The Expression Of Inflammatory Mediators And The Mechanism In Atherosclerosis Of Rabbit

Objectives:To observe expression of nuclear factor kappaB(NF-κB),tumor necrosis factor-alpha(TNF-α),vascular cell adhesion molecule-1(VCAM-1)and matrix metalloproteinase-2(MMP-2)in the aortic wall of atherosclerosis(AS)of rabbits and to investigate the role of inflammatory mediators on development of atherosclerosis.Methods:A total of 18 New Zealand White male rabbits weighing 1.8 to 2.4 kg were raised in separate cages according to standard of cleaning animal.After adaptability fed one week,they were randomly assigned into two groups:(1)One group of rabbits (control group,group C,N=6)had whole-grain common diet;(2)The another group (model group,N=12)had high-cholesterol diet(contains 1%cholesterol,10%yolk power,5%lard).Model group rabbits were underwent aortic balloon injury(inserted balloon vessel in separated left femoral artery and injured)and injected penicillin 10millionU/kg after 2 weeks of high-cholesterol diet.At the end of 12^thweek all of rabbits were weighed and sacrificed and blood was drawn from the marginal ear vein for analysis of cholesterol,triglyceride,low density lipoprotein-cholesterol(LDL-C), high density lipoprotein-cholesterol(HDL-C).Separated the whole aorta(from ascending aorta to abdominal aorta)and cut it from thoracic aorta.The upper part was preserved in -80℃refrigerator,the part that was underwent aortic balloon injury fixed in 4%paraformaldehyde for 3 hours and then embedded in paraffin.The expression of VCAM-1 and MMP-2 was examined with immuno-histochemical technique.The expression of NF-κB mRNA and TNF-αmRNA were detected with RT-PCR.Results:The body weight in two groups were remarkably increased after 12 weeks. The serum lipid of model group were significantly elevated compared with the baseline levels and control group(P＜0.05).Pathological specimen appearance:Aortic wall of control group rabbit was thin,ductility and not easily broken.Their intimae were transparent and had no plaque on surface.In model group,aortic wall became thicker and more friable and intimae became gray and atherosclerotic plaques were seen.In light microscope,aortic wall of control group rabbit was very smooth and there are no foam cells.But aortic wall was significantly thick in model group.Many inflammatory cells and foam cells in intima.There are a mount of cholesterol crystal in severe ones.The result of immuno-histochemical technique:expression of MMP-2 in model group was strong positive compared with control group.And expression of VCAM-1 in model group was positive,compared with control group.The result of RT-PCR:expression of NF-κB mRNA were very small amount in control group and expression of TNF-αmRNA was negative;however expression of NF-κB mRNA and TNF-αmRNA were a large amount in model group.Conclusions:expression of NF-κB,TNF-α,VCAM-1 and MMP-2 in model group was strong positive compared with control group and the finflammatory mediators may play an important role on development of atherosclerosis.