环境内分泌干扰物宫内暴露对子代小鼠肥胖的影响及作用机制研究

发布时间：2018-04-16 14:29

本文选题：DES + MEHP　；参考：《北京协和医学院》2013年硕士论文

【摘要】：流行病学研究表明,在个体发育的窗口期暴露于内分泌干扰物可以导致脂肪形成和肥胖发生。DES(己烯雌酚)是一种类雌激素物质,广泛存在于化妆品和禽蛋中；DEHP(邻苯二甲酸-2-乙基己基酯)是塑料制品工业中普遍使用的一种增塑剂,DEHP—旦被人体摄入便代谢为其单体形式MEHP(邻苯二甲酸-单-2-乙基己基酯),而MEHP更易被人体吸收进而影响人体健康。DES或MEHP在食物链中蓄积并通过多种途径进入人体,进而扰乱机体正常的内分泌系统和代谢通路,破坏机体脂肪组织自稳态的调节,导致肥胖。然而,国内外学术界对DES和MEHP致肥作用的研究开展相对较晚。动物实验、人体实验以及大量的流行病学统计非常缺乏。DES和MEHP诱导脂肪组织形成机制的研究为之甚少,其分子机制尚不明确。因此,我们分别从体内和体外水平评估DES和MEHP在脂肪细胞分化中的作用,探索其潜在的作用机制。在本研究中,油红O染色和3-磷酸甘油脱氢酶(GPDH)活性分析的结果表明：DES可以在体外诱导3T3-L1前脂肪细胞分化成为成熟的脂肪细胞,具体表现为细胞内脂滴聚集增多,3-磷酸甘油脱氢酶(GPDH)活性升高,并且是以剂量依赖的方式进行。DES在体外诱导脂肪细胞增殖分化的分子机制是通过细胞雌激素受体作用于细胞,通过调节PPARγ、促进与脂肪细胞分化、脂肪形成相关的基因的表达从而促进脂肪形成；体内也遵循同样的机制。围产期宫内暴露低剂量DES可以使成年(2个月)子代雌性小鼠的体重、肝重和脂肪垫重量显著增加,而且甘油三酯和血糖水平也显著升高。油红O染色结果显示1-100μM MEHP可以诱导前脂肪细胞系3T3-L1分化为成熟的脂肪细胞,表现为细胞内脂滴聚集增多,3-磷酸甘油脱氢酶(GPDH)活性升高；并且随诱导浓度增加,细胞分化程度升高。分子水平检测显示,MEHP在诱导脂肪细胞分化过程中激活PPARy及其下游靶基因aP2和LPL的表达。进一步体内证据表明,低剂量(0.05mg/kg体重)MEHP明显诱导雄性子代小鼠成年后肥胖的发生,具体表现为：体重和体脂含量增加,血清总胆固醇、甘油三酯和血糖水平的异常上升。分子水平检测表明,MEHP宫内暴露激活体内PPARy及其靶基因aP2, FAS和LPL的表达上调,而对促进脂肪酸氧化的PPARa无诱导效应。提示邻苯二甲酸酯MEHP分别从体内、外水平诱导脂肪细胞分化进而促进肥胖的发生。综上,我们的研究结果表明宫内暴露于低剂量的DES或MEHP通过激活PPARy信号通路,进而诱导脂肪细胞分化,导致肥胖发生。因此,DES或MEHP可能作为潜在的化学诱导因子诱发肥胖及相关疾病发生。
[Abstract]:Epidemiological studies have shown that exposure to endocrine disruptors during the ontogeny window can lead to fat formation and obesity. DES (diethylstilbestrol) is an estrogen substance.DEHP- (phthalic acid-2-ethylhexyl ester) is a kind of plasticizer widely used in plastics industry, which is widely used in cosmetics and eggs. DEHP- (phthalic acid-mono-2-ethylhexyl) is metabolized by human body and then metabolized as its monomer form (phthalic acid-mono-2-ethylphthalate).Hexyl ester, and MEHP is more easily absorbed by the human body and then affects human health. Des or MEHP accumulates in the food chain and enters the human body through a variety of channels.Thus disrupting the normal endocrine system and metabolic pathway, disrupting the self-stable regulation of adipose tissue, resulting in obesity.However, the research on the effect of DES and MEHP on the effect of fertilization is relatively late in academic circles at home and abroad.Animal experiments, human experiments and a large number of epidemiological statistics lack of research on the mechanism of adipose tissue formation induced by .DES and MEHP, and its molecular mechanism is still unclear.Therefore, we evaluate the role of DES and MEHP in adipocyte differentiation in vivo and in vitro, and explore its potential mechanism.The results of oil red O staining and glycerol 3-phosphate dehydrogenase (GPDH) activity analysis showed that 3T3-L1 preadipocytes could differentiate into mature adipocytes in vitro.The results showed that the increase of lipid droplet aggregation in cells increased the activity of glycerol 3-phosphate dehydrogenase (GPDH), and the molecular mechanism of inducing adipocyte proliferation and differentiation in vitro by .DES in a dose-dependent manner was through the action of cellular estrogen receptor on the cells.By regulating PPAR 纬, the expression of genes related to adipocyte differentiation and adipogenesis is promoted, and the same mechanism is followed in vivo.Low dose DES exposure during perinatal period could significantly increase the body weight, liver weight and fat pad weight of adult (2 months) female mice, as well as the level of triglyceride and blood sugar.The results of oil red O staining showed that 1-100 渭 M MEHP could induce preadipose cell line 3T3-L1 to differentiate into mature adipocytes, and the activity of glycerol 3-phosphate dehydrogenase (GPDH) increased with the increase of lipid droplets.The degree of cell differentiation increased.Molecular level detection showed that MEHP activated the expression of PPARy and its downstream target genes aP2 and LPL during adipocyte differentiation.Further evidence in vivo showed that MEHP at a low dose of 0.05 mg / kg significantly induced obesity in male offspring after adulthood, as follows: the increase of body weight and body fat content, the abnormal increase of serum total cholesterol, triglyceride and blood glucose levels.Molecular level detection showed that the expression of PPARy and its target genes aP2, FAS and LPL were up-regulated by intrauterine exposure to MEHP, but not on PPARa, which promoted the oxidation of fatty acids.The results suggest that phthalate MEHP induces adipocyte differentiation in vivo and in vitro and promotes the development of obesity.In conclusion, our results suggest that intrauterine exposure to low-dose DES or MEHP induces adipocyte differentiation by activating the PPARy signaling pathway, leading to obesity.Therefore, des or MEHP may be a potential chemoinducer to induce obesity and related diseases.
【学位授予单位】：北京协和医学院
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R114

【参考文献】