论文部分内容阅读
目的:探讨碳水化合物反应原件结合蛋白(carbohydrate response element binding protein,ChREBP)在2型糖尿病小鼠肝中的表达及其在脂质代谢紊乱中的作用。方法:以10～13周龄的雄性C57BL/BKS基因背景的2型糖尿病模型db/db小鼠作为实验组,年龄、性别匹配的db/m小鼠作为对照组。首先用油红O染色的方法检测肝中沉积的中性脂肪。利用免疫组织化学方法确定ChREBP在肝内的表达分布,随后用Western blot及实时荧光定量PCR等方法分析其在db/db小鼠肝中的表达及活性,以及ChREBP靶基因乙酰辅酶A羧化酶(acetyl-coenzyme A carboxylase 1,Acc-1)、脂肪酸合成酶(fatty acid synthase,Fas)与甘油-3-磷酸酰基转移酶(glycerol-3-phosphate acyltransferase,Gpat)的表达变化。结果:db/db小鼠肝中有明显的脂质沉积现象。ChREBP蛋白弥散表达于正常小鼠肝组织中,在中央静脉周围及汇管区表达较高。在正常小鼠肝细胞内,ChREBP主要存在于胞浆中。但在db/db小鼠肝细胞内,细胞核中的ChREBP水平较对照组小鼠增加了8.2倍(P<0.01)。与之相一致,db/db小鼠肝中涉及脂质合成的一些重要的ChREBP靶基因(包括Acc-1,Fas和Gpat)的表达水平分别增加了2倍(P<0.05)、1.7倍(P<0.05)、4.2倍(P<0.05)。结论:在2型糖尿病小鼠,肝ChREBP的表达和活性的显著增加,激活了一系列与脂质合成相关基因的表达,进而促进脂肪肝的形成。本研究提示ChREBP可能成为治疗脂肪肝的潜在靶点。
Objective: To investigate the expression of carbohydrate response element binding protein (ChREBP) in the liver of type 2 diabetic mice and its role in lipid metabolism disorder. Methods: The db / db mice of 10 ~ 13 weeks old male C57BL / BKS gene background type 2 diabetes model were used as the experimental group and the age and sex matched db / m mice as the control group. First, the method of oil red O staining to detect the liver deposition of neutral fat. Immunohistochemistry was used to determine the distribution of ChREBP in the liver. The expression and activity of ChREBP in liver of db / db mice were analyzed by Western blot and real-time fluorescence quantitative PCR, and the expression of ChREBP target gene acetyl CoA carboxylase acetyl-coenzyme A carboxylase 1 (Acc-1), fatty acid synthase (Fas) and glycerol-3-phosphate acyltransferase (Gpat) Results: There was a significant lipid deposition in the liver of db / db mice. ChREBP protein is diffusely expressed in normal mouse liver tissue and is highly expressed around the central veins and in the portal area. In normal mouse hepatocytes, ChREBP is mainly found in the cytoplasm. However, in the db / db mouse hepatocytes, the level of ChREBP in the nucleus increased by 8.2-fold (P <0.01) compared with the control group. Consistent with this, the expression levels of some of the important ChREBP target genes involved in lipid synthesis in db / db mice, including Acc-1, Fas and Gpat, increased by 2-fold (P <0.05) P <0.05), 4.2 times (P <0.05). CONCLUSIONS: In type 2 diabetic mice, a significant increase in hepatic ChREBP expression and activity activates expression of a number of lipid-related genes, thereby contributing to the formation of fatty liver. This study suggests that ChREBP may be a potential target for the treatment of fatty liver.