Aim To examine the expression of NARC-1 protein in atherosclerotic lesion of New Zealand rabbits. Methods Male purebred New Zealand rabbits with adaptation feeding for 1 week,were randomly divided into control group(n = 8) and high-cholesterol group(n = 8).The control group was given a normal control diet and the high-fat group was fed a high-cholesterol diet(2%cholesterol).All rabbits were euthanized at the end of the 8-week experiment. Plasma triglyceride(TG),total cholesterol(TC),high density lipoprotein cholesterol(HDLC) and low density lipoprotein cholesterol(LDLC) were determined by commercially enzymatic methods.Atherosclerosis index(AI) and the HDLC/LDLC ratio were calculated.SudanⅣstaining was used to examine the aortic atherosclerotic lesions.The pathological changes of rabbit aortic preparations was quantified by computer-assisted image analysis of oil red O and HE staining using Image-Pro Plus image analysis software.NARC-1 protein distribution and expression was analyzed by immunohistochemistry and Western blotting.Results Plasma TC,HDLC and LDLC concentrations,and AI were markedly increased, but the HDLC/LDLC ratio was markedly decreased in high-cholesterol group.High-cholesterol diet induced significant aortic atherosclerotic lesions.Histopathology analysis showed that aortic intima was obviously thickened and the intima/media thickness ratio was significantly increased in high-cholesterol group rabbits.Oil red O staining indicated that the number of foam cells in artery endothelium were markedly increased in the high-cholesterol group compared with the control group.HE staining revealed the aortic intima in control rabbits was intact and thin,compared to thickened aortic intima and remarkable atherosclerotic plaques in high-fat group rabbits.Immunohistochemical detection showed NARC-1 protein was found in the intima plaque and located in cytoplasma and plasma membrane of foam cells in high-fat group. Western blotting analysis also indicated NARC-1 protein expression was significantly elevated in the aortic atherosclerotic plaque of high-fat group rabbits.Conclusion The high-cholesterol diet induced aortic atherosclerotic lesion in New Zealand rabbits.NARC-1 protein was remarkably expressed in aortic atherosclerotic plaque and located in the cytoplasma and plasma membrane of the foam cells in high-fat group rabbits.The results indicate that NABC-1/PCSK9 is one of the important factors involved in atherosclerosis development.