11β/HSD1与糖脂代谢异常的相关关系研究

The role of 11β/HSD1 on disorder of glycolipid metabolism

目的:探讨11β-羟基类固醇脱氢酶1(11β-hydroxysteroid dehydrogenase,11β/HSD1)对机体糖脂代谢异常的影响及其在肥胖和胰岛素抵抗发生发展过程中的作用及机制。方法:首先构建脂肪组织特异性敲除11β/HSD1(Fabp-11β/HSD1-/-)小鼠。然后选择5周龄Fabp-11β/HSD1-/-小鼠和正常C57BL/6小鼠各5只,建立高脂饮食诱导的肥胖(DIO)小鼠模型,分别在喂食5周和6周时进行腹腔葡萄糖耐量试验(IPGTT)和胰岛素耐量试验(ITT),喂食12周后处死并称量皮下及内脏脂肪重量,采用HE染色方法观察脂肪组织内脂肪空泡改变程度,取血检测血糖、甘油三酯、胆固醇、尿素、肌酐等血清生化指标,同时应用Western blot与QRT-PCR方法检测脂肪组织中11β/HSD1表达和糖脂代谢相关转录因子的蛋白表达情况。结果:脂肪组织特异性敲除11β/HSD1小鼠构建成功。高脂喂养12周后两组小鼠体重、内脏脂肪湿重没有明显差异。Fabp-11β/HSD1-/-组小鼠血清空腹血糖明显低于正常组,其他生化指标没有明显改变,但Fabp-11β/HSD1-/-组小鼠脂肪组织HE染色可见脂肪空泡比正常组小,且糖耐量和胰岛素敏感性明显高于对照组,Western blot与QRT-PCR结果显示Fabp-11β/HSD1-/-小鼠脂肪组织中11β/HSD1、PPAR-γ、C/EPB-α的蛋白表达量明显低于正常组。结论:在高脂饮食下脂肪组织内11β/HSD1表达的下调可减少脂肪细胞内脂滴的沉积,一定程度上改善机体对胰岛素敏感性的下降。

Objective：To investigate the effect of 11β-hydroxysteroid dehydrogenase1（11β / HSD1）on glycolipid abnormalities and its role in the development and progression of obesity and insulin resistance. Methods：The adipocyte-specific-11β/HSD1 knockout mice were constructed firstly. Five mice of 5 weeks-old adipocyte-specific-11β/HSD1 knockout mice and C57BL/6 mice were selected separately to establish the model of obesity（DIO）induced by high-fat diet. After feeding 5 and 6 weeks,mice were processed intraperitoneal glucose tolerance test（IPGTT）and insulin tolerance test（ITT）,respectively. Mice were sacrificed after feeding 12 weeks,and the weight of body and visceral fat were measured,hematoxylin-eosin staining（HE）was subsequently used to assess the degree of fat vacuoles change. The levels of blood glucose,triglyceride,cholesterol,urea and creatinine were also detected. Expression of 11β/HSD1 and some markers associated with glycolipid metabolism were analyzed by Western blotting and quantitative real-time PCR. Results：The adipocyte-specific-11β/HSD1 knockout mice were constructed successfully. There was no significant difference in body weight,visceral fat weight between the two groups,but the adipocyte-specific-11β/HSD1 knockout mice decreased concentrations of serum glucose and size of adipocyte,and increased glucose tolerance and insulin sensitivity,compared with the control group. The protein levels of 11β/HSD1 and transcription factors peroxisome proliferator-activated receptor gamma（PPAR-γ） and CCAAT enhancer-binding proteins alpha（C/EPB-α） were obviously lower in the adipose tissues of adipocyte-specific-11β/HSD1 knockout mice than that of the control group. Conclusion：The down-regulation of 11β/HSD1 expression in adipose tissues can reduce the lipid droplets deposition and improve the insulin sensitivity in DIO.