探讨肝硬化大鼠肝大部分切除术后肠道细菌移位的机制。

4周龄SPF级健康雄性SD大鼠40只，平均体重（90±10） g，建立肝硬化大鼠模型后按随机数字表法随机分为假手术（SO）组和肝大部分切除术（PH）组，每组各20只。SO组仅剪断肝周围韧带后关腹；PH组行改良大鼠肝大部分切除术，切除肝左内、外叶和肝中叶，切除量约2/3。每组大鼠各取10只于术后24 h测量门静脉压力，剩余10只于术后24 h检测血浆D-乳酸、内毒素水平，肠系膜淋巴结细菌含量，小肠黏膜组织学改变，小肠组织紧密连接蛋白ZO-1、Claudin-1含量，小肠组织肿瘤坏死因子（TNF）-α、干扰素（IFN）-γ、肌球蛋白轻链激酶（MLCK）表达水平，粪便菌群变化。两组正态分布的实验数据比较采用t检验；两组小肠黏膜的Chiu's评分采用M（Q₂₅，Q₇₅）表示，比较采用秩和检验；两组率的比较采用χ²检验。

SO组门静脉压力为（15.4±1.1）cmH₂O（1 cmH₂O=0.098 kPa），PH组为（22.9±0.7）cmH₂O，PH组门静脉压力明显高于SO组（t= -11.15，P<0.05）。SO组血浆内毒素水平为（48.6±2.4）EU/ml，PH组为（52.6±2.3）EU/ml，PH组血浆内毒素水平明显高于SO组（t= -3.31，P<0.05）。PH组肠系膜淋巴结细菌含量为SO组的（162±55）%，PH组肠系膜淋巴结细菌含量较SO组明显增加（t=-2.22，P<0.05）。SO组血浆D-乳酸水平为（37.4±2.8）mg/L，PH组为（60.6±5.0）mg/L，PH组血浆D-乳酸水平明显高于SO组（t= -9.70，P<0.05）。SO组小肠黏膜的Chiu's评分中位数为1（1，2）分，PH组为4（3，4）分，PH组小肠黏膜的Chiu's评分明显高于SO组（Z= -3.52，P<0.05）。SO组小肠组织紧密连接蛋白ZO-1、Claudin-1含量分别为0.70±0.09、0.62±0.10，PH组分别为0.50±0.14、0.33±0.13，PH组小肠组织紧密连接蛋白ZO-1、Claudin-1含量明显低于SO组（t=2.78，2.98；P<0.05）。SO组小肠组织TNF-α、IFN-γ、MLCK的强阳性率分别为20%（2/10）、10%（1/10）、20%（2/10），PH组分别为50%（5/10）、40%（4/10）、70%（7/10），PH组小肠组织TNF-α、IFN-γ、MLCK的强阳性率明显高于SO组（χ²=4.87，8.37，5.01；P<0.05）。PH组粪便大肠埃希菌、类杆菌、梭杆菌、肺炎克雷伯菌、双歧杆菌含量为SO组的（288±74）%、（185±48）%、（278±82）%、（551±96）%、（43±7）%，PH组粪便中大肠埃希菌、类杆菌、梭杆菌、肺炎克雷伯菌含量明显多于SO组，而双歧杆菌含量明显少于SO组（t=2.49，3.68，2.24，5.50，-3.89；P<0.05）。

肝硬化大鼠肝大部分切除术后肠道细菌移位的机制可能与肠道机械屏障和细菌屏障受损有关。术后降低门静脉压力和炎症因子水平、纠正肠道菌群失调可能为减少肠道细菌移位的有效方法。

To investigate the mechanism of intestinal bacterial translocation in rats with liver cirrhosis after partial hepatectomy.

Forty healthy spelific pathogen free male Sprague-Dawley (SD) rats [4 weeks old, average weight: (90±10)g] were randomly divided into sham operation group (SO group) and partial hepatectomy group (PH group) with 20 rats in each group after liver cirrhosis model was established. Rats in SO group underwent separation of perihepatic ligaments then the abdomen was closed. Rats in PH group underwent modified partial hepatectomy including resection of left medial lobe, lateral lobe and middle lobe. The volume of resected liver was about 2/3. Portal pressure was tested in 10 rats from each group 24 h after operation. The levels of plasma D-lactate, endotoxin, content of bacteria in mesenteric lymph nodes, histological change of small intestinal mucosa, contents of tight junction protein ZO-1 and Claudin-1 of small intestinal tissue, expressions of tumor necrosis factor (TNF)-α, interferon (IFN)- γ, myosin light chain kinase (MLCK) of small intestinal tissues, changes of fecal flora were tested in the other 10 rats of each group 24 h after operation. The experimental data with normal distribution in 2 groups were compared using t test. The Chiu's scores of small intestinal mucosa in 2 groups were expressed in M(Q₂₅, Q₇₅) and were compared using rank sum test. The comparison of rates in 2 groups was conducted using Chi-square test.

The portal pressure in PH group [(22.9±0.7)cmH₂O] (1 cmH₂O=0.098 kPa) was significantly higher than that in SO group [(15.4±1.1)cmH₂O] (t= -11.15, P<0.05). The level of plasma endotoxin in PH group [(52.6±2.3)EU/ml] increased obviously, compared with that in SO group [(48.6±2.4)EU/ml] (t= -3.31, P<0.05) . The content of bacteria in mesenteric lymph nodes in PH group was (162±55)% of that in SO group, which was significantly higher than that in SO group (t= -2.22, P<0.05). The level of plasma D-lactate was (60.6±5.0)mg/L in PH group, which was significantly higher than that in SO group [(37.4±2.8)mg/L] (t= -9.70, P<0.05). The median of Chiu's score of small intestinal mucosa was 4(3, 4) in PH group, which was significantly higher than that in SO group [1(1, 2)] (Z= -3.52, P<0.05). The contents of tight junction protein ZO-1 and Claudin-1 of small intestinal tissue in PH group were 0.50±0.14, 0.33±0.13 respectively, which were significantly lower than those in SO group (0.70±0.09, 0.62±0.10) (t=2.78, 2.98; P<0.05). The strong positive expression rates of TNF-α, IFN-γ, MLCK were 50%(5/10), 40%(4/10), 70%(7/10) in PH group, which were significantly higher than those in SO group [20%(2/10), 10%(1/10), 20%(2/10)] (χ²=4.87, 8.37, 5.01; P<0.05). The contents of fecal Escherichia coli, Bacteroides, Fusobacterium, Klebsiella pneumoniae, Bifidobacteria in PH group were (288±74)%, (185±48)%, (278±82)%, (551±96)%, (43±7)% of those in SO group. The contents of fecal Escherichia coli, Bacteroides, Fusobacterium, Klebsiella pneumoniae in PH group were significantly higher than those in SO group, while the content of Bifidobacteria was significantly lower (t=2.49, 3.68, 2.24, 5.50, -3.89; P<0.05).

The mechanism of intestinal bacterial translocation in rats with liver cirrhosis after partial hepatectomy may be associated with the damage of intestinal mechanical barrier and bacterial barrier. Reducing the portal pressure and level of inflammatory factor, and correcting the intestinal bacterial imbalance may be effective methods for reducing intestinal bacterial translocation.