羟喜树碱对不同基因型小鼠内脏脂肪组织的影响

发布时间：2018-03-16 19:27

本文选题：内脏脂肪组织　切入点：Wnt/β-catenin信号通路　出处：《山东师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着社会的快速发展，饮食结构不合理、生活不规律等因素使得肥胖已成为世界性的健康问题，肥胖对人的身心健康、工作状态等均能产生许多负面影响，严重损害人们的生活水平，因此，对肥胖及其相关发病机制的研究与当今社会尤为重要。无论是在体还是体外水平上的研究，均发现Wnt/β-catenin信号通路可以抑制成脂分化。肿瘤坏死因子α（tumor necrosis factor-α, TNF-α）可在脂肪组织中发挥与Wnt/β-catenin信号通路类似的作用，即都可以抑制成脂分化中枢调控因子PPARγ、C/EBPα的表达。DKK1可以结合Wnt信号受体LRP5，并与另外一个跨膜受体Kremen结合形成三聚体，引起三聚体的内吞，阻断Wnt信号的传递，而羟喜树碱可以充当DKK1的激动剂，因此许多国内学者利用羟喜树碱来进行阻断Wnt信号通路的研究。在此基础上，我们推测羟喜树碱是否可以阻断小鼠内脏脂肪组织中的Wnt信号通路，进而影响其成脂分化，因此本实验采用四种C57BL/6J品系（WT、TNF-α-/-、Leprdb/db、DT）小鼠来进行羟喜树碱的干预实验，并通过体重、病理形态、基因表达以及蛋白表达四方面的数据来研究羟喜树碱对小鼠内脏脂肪组织的影响。结果如下： 1.随年龄增大，四种基因型小鼠体重均上升，脂肪细胞体积均变大，，且缺失瘦素受体的Leprdb/db与DT小鼠（简称为胖鼠），与不缺失瘦素受体的WT小鼠和TNF-α-/-小鼠（简称瘦鼠）相比变化更明显。TNF-α-/-小鼠直到6w龄时都没有显现出明显的肥胖特征，说明普通饮食条件下并不能造成由于TNF-α缺失而引起的肥胖。而Leprdb/db和DT小鼠早在3W龄时就已开始出现体重增加现象，且DT小鼠的体重增加程度高于Leprdb/db小鼠，二者均向肥胖发展，说明TNF-α的缺失可以增强胖鼠的肥胖程度，反过来证明TNF-α可以增强或协助Wnt/β-catenin信号通路对肥胖的抑制。 2.综合非干预组和对照组小鼠脂肪组织中相关基因的表达，发现胖鼠与瘦鼠相比，其Wnt10b mRNA表达水平较高，而成脂相关因子C/EBPβ、PPARγ、C/EBPα以及AdiponectinmRNA表达水平较低，推测胖鼠体内存在负反馈调节机制，并且想要通过这种方式抑制自身的过度肥胖。 3.在体水平上，注射了羟喜树碱的小鼠，其体重均有所下降，脂肪细胞均有所减小，且羟喜树碱可以下调小鼠内脏脂肪组织Wnt/β-catenin信号通路相关因子Wnt10b、LRP5以及β-catenin的表达，而TNF-α在一定程度上可以加深羟喜树碱的这一作用，此外，羟喜树碱可以提高C/EBPβ而降低PPARγ、C/EBPα的表达量，且这一降低作用大于抑制了Wnt/β-catenin信号通路而引起的促成脂分化作用。综上所述，羟喜树碱对不同基因型小鼠的内脏脂肪组织均可以产生影响，即羟喜树碱在抑制内脏脂肪组织中Wnt/β-catenin信号通路的同时，还抑制了其成脂分化相关基因的表达，抑制其成脂分化，因此可以推断，羟喜树碱对小鼠内脏脂肪组织的影响是通过多条复杂的信号通路，而非单一信号通路。
[Abstract]:With the rapid development of society, the irrational diet structure, irregular life and other factors make obesity has become a worldwide health problem, obesity can have a lot of negative effects on people's physical and mental health, working state, etc. Therefore, the study of obesity and its related pathogenesis is particularly important in today's society. Both in vitro and in vivo, Wnt/ 尾 -catenin signaling pathway has been found to inhibit lipid differentiation. Tumor necrosis factor 伪 -tumor necrosis factor- 伪 (TNF- 伪) may play a similar role to Wnt/ 尾 -catenin signaling pathway in adipose tissue. Both of them could inhibit the expression of PPAR 纬 -C / EBP 伪. DKK1 could bind to Wnt signal receptor LRP5, and combine with another transmembrane receptor Kremen to form trimer, which could induce the endocytosis of trimer and block the transmission of Wnt signal. Hydroxycamptothecin can act as an agonist of DKK1, so many domestic scholars use hydroxycamptothecin to block Wnt signaling pathway. We speculated whether hydroxycamptothecin could block the Wnt signaling pathway in the visceral adipose tissue of mice and then affect its adipogenic differentiation, so we used four C57BL / 6J strains to carry out hydroxycamptothecin intervention in mice. The effects of hydroxycamptothecin on visceral adipose tissue of mice were studied in terms of pathomorphology, gene expression and protein expression. The results were as follows:. 1. With the increase of age, the weight of the four genotypes increased, and the volume of adipocytes increased. The changes of Leprdb/db and DT mice without leptin receptor were more obvious than those of WT mice without leptin receptor deletion and TNF- 伪 -r-r- mice. TNF- 伪 -r-r-mice showed no obvious obesity characteristics until 6 weeks old. The results showed that normal diet could not cause obesity caused by TNF- 伪 deficiency, but Leprdb/db and DT mice had started to gain weight as early as 3W, and the weight gain of DT mice was higher than that of Leprdb/db mice. Both of them developed towards obesity. These results suggest that the absence of TNF- 伪 can enhance obesity in obese rats, which in turn suggests that TNF- 伪 can enhance or assist the inhibition of obesity by Wnt/ 尾 -catenin signaling pathway. 2. By synthesizing the expression of related genes in adipose tissue of non-intervention group and control group, it was found that the expression level of Wnt10b mRNA in fat rats was higher than that in thin mice, while the expression level of C / EBP 尾 -PPAR- 纬 C / EBP 伪 and AdiponectinmRNA in fat mice was lower than that in lean mice. We speculated that there was a negative feedback regulation mechanism in fat rats and wanted to suppress their obesity in this way. 3. In vivo, the mice injected with hydroxycamptothecin decreased their body weight and adipocytes, and hydroxycamptothecin could down-regulate the expression of Wnt/ 尾 -catenin signaling pathway related factors Wnt10bnLRP5 and 尾 -catenin in visceral adipose tissue of mice. To some extent, TNF- 伪 can deepen the effect of hydroxycamptothecin. In addition, hydroxycamptothecin can increase C / EBP 尾 and decrease the expression of PPAR 纬 -EBP 伪, and this decrease is greater than that induced by inhibition of Wnt/ 尾 -catenin signaling pathway. In conclusion, hydroxycamptothecin can affect the visceral adipose tissue of mice with different genotypes, that is, hydroxycamptothecin inhibits Wnt/ 尾 -catenin signaling pathway in visceral adipose tissue and inhibits the expression of genes associated with adipogenic differentiation. It can be inferred that the effect of hydroxycamptothecin on visceral adipose tissue of mice is through several complex signal pathways rather than a single signal pathway.
【学位授予单位】：山东师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R589.2

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