烟酸对实验性动脉粥样硬化兔主动脉斑块形成和MK2表达的影响

目的探讨烟酸对动脉粥样硬化斑块形成及动脉壁MK2 mRNA表达的影响。方法 16只雄性新西兰大白兔给予高脂饮食8周后,随机分为高脂血症组(n=8)和烟酸组(n=8),高脂血症组继续饲以高脂饲料6周,烟酸组在高脂饮食基础上给予烟酸200 mg/(kg.d)]6周。另选8只兔给予普通饮食14周作为正常对照组。14周末处死动物进行主动脉病理学检测,采用实时定量PCR检测各组兔主动脉壁MK2 mRNA的表达。结果与正常对照组相比,高脂血症组总胆固醇和低密度脂蛋白胆固醇水平明显升高,主动脉内膜厚度和斑块面积显著增加,MK2 mRNA表达显著增加(P0.01)。与高脂血症组相比,烟酸组总胆固醇和低密度脂蛋白胆固醇水平显著降低,高密度脂蛋白胆固醇水平升高,主动脉内膜厚度和斑块面积显著减少,MK2 mRNA表达也显著减少(P均0.01)。MK2 mRNA表达量与动脉粥样硬化斑块面积(r=0.919,P0.01)和内膜厚度(r=0.863,P0.01)呈正相关。结论烟酸抗动脉粥样硬化作用除与其降脂作用有关外,还可能与其降低MK2 mRNA水平有关。

Effect of Niacin on Plaques Formation and Expression of MK2 mRNA in Aorta of Experimental Atherosclerosis Rabbit

Aim To investigate the effects of niacin on the atherosclerotic plaques formation and MK2 mRNA expression of aorta. Methods 16 New Zealand white rabbits were fed with high-fat diet for 8 weeks,and then were randomly divided into two groups: hyperlipidemia group(n=8) which maintained high-fat diet for 6 weeks,niacin treatment group(n=8) which maintained high-fat diet supplemented with niacin(200 mg/(kg · d))for 6 weeks.Control rabbits(n=8) were fed with normal diet for 14 weeks.At the end of the study,all rabbits were sacrificed to detect the histopathological changes and MK2 mRNA expression of the aortas. Results Rabbits fed with high-fat diet showed higher serum levels of total cholesterol and low density lipoprotein cholesterol(LDLC),more aorta endometrial thickness,plaque area and MK2 mRNA expression(all P><0.01).Compared with hyperlipidemia group,rabbits treated with niacin showed less serum levels of total cholesterol and LDLC,less aorta endometrial thickness,plaque area and MK2 mRNA expression(all P><0.01).MK2 mRNA expression was positively correlated with atherosclerotic plaque area(r=0.82,P><0.01) and endometrial thickness(r=0.863,P><0.01). Conclusion Niacin''s role of anti-atherosclerosis is not only due to its lipid-lowering effect,but also may be related to its MK2 mRNA-lowering effect.