NAFLD家兔肠道菌群与肠黏膜Toll样受体4的关系

Association between intestinal flora and Toll-like receptor 4 in rabbits with nonalcoholic fatty liver disease

目的:研究非酒精性脂肪肝(non-alcoholic fatty liver disease,NAFLD)家兔肠道菌群的改变,并分析菌群与肠黏膜Toll样受体4(Toll-like receptor 4,TLR4)间的关系.方法:14只♂新西兰家兔随机分成对照组及模型组,对照组给以普通饲料,模型组给以高脂饲料,喂养12 wk后处死.取肝脏组织行HE染色观察肝脏,取回肠组织行免疫组织化学观察肠黏膜TLR4的定位及表达,取肠内容物行实时荧光定量-聚合酶链反应(RT-PCR)检测肠内容物中大肠杆菌、乳酸杆菌、双歧杆菌拷贝数的变化.用多元线性回归分析肠道菌群的改变对肠黏膜TLR4表达的影响.结果:与对照组相比,模型组家兔肠腔中大肠杆菌数量增多(t=-3.492,P=0.008),而乳酸杆菌(t=-1.848,P=0.089)、双歧杆菌(t=-1.059,P=0.311)数量无明显改变,肠黏膜TLR4表达升高(t=-4.089,P=0.002),回归分析显示大肠杆菌、双歧杆菌对肠黏膜TLR4表达有明显影响(R2=0.598,F=8.167,P=0.007);双歧杆菌与TLR4呈负相关(标准化=-0.475),大肠杆菌与TLR4呈正相关(标准化=0.554).而乳酸杆菌与TLR4无明显相关性.结论:NAFLD家兔存在肠道菌群失调,且对肠道TLR4的表达有显著影响.

AIM： To explore the alterations in intestinal flora and analyze the association of intestinal flora with intestinal mucosa TolMike receptor 4 （TLR4） in rabbits with nonalcoholic fatty liver disease （NAFLD）. METHODS： Fourteen male New Zealand rab-bits were randomly divided into two groups： a control group and a NAFLD group. The con-trol group was given a normal diet while the NAFLD group was given a high fat diet. The rabbits were sacrificed 12 wk later. Immunohis- tochemical staining was performed to observe the location and expression of TLR4 in ileal tis- sue. Real-time fluorescence quantitative poly-merase chain reaction was used to detect the number of Escherichia coli （E. coli）, bifidobacteria,and lactobacilli in the ileum. Stepwise multiple linear regression was performed to analyze the relationship between intestinal flora and TLR4. RESULTS： Compared with the control group, the number of E. coli in the NAFLD group in- creased significantly （t = -3.492, P = 0.008）, but the number of bifidobacteria （t = -1.059, P = 0.311） and lactobacilli （t = -1.848, P = 0.089） had no sig- nificant differences between the two groups. The expression of TLR4 was significantly increased （t = -4.089, P 〈 0.01） in the NAFLD group. Regres-sion analysis revealed that E. coli and bifidobac-teria were closely related to TLR4 expression （R^2 = 0.598, F = 8.167, P = 0.007）. Although the number of E. coli had a positive correlation with TLR4 expression （standardized beta = 0.554） and that of bifidobacteria had a negative correla-tion with TLR4 expression （standardized beta = -0.475）, the number of lactobacilli had no signifi-cant correlation with TLR4 expression. CONCLUSION： Intestinal flora imbalance was observed in rabbits with NAFLD, and it had an obvious influence on the expression of TLR4.