高脂饲养致小鼠胰岛素抵抗对脂肪肝形成的影响  

Effect of insulin resistance on fatty liver in high-fat diet-fed mice

作　　者：韦雪梅[1] 邱霓[1] 熊燕[1] 

机构地区：[1]广州医科大学药学院,广州蛇毒研究所,广东广州511436

出　　处：《中国病理生理杂志》2016年第10期1875-1880,共6页Chinese Journal of Pathophysiology

基　　金：中国博士后基金资助项目(No.2012M521590;No.2013T60792);广东省自然科学基金资金项目(No.s2013040014350)

摘　　要：目的:探讨高脂饲养致小鼠脂肪肝形成的机制。方法:随机将8周雄性C57BL/6J小鼠分成高脂饲养组(给予含60%卡路里的高饱和脂肪酸饲养)和正常对照组,饲养12周。监测体重、肝重、血甘油三酯、血总胆固醇、血糖和血胰岛素水平,通过高胰岛素正葡萄糖钳夹实验反映胰岛素敏感性,HE染色、苏丹IV染色及肝脂含量反映肝组织脂质沉积情况,确定高脂饲养致小鼠脂肪肝的形成。通过Western blot法检测磷酸化胰岛素受体底物1(IRS1)和蛋白激酶B(Akt)水平反映胰岛素信号通路激活情况,检测固醇调节元件结合蛋白1(SREBP-1)和脂肪酸合成酶(FAS)蛋白水平反映肝内脂质合成的情况。结果:高脂饲养组小鼠体重及肝重较正常对照组小鼠明显增加。与正常对照组相比,高脂组血和肝组织内甘油三酯和总胆固醇含量显著升高,血清胰岛素水平升高,葡萄糖输注率减少,磷酸化IRS1和Akt水平降低。肝组织HE染色可见高脂组肝细胞胞浆内充满大量脂肪空泡,苏丹IV染色可见肝细胞内存在大量大小不一的红色脂滴;SREBP-1和FAS蛋白水平明显升高。给予外源性油酸干预原代正常肝细胞48 h,磷酸化IRS1和Akt水平呈浓度依赖性减低,而SREBP-1和FAS蛋白表达明显升高。结论:高脂饲养导致小鼠肝脏发生胰岛素抵抗,并通过激活SREBP-FAS脂肪合成途径,促进肝脏脂质沉积,从而诱发脂肪肝。AIM ： To study the influence of insulin resistance on fatty liver in the mice fed with high-fat diet （HFD）. METHODS： Male 8 -week-old C57BL / 6J mice were randomly divided into HFD group （with 60% calories by high saturated fatty acid） and control group （with chow diet）. The mice in both groups were fed for 12 weeks. The body weight, liver weight, serum triglyceride （TG） and total cholesterol （TC） , and blood glucose and insulin levels were measured. Hyperinsulinemic euglycemic clamp experiment was applied to reflect insulin sensitivity. The lipid deposition in the liver was analyzed by HE staining, Sudan IV staining and measurement of liver fat content. The phosphorylation levels of IRS1 and Akt, and the protein levels of SREBP-1 and FAS were determined by Western blot to reflect the activities of insulin signaling and lipid synthesis. RESULTS ： Compared with control group, the body weight and liver weight were significantly increased in HFD group. TG and TC contents in serum and liver tissues were remarkably increased in HFD group. High-fat diet induced insulin resistance, as evidenced by increased serum insulin levels, reduced glucose infusion rate and decreases in IRS1 and Akt phosphorylation levels. In livers of HFD group, HE staining showed that the cytoplasm of hepatocytes was filled with vacuoles. Sudan IV staining also displayed that many different sizes of red lipid drops existed in the hepatocytes, and the protein levels of SREBP-1 and FAS were significantly increased. In primary normal hepatocytes with exogenous oleic acid intervention for 48 h, the phosphorylation levels of IRS1 and Akt were reduced, and the protein expression of SREBP-1 and FAS was significantly increased in a dose-dependent manner. CONCLUSION ： Feeding with HFD leads to insulin resistance, resulting in activation of lipid synthesis and accumulation of lipid deposition in the liver, thus inducing fatty liver.

关 键 词：胰岛素抵抗 脂肪肝 高脂饮食 

分 类 号：R363.2[医药卫生—病理学]