-1is significantly increased in the high-fat transgenicgroup comparing with high-fat inbred group and normal-diet transgenicgroup(P<0.01).In the high-fat transgenic group ICAM-1is higher comparing withhigh-fat inbred group and normal-diet transgenic group(P<0.01).5. Immunohistochemistry shows higher expression of MCP-1and ICAM-1in theaortic wall and aortic velves in the high-fat transgenic group than in the high-fatinbred group.Conclusions：1.A confirmation of the overexpression of CXCL16in the transgenic model of mice.2.CXCL16over-expression increases the MCP-1, ICAM-1in the serum, as well asthe expression of in the aortic wall, this function may be to promote the AS lesions.