胆汁内外引流术对梗阻性黄疸小鼠肠道FXR及TLR4表达的影响

Effects of internal and external biliary drainage on intestinal FXR and TLR4 expression in mice with obstructive jaundice

目的通过小鼠梗黄及胆汁内外引流模型,观察小鼠肠黏膜胆汁酸核受体法尼酯衍生物X受体(Farnesoid X receptor,FXR)和病原模式识别受体Toll样受体4(Toll-like receptor 4,TLR4)的表达变化并探讨两者之间的相互作用。方法采用成年雄性昆明小鼠60只随机分为四组,即梗黄组(OJ组)、胆汁外引流组(ED组)、胆汁内引流组(ID组)和假手术组(SH组),每组15只。利用蛋白质印迹分析(Western blotting)和实时荧光定量PCR(qRT-PCR)法检测回肠黏膜FXR与TLR4蛋白及其mRNA的表达。此外,取40只小鼠随机分为OJ、ED、ID和SH四组,每组10只,各组中再用FXR激动剂GW4064(n=5)灌胃干预,羧甲基纤维素钠CMC-Na(n=5)作为对照。结果小鼠胆道梗阻后,肠黏膜FXR蛋白及其mRNA表达较SH组明显升高,肠黏膜TLR4蛋白及其mRNA表达较SH组明显下降。胆汁外引流术后,FXR蛋白表达较OJ组明显下降而其mRNA表达升高,TLR4蛋白及其mRNA表达明显升高。胆汁内引流术后,FXR蛋白及其mRNA表达较OJ组下降,TLR4蛋白及其mRNA表达明显上升,效果均好于外引流(P<0.05)。安慰剂灌胃和上述未行灌胃的小鼠的TLR4表达趋势基本一致,而利用FXR激动剂灌胃后,四组小鼠TLR4表达差异消失(P>0.05)。结论小鼠梗黄形成后,肠道FXR升高,TLR4下降,胆汁内引流和外引流均可逆转这些改变,但内引流效果好于外引流。肠道内胆汁酸是引起这些变化的关键。

Objective To study the expression of intestinal FXR and TLR4 in mice with obstructive jaundice(OJ)and its relief by internal biliary drainage(ID)and external biliary drainage(ED)and to explore interaction mechanism between FXR and TLR4.Methods Sixty male adult Kunming mice were randomly assigned to 4 groups:OJ,ED,ID,sham operation(SH)(15 mice in each group).Western blotting and qRT-PCR were used to detect the expression of protein and mRNA of FXR and TLR4 in intestinal mucosa.Moreover,another 40 mice were randomly averaged to 4 groups:OJ,ED,ID,SH(n=10).Food gavage with FXR agonist-GW4064 was given in 5 mice and vehicle-CMC-Na in another 5 mice in each group.Results After biliary obstruction,the expressions of protein and mRNA of FXR were significantly increased compared with those in SH group.The expressions of protein and mRNA of TLR4 were significantly decreased compared with those in SH group.After ED,compared with those in OJ group,the expressionss of protein of FXR was decreased while mRNA was incresed and the expressions of protein and mRNA of TLR4 were increased.After ID,the expressions of protein and mRNA of FXR were significantly decreased compared with those in OJ group and were better than those in ED group.And the expressions of protein and mRNA of TLR4 were significantly increased compared with those in OJ group and were better than those in ED group(P<0.05).The trend of TLR4 expression was almost the same between vehicle group and no gavage group.After gavage with FXR agonist,the differences of TLR4 expression of 4 groups disappeared(P>0.05).Conclusion The expression of intestinal FXR is increased while TLR4 is decreased in mice with OJ.These changes could be reversed by relief of jaundice,but internal biliary drainage is better than external biliary drainage.Bile acids in the intestine play a key role underlying the mechanism of the changes.