酒精性肝炎小鼠肝肠组织变化与内毒素血症的关系探讨

Observation of intestinal hyperpermeability and endotoxemia in mice with alcoholic steatohepatitis

目的酒精性肝病常伴发肠源性内毒素血症,但两者孰因孰果尚不明确。本研究的目的是探讨肠源性内毒素血症与酒精性肝病的关系。方法 20只C57BL/6小鼠被随机分为对照组和模型组,采用饲喂Lieber-Decarli无酒精和含酒精液体法制备酒精性肝炎模型。6周后取小鼠肝脏和结肠组织进行病理学观察;采用酶联免疫吸附法检测血清内毒素、二胺氧化酶和D乳酸含量;采用高效液相色谱法分析尿中乳果糖和甘露醇含量比值,以动态观察小鼠肠道通透性的变化。结果模型组动物肝细胞明显脂肪变,说明模型制备成功;模型组动物结肠粘膜变薄,萎缩,肠上皮细胞脱落,病理学评分（3.41±0.59）与对照组（2.36±0.43）比,差异有统计学意义（P=0.04）;模型组和对照组动物血清内毒素水平分别为0.40±0.07Eu/L和0.14±0.03Eu/L（P=0.02）,二胺氧化酶分别为4.17±0.88 U/mL和2.09±0.39U/mL（P=0.03）,D乳酸分别为8.53±1.10mg/L和6.58±1.00mg/L（P=0.04）,差异均有统计学意义;模型组小鼠1~6周末尿乳果糖/甘露醇（L/M值）排泄率分别是2.28±0.33（P〉0.05）、2.55±0.40、2.49±0.18、2.51±0.55、2.46±0.59和2.59±0.44,对照组则分别是2.16±0.30、2.34±0.33、2.27±0.24、2.01±0.27、2.24±0.26和2.17±0.31,后5周两组比,均有显著性差异（P〈0.05）。结论肠道通透性的增加早于肝脏损伤,肠道通透性增加引起的内毒素血症是酒精性肝炎的关键诱发因素。

Objective The purpose of this study was to investigate intestinal hyperpermeability and endotoxemia in mice with alcoholic steatohepatitis.Methods Twenty male C57BL/6 wildtype mice were randomly divided into alcohol and control group（n=10）.Mice were fed separately an alcohol or isocaloric liquid diet for 6 wk,and serum endotoxin,D-lactic acid and diamine oxidase（DAO）were detected by enzyme-linked immunosorbent assay,and the histological observation of intestine and liver tissues were assessed.Results The steatohepatitis in mice was successfully established in modet group,and the histological scores of colon in alcohol group（3.41±0.59）was significantly higher than tha（t2.36±0.43,P0.01）in control group;serum concentration of endotoxin in alcohol group and control group were 0.40±0.07Eu/L and 0.14±0.03Eu/L,D-lactic acid was 8.53±1.10mg/L and 6.58±1.00mg/L,and DAO was 4.17 ±0.88mg/L and 2.09 ±0.39mg/L,respectively（P 0.05）;Urine lactulose/mannitol ratios at the end of week one to six in alcohol group were 2.28±0.33（P0.05）,2.55±0.40,2.49±0.18,2.51±0.55,2.46±0.59 and 2.59±0.44,while those in control were 2.16±0.30,2.34±0.33,2.27±0.24,2.01±0.27,2.24±0.26 and 2.17±0.31,respectively（P0.05）.Conclusion Alcohol induces gut leakiness and endotoximia,which might be related to the pathogenesis of steatohepatitis in mice.