Effects Of Niacin On LPL And ABCA1 Expression Of Aorta In Hypercholesterolemic Rabbits

Aim To observe antiatherogenic effects of niacin in hypercholesterolemic rabbits.To explore the effects of niacin on expression of LPL and ABCA1 in the aorta of hypercholesterolemic rabbits and its possible antiatherogenic mechanisms.Methods Ten male New Zealand white rabbits were fed with 1% cholesterol, 7.5% protein, 8% lard diet for 8 weeks, and then were randomly divided into two groups:(l) starch group: maintained cholesterol diet and starch for 6 weeks.(2) niacin group: the same cholesterol diet supplemented with niacin[400mg/(kg·d)]for 6 weeks. And control group (n=5)was fed with normal diet for 14 weeks. At 0th week,8th week and 14th week,serum lipid levels were detected.At the end of the experiment, atherosclerotic lesions were measured by experienced pathologist under BeiHang Pathology Imaging Analysis System. Intimal thickness and intima/media thickness were also measued by SPOT/ver3.5 Analysis Software. LPL and ABCA1 expression in aorta were measured by immunohistochemistry and evaluated by semiquantitative analysis.Results After 6-week niacin treatment, the levels of total cholesterol(TC), low-density lipoprotein cholesterol(LDL-C), triglycerides(TG) were decreased by 43.9%, 47.0% and 44.3% respectively, high-density lipoprotein cholesterol(HDL-C) was increased markedly(all p<0.001). Compared with starch group,the surface area of atherosclerotic lesions reduced 1.97-fold, intimal thickness and intima/media thickness reduced 2.87-fold and 3.70-fold respectively in niacin group. Niacin downregulated LPL and upregulated ABCA1 expression in the aorta.Conclusions Niacin has antiatherogenic effects.Theantiatherogenic mechanisms of niacin may be correlated to the downregulation of LPL and upregulation of ABCA1 in the aorta.