中文摘要：

目的观察烟酸干预后对小鼠体内胆固醇逆转运的影响，并探讨其机制。方法14只C57BL／6小鼠随机分为两组，分别给予普通饲料、烟酸添加饲料喂养4周后，腹腔注射经乙酰化-低密度脂蛋白及^3H-胆固醇处理过的小鼠巨噬细胞悬液（0．5mid鼠，细胞数为5．0×10^6）．单独笼养24h后测定粪便中的3H-胆固醇含量（占注射总量的百分比）；逆转录聚合酶链反应测定小鼠肝脏和小肠三磷酸腺苷结合盒转运体G5、肝X受体amRNA及肝脏胆固醇7a羟化酶mRNA表达并用Western blot印迹检测肝脏和小肠的三磷酸腺苷结合盒转运体G5和肝X受体α蛋白表达。结果与对照组比较，烟酸组小鼠肝脏和小肠的三磷酸腺苷结合盒转运体G5、肝X受体α，肝脏胆固醇7α羟化酶mRNA水平和肝肠的三磷酸腺苷结合盒转运体G5、肝X受体α蛋白质水平均增高，粪便中的胆固醇流出率增加21％。结论烟酸可能通过上调体内肝X受体α，从而刺激三磷酸腺苷结合盒转运体G5、胆固醇7α羟化酶表达来发挥促进小鼠体内胆固醇逆转运作用。

英文摘要：

Aim To explore the effect of niacin on reverse cholesterol transport in mice in vivo and the possible mechanism. Methods 14 C57BL/6 mouse were treated with ordinary diet and niacin in diet for 4 weeks, then the semiee were injected intraperitoneaUy with 3H-cholesterol-labeled and cholesterol-loaded raw 264.7 maerophages （0.5 mL/miee, the amount of cells achieve 5.0 × 10^6 ） . After 24 h, feces were collected and analyzed the appearance of 3H-tracer （ as the percentage of the total injected counts）. Reverse transcription polymerase chain reaction （RT-PCR） were used to evaluate ABCG5; CYP7α, mRNA of liver and ABCG5, LXRα mRNA of intestina expression. And the level of ABCG5, LXRα proteins of liver and intestina was analyzed by Western blot. Results It was observed that niacin increased reverse cholesterol transport by 21% in mice in vivoin contrast to the control （P〈0.05）. NiacinincreatedABCGS; CYP7α, LXRαmRNAofliverandABCG5, LXRα mRNA of intestina expression, while having the same effect on the expression of liver, and intestina, ABCG5 and LXRα protein. Conclusion These results suppose that niacin promtes reverse cholesterol transport by increasing ABCG5 and CYP7αexpression Milch is stimulated by LXRα.