模拟代谢性内毒素血症对肝损伤小鼠肝组织TLR4信号通路的影响  

Influence of mimic metabolic endotoxemia on hepatic histology and TLR4 signaling pathway in mice

作　　者：徐正婕[1] 李楠[2] 何崇信 范建高[1] 

机构地区：[1]上海交通大学医学院附属新华医院消化科,上海市200092 [2]浙江医院消化科

出　　处：《实用肝脏病杂志》2014年第6期615-618,共4页Journal of Practical Hepatology

基　　金：国家重点基础研究发展计划973项目(2012CB517501);国家自然科学基金项目(81070322;81270491);上海市科学技术委员会科研基金(09140903500;10411956300);上海市卫生局新百人计划项目(XBR2011007);王宝恩肝纤维化基金项目20110006

摘　　要：目的观察持续4 w的模拟代谢性内毒素血症对小鼠肝脏组织病理和4型Toll样受体(TLR4)信号通路的影响。方法将30只雄性C57BL/6J小鼠随机分为正常组(n=10)和内毒素组(n=10),均予以普通饲料喂养,和高脂组(n=10),予以高脂饲料喂养。内毒素组小鼠同时经腹部皮下植入的微泵注入内毒素300μg·kg-1·d-1,连续4 w,正常组小鼠皮下微泵持续注入生理盐水作为对照。4 w后测定小鼠血清内毒素水平,对肝组织切片行HE染色后进行非酒精性脂肪性肝病评分(NAS),采样Real time PCR法测定小鼠肝组织TLR4及其下游的My D88和TRIF-related adaptor molecule(TRAM)m RNA水平。结果内毒素组小鼠血清内毒素水平(0.62±0.04 EU/ml)显著高于正常组(0.50±0.06 EU/ml,P<0.05)和高脂组(0.49±0.05 EU/ml,P<0.05);内毒素组小鼠肝组织主要表现为单纯性脂肪变性,NAS积分为(2.30±0.49),高脂组小鼠肝组织炎症较明显,NAS积分为(4.20±1.61),显著高于内毒素组(P<0.05);与正常组相比,内毒素组小鼠肝组织TLR4 m RNA水平上调5.12倍(P<0.01),TRAM m RNA水平上调3.46倍(P<0.01),而My D88 m RNA水平与正常组比,无显著差别。结论持续4 w的模拟代谢性内毒素血症可诱导小鼠肝脏单纯性脂肪变性,TLR4 m RNA和TRAM m RNA水平上调,而My D88 m RNA水平无显著变化。Objective To observe the influence of 4-week mimic metabolic endotoxemia on hepatic histology and Toll-like receptor 4 （TLR4） signaling pathway in mice. Methods Thirty male C57BL/6J mice were randomly divided into normal （n=10） and endotoxin （n=10） groups,fed with normal diet,and high-fat （n=10） group,fed with high-fat diet. The mice in endotoxin group were implanted with subcutaneous osmotic minipump to infuse endotoxin at 300 μg·kg-1·d-1 for 4 weeks. The mice in normal group were implanted with minipump filled with saline as control. At the end of the 4th week,the serum endotoxin level were detected. NAFLD activity score （NAS） of liver tissue was evaluated. The mRNA levels of hepatic TLR4,MyD88 and TRAM were detected by real time PCR. Results Serum endotoxin level in endotoxin group [（0.62±0.04） EU/ml] was significantly higher than that in normal group [（0.50±0.06） EU/ml,P〈0.05] and in high-fat group [（0.49±0.05） EU/ml,P〈0.05];The dominant histology change of liver in endotoxin mice was simple steatosis and the NAS score was （2.30 ±0.49）, while the mice in high-fat group had more severe hepatic inflammation and the NAS score was（4.20±1.61）,which was significantly higher than that in the endotoxin group（P〈0.05）;The TLR4 mRNA level in endotoxin group was 5.12 times higher （P〈0.01） and TRAM mRNA level was 3.46 times higher （P〈0.01） as compared with in normal group, but the MyD88 mRNA levels in the three groups had no significant difference. Conclusion Four-week mimic metabolic endotoxemia induces hepatic steatosis with increased levels of hepatic TLR4 and TRAM mRNA, but has no effect on the hepatic MyD88 mRNA.

关 键 词：非酒精性脂肪性肝病 代谢性内毒素血症 高脂饮食 4型Toll样受体 小鼠 

分 类 号：R575.5[医药卫生—消化系统]