利拉鲁肽对低脂联素血症小鼠胆固醇代谢相关基因的影响

Effects of liraglutide on the expression of genes related to cholesterol metabolism in ApoE-/- mice with hypoadiponectinemia

目的 探讨利拉鲁肽（liraglutide）对脂联素基因表达缺陷ApoE基因敲除（ApoE-/-）小鼠胆固醇代谢相关基因的影响.方法 雄性ApoE-/-小鼠36只按随机数字表法随机分为单纯高脂喂养组（HF组,n=10）、空载腺病毒组（GFP组,n=6）、高脂＋脂联素RNAi腺病毒组（ADI组,n=10）、利拉鲁肽治疗的高脂＋脂联素RNAi腺病毒组（HEA组,n=10）.采用扩展胰岛素钳夹术评价其胰岛素敏感性,酶联免疫法测定血浆脂联素水平,实时荧光定量PCR方法 检测肝脏组织胰岛素诱导基因1和2（INSIG1,INSIG2）、固醇调节元件结合蛋白1和2（SREBP-1,SREBP-2）、羟甲基戊二酸单酰辅酶A还原酶（HMGCR）和低密度脂蛋白受体（LDLR）mRNA表达.结果 ADI组血浆总胆固醇、甘油三酯、低密度脂蛋白胆固醇、空腹胰岛素和游离脂肪酸水平较其他3组显著升高（P＜0.01）;而高密度脂蛋白胆固醇水平则显著降低（P＜0.05）.ADI组血浆脂联素水平显著低于HEA、HF和GF组（P＜0.01）.ADI组肝组织INSIG2和LDLR mRNA表达水平较其他3组显著降低（P＜0.01或P＜0.05）;HEA组肝组织HMGCR 和SREBP-2 mRNA表达水平较其他3组明显升高（P＜0.01或P＜0.05）;ADI、HF和GFP组HMGCR和SREBP-2 mRNA表达水平无明显差异.结论 利拉鲁肽可能通过上调脂联素水平调节胆固醇代谢相关基因的表达,从而改善胆固醇代谢紊乱.

Objective To investigate the effects of liraglutide on gene expression related to cholesterol metabolism in ApoE-/-mice with adiponectin deficiency. Methods Thirty six ApoE-/-mice fed with the high-fat diet were subdivided into four groups. One group was given 100 μl（1×109PFU） of adenoviral pAd-U6-GFP（GFP group, n=6）. The second group received 100 μl of adenoviral pAd-U6-Acrp30（ADI group, n=10）. The third group was given 100 μl of adenoviral pAd-U6-Acrp30 and liraglutide（HEA group, n=10） and the fourth group was given only 100 μl sterile saline（HF group, n=10）. Insulin sensitivity and glucose metabolism were assessed by the hyperinsulinemic-euglycemic clamp technique using 3-[3H] glucose as a tracer. Plasma adiponectin level was evaluated using a commercially available ELISA kit. The mRNA expressions of genes involved in cholesterol metabolism were measured by quantitative realtime PCR. Results Fasting blood glucose（FBG）, free fatty acids（FFA）, total cholesterol, triglyceride, low density lipoprotein cholesterol, adiponectin, and fasting plasma insulin（FINS） in ADI mice were significantly higher than those in the other groups（P〈0.01）, while high density lipoprotein cholesterol was significantly lower（P〈0.05）. During the clamp, glucose infusion rate（GIR） in ADI group was significantly lower than the other groups（P〈0.01）, and hepatic glucose production（HGP） significantly higher in ADI group（P〈0.01）. The mRNA expressions of INSIG2 and LDLR in ADI group were significantly down-regulated in HEA group（P〈0.01 or P〈0.05）, while HMGCR and SREBP-2 were significantly up-regulated in HEA group（P〈0.01 or P〈0.05）. Conclusions Liraglutide regulates a number of genes involved in cholesterol metabolism and ameliorates hypercholesterolemia by elevating plasma adiponectin level.