本文選題：內臟脂肪組織　切入點：Wnt/β-catenin信號通路　出處：《山東師范大學》2015年碩士論文　論文類型：學位論文

【摘要】：隨著社會的快速發(fā)展，飲食結構不合理、生活不規(guī)律等因素使得肥胖已成為世界性的健康問題，肥胖對人的身心健康、工作狀態(tài)等均能產生許多負面影響，嚴重損害人們的生活水平，因此，對肥胖及其相關發(fā)病機制的研究與當今社會尤為重要。 無論是在體還是體外水平上的研究，均發(fā)現(xiàn)Wnt/β-catenin信號通路可以抑制成脂分化。腫瘤壞死因子α（tumor necrosis factor-α, TNF-α）可在脂肪組織中發(fā)揮與Wnt/β-catenin信號通路類似的作用，即都可以抑制成脂分化中樞調控因子PPARγ、C/EBPα的表達。DKK1可以結合Wnt信號受體LRP5，并與另外一個跨膜受體Kremen結合形成三聚體，引起三聚體的內吞，阻斷Wnt信號的傳遞，而羥喜樹堿可以充當DKK1的激動劑，因此許多國內學者利用羥喜樹堿來進行阻斷Wnt信號通路的研究。在此基礎上，我們推測羥喜樹堿是否可以阻斷小鼠內臟脂肪組織中的Wnt信號通路，進而影響其成脂分化，因此本實驗采用四種C57BL/6J品系（WT、TNF-α-/-、Leprdb/db、DT）小鼠來進行羥喜樹堿的干預實驗，并通過體重、病理形態(tài)、基因表達以及蛋白表達四方面的數(shù)據(jù)來研究羥喜樹堿對小鼠內臟脂肪組織的影響。結果如下： 1.隨年齡增大，四種基因型小鼠體重均上升，脂肪細胞體積均變大，，且缺失瘦素受體的Leprdb/db與DT小鼠（簡稱為胖鼠），與不缺失瘦素受體的WT小鼠和TNF-α-/-小鼠（簡稱瘦鼠）相比變化更明顯。TNF-α-/-小鼠直到6w齡時都沒有顯現(xiàn)出明顯的肥胖特征，說明普通飲食條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齡時就已開始出現(xiàn)體重增加現(xiàn)象，且DT小鼠的體重增加程度高于Leprdb/db小鼠，二者均向肥胖發(fā)展，說明TNF-α的缺失可以增強胖鼠的肥胖程度，反過來證明TNF-α可以增強或協(xié)助Wnt/β-catenin信號通路對肥胖的抑制。 2.綜合非干預組和對照組小鼠脂肪組織中相關基因的表達，發(fā)現(xiàn)胖鼠與瘦鼠相比，其Wnt10b mRNA表達水平較高，而成脂相關因子C/EBPβ、PPARγ、C/EBPα以及AdiponectinmRNA表達水平較低，推測胖鼠體內存在負反饋調節(jié)機制，并且想要通過這種方式抑制自身的過度肥胖。 3.在體水平上，注射了羥喜樹堿的小鼠，其體重均有所下降，脂肪細胞均有所減小，且羥喜樹堿可以下調小鼠內臟脂肪組織Wnt/β-catenin信號通路相關因子Wnt10b、LRP5以及β-catenin的表達，而TNF-α在一定程度上可以加深羥喜樹堿的這一作用，此外，羥喜樹堿可以提高C/EBPβ而降低PPARγ、C/EBPα的表達量，且這一降低作用大于抑制了Wnt/β-catenin信號通路而引起的促成脂分化作用。 綜上所述，羥喜樹堿對不同基因型小鼠的內臟脂肪組織均可以產生影響，即羥喜樹堿在抑制內臟脂肪組織中Wnt/β-catenin信號通路的同時，還抑制了其成脂分化相關基因的表達，抑制其成脂分化，因此可以推斷，羥喜樹堿對小鼠內臟脂肪組織的影響是通過多條復雜的信號通路，而非單一信號通路。
[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 偽 -tumor necrosis factor- 偽 (TNF- 偽) may play a similar role to Wnt/ 尾 -catenin signaling pathway in adipose tissue. Both of them could inhibit the expression of PPAR 緯 -C / EBP 偽. 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- 偽 -r-r- mice. TNF- 偽 -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- 偽 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- 偽 can enhance obesity in obese rats, which in turn suggests that TNF- 偽 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- 緯 C / EBP 偽 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- 偽 can deepen the effect of hydroxycamptothecin. In addition, hydroxycamptothecin can increase C / EBP 尾 and decrease the expression of PPAR 緯 -EBP 偽, 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.
【學位授予單位】：山東師范大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：R589.2

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