【作者】 肖虎；

【导师】 陈璐璐；

【作者基本信息】 华中科技大学 ， 内科学， 2008， 博士

【摘要】 目的:建立高脂喂养的肥胖胰岛素抵抗(insulin resistance,IR)2型糖尿病C57BL/6J小鼠模型。方法:雄性C57BL/6J小鼠30只,随机选择15只小鼠为正常对照(normal control,NC)组,饲以基础饲料。其余15只小鼠喂以高脂饲料,给予单纯高脂饲料,为单纯高脂饮食(high fat diet,HF)组。第24w末时结束动物模型。第8w末和第24w末测定小鼠血糖、血游离脂肪酸(FFA)、血甘油三酯(TG)、血胆固醇(Chol)及血胰岛素,行腹腔葡萄糖注射耐量试验,并根据血糖和血胰岛素值计算ISI和HOMAIR指数(HOMA-IR)。通过以上指标最终确定肥胖的2型DM小鼠模型有无建立及其代谢特点。结果:高脂喂养第8w末时,HF组体重较NC组有明显增加(分别为25.5±0.9g和26.8±1.0g),差异具有显著意义(P<0.01),空腹血糖HF组较NC组明显增加(P<0.01),IPGTT HF组小鼠0min,30min,60min和120min的血糖分别为NC组小鼠对应时点血糖的1.26倍、1.43倍、1.40倍和1.21倍,且差异均具有显著性(P<0.01);第24w末时,HF组小鼠血糖进一步升高,IPGTT HF组小鼠0min,30min,60min和120min的血糖分别为NC组小鼠对应时点血糖的1.67倍、1.71倍、1.92倍和2.20倍,且差异均具有显著性(P均<0.01);同时血FFA,TG和Chol也明显增加,和NC组相比差异具有显著性(P<0.01)。第8wHF组小鼠空腹胰岛素为NC组小鼠的1.8倍(P<0.01),第24w末HF组小鼠空腹胰岛素为NC组小鼠的2.18倍(P<0.01)并且胰岛素敏感性指数ISI下降,IR指数HOMA-IR增高,与NC组相比,差异具有显著性(P<0.01、P<0.01)。结论:高脂饮食诱导的C57BL/6J小鼠具备肥胖、高血糖、脂代谢紊乱、IR和高胰岛素血症的特点。高脂饮食成功的诱导了肥胖、IR的2型糖尿病模型。目的:探讨白藜芦醇改善IR的作用及机制。方法:45只雄性C57BL/6J小鼠随机分为3组(每组15只):正常对照组(标准饲料喂养,NC组),高脂饲料喂养组(高脂饲料喂养,HF组),和白藜芦醇治疗组(HR组),其中白藜芦醇组全程高脂饲料喂养,并从第9周开始用白藜芦醇干预治疗(400mg/kg.day),各组均继续喂养16周,共喂养24周。24周末检测体重、血糖、胰岛素,处死动物,检测皮下脂肪和内脏脂肪含量。留取内脏脂肪组织石蜡切片HE染色观察形态学改变。检测内脏脂肪组织ATGL、PGC-1αmRNA和ATGL蛋白的表达,肝脏组织糖异生相关基因PEPCK、G-6-Pase和FoxOlmRNA的表达水平。结果:与NC组相比,HF组小鼠体重、脂肪含量尤其是内脏脂肪含量明显增高(P<0.01),光镜下内脏脂肪细胞形态变大,ATGL mRNA和蛋白表达减少但无统计学意义,HR组小鼠体重、内脏脂肪含量明显降低(P<0.01),光镜下内脏脂肪细胞形态变小,ATGL mRNA和蛋白表达增加(P<0.05)。与NC组相比,内脏脂肪组织HF组PGC-1αmRNA表达下降,为NC组的56.3%(P<0.01);HR组PGC-1αmRNA达到NC组的90.8%,和HF组相比差异有显著性(P<0.01)。HF组肝脏FoxO1、PEPCK和G-6-P mRNA表达为NC组135.6%,154.8%和164.7%(P<0.05),HR组肝脏FoxO1、PEPCK、G-6-P mRNA表达较HF组降低到NC组的108.4%,105.5%,110.3%(P<0.05)。结论:1.白藜芦醇通过减轻腹型肥胖减轻高脂喂养诱导的IR,内脏脂肪ATGL的表达上调是白藜芦醇减轻内脏肥胖的机制之一;2.白藜芦醇通过促进PGC-1α的表达增加内脏脂肪组织对脂肪的氧化利用;3.长期高脂饮食促进肝脏FoxO1,PEPCK,G-6-Pase基因表达,糖异生增加,导致空腹血糖增加;白藜芦醇能有效降低FoxO1,PEPCK,G-6-Pase基因表达,增强胰岛素信号传导,抑制肝脏糖异生,改善IR和糖代谢。目的:观察白藜芦醇对高脂饮食诱导的小鼠NAFLD的改善作用及其机制。方法:雄性C57BL/6J小鼠45只,随机选择15只小鼠为正常对照(normal control,NC)组,饲以基础饲料。其余30只小鼠喂以高脂饲料,8w末将其随机分为2组:继续给予单纯高脂饲料,为单纯高脂饮食(high fat diet,HF)组;高脂饮食喂养同时给予白藜芦醇400mg/kg/day灌胃,为白藜芦醇干预(HR)组。第24w末时结束动物模型,处死动物,观察肝脏形态学变化。RT-PCR检测肝脏内ATGL和PGC-1αmRNA基因表达,WesternBlot免疫印迹检测肝脏内ATGL蛋白表达水平。结果:HF组出现显著的IR,HR组IR明显减轻。HF组肝脏出现明显脂肪变性,肝组织内ATGL蛋白水平降低到对照组的70.2%(P<0.01)。HR组镜下脂肪变性明显好转,与HF组相比,HR组肝组织内ATGL和PGC-1αmRNA及ATGL蛋白表达增加(P<0.05)。结论:1.白藜芦醇通过减轻IR间接改善NAFLD;2.白藜芦醇可以上调肝脏ATGL的表达和PGC-1αmRNA的表达促进脂解和脂肪的氧化利用而直接改善NAFLD。更多还原

【Abstract】 Objective:To explore the establishment of diabetic mice model.Methods:30 male C57BL/6J mice were randomly divided into normal control group(NC, n=15) and high fat diet(HF,n=15) group.HF group were fed with high fat diet,while the NC group were fed with standard chow diet.All mice received IPGTT in the end of 8 weeks and 24 weeks to evaluate it glucose metabolism.And the plasma free fatty acid (FFA),plasma triglyceride(TG),plasma cholesterol(Chol) and plasma insulin of HF mice were measured.ISI and insulin resistance index were calculated according to the plasma glucose and plasma insulin.Results:24 weeks later,The plasma glucose at Omin,30min,60min and 120min of HF mice were 1.3 times,1.4 times,1.4 times and 1.2 times those of NC group(P<0.01), respectively.Compared with NC group,plasma FFA,TG and Chol of HF mice were also increased and the differences between them had the statistical significance(P<0.01). Compared with NC group,ISI of HF mice were decreased(P<0.01) while the insulin resistance index were increased(P<0.01).Conclusions:The high-fat diet-fed C57BL/6J mouse model is a robust model for type 2 diabetes.The diabetic model that induced by the high fat diet have the characteristics of obesity,hyperglycemia,dyslipidemia,insulin resistance(IR) and hyperinsulinemia. Obojective:To observe the effects of resveratrol on insulin resistance(IR) and explore its related mechanisms.Method:45 male C57BL/6J mice were randomly allocated to three groups(15 mice for each group):normal control group(NC group,fed with standard chow),high fat feeding group(HF group,fed with high fat diet) and resveratrol treated group(HR group).The resveratrol-treated group was fed with high fat diet all the time and received resveratrol administration(400mg/kg.day) except the first 8 weeks.Each group mice were kept 24 weeks before killed.At the end of animal experiment,mice were sacrificed and adipose tissue and liver collected.Weight,blood glucose,insulin were measured,and visceral fat were weighted.Hematoxylin and eosin(HE) staining was used to evaluate pathology changes in visceral fat.ATGL,PGC-1αmRNA and ATGL protein were measured in visceral fat.And also PEPCK,G-6-Pase and FoxOlmRNA expression,involved in gluconeogenesis,were measured.ResultsCompared to NC group,weight and visceral fat index were increased in HF group. Fasting serum insulin(FINS) was elevated and fasting blood glucose was increased in HF group.ATGL protein levels in WAT in HF group equaled to NC group.However, resveratrol administration greatly improved the visceral fat index,FBG,FINS compared with HF group.Compare with NC group,ATGL protein levels in HR group were elevated to 126.9%with the up-regulation of ATGL mRNA expressions in WAT.Compared with NC group,the levels of FoxO1,PEPCK,G-6-Pase in the liver were increased to 135.6%, 154.8%,and 164.7%,respectively(P<0.05) in HF group and decreased to 108.4%, 105.5%,110.3%(P<0.05).Conclusions:Resveratrol administration markedly improved high-fat feeding induced insulin resistance.Administration of resveratrol can result in weight and blood glucose reduction.Elevated expression of ATGL may contribute to the improvement of obesity. Elevated expression of PGC-la can increase fat oxidation.High fat diet induced liver expressions of FoxOl,PEPCK,G-6-Pase,thus promote gluconeogenesis,resulting in higher FBG.Resveratrol can reduce liver expressions of FoxOl,PEPCK,G-6-Pase, strengthen insulin signal conduction,suppress gluconeogenesis and thus regulate glycometabolism. Obojective:To explore the improvement effects of resveratrol on nonalcoholic fatty liver induced by high fat diet,and related mechanisms.Method:45 male C57BL/6J mice were randomly allocated to three groups(15 mice for each group):normal control group(NC group,fed with standard chow),high fat feeding group(HF group,fed with high fat diet) and resveratrol treated group(HR group).The resveratrol-treated group was fed with high fat diet all the time and received resveratrol administration(400mg/kg.day) except the first 8 weeks.Each group mice were kept 24 weeks before killed.At the end of animal experiment,mice were sacrificed and liver pathology changes were measured.RT-PCR was used to detect ATGL and PGC-1αmRNA expressions.WesternBlot was used to measure ATGL protein expression.Results Compared to NC group,Pathology of liver steatosis was observed in light microscope in HF group.ATGL protein levels in HR group were elevated to 135.8%with the up-regulation of ATGL mRNA expressions in liver.The mRNA expression of PGC-1αwere significantly lower in HF group than those in HR group(P<0.01).Conclusions:Administration of resveratrol can promote ATGL expression in fatty liver. Elevated expression of ATGL may contribute to the improvement of fatty liver. Upregulation expression of PGC-la in the liver by resveratrol can result in elevation of lipolysis and fat oxidation.更多还原