早期肠内营养对危重症导致肝脏“二次打击”的保护作用

Effect of the early enteral nutrition on liver protection from the ＂second hit＂ cauesd by the critical diseases

目的探讨早期肠内营养对危重症导致的肝脏“二次打击”保护作用的机制及最佳营养支持时间。方法建立大鼠失血性休克内毒素腹腔注射的“二次打击”及肠内肠外营养模型。根据营养方式分为3个大组，分别为单纯肠内营养组（EN组）、单纯肠外营养组（PN组）、混合营养组（EPN组）。在EN组和EPN组分别于术后0，6，12，24h给予肠内和（或）肠外营养液，又分别分为ENl—4组和EPNl—4组；PN组只在术后12h给予肠外营养液。每组均在术后给予营养支持5d，分别在指定时点采血并获取肝和小肠组织进行定向实验。分别观察肝功能血清学指标、肠道细菌内毒素移位情况和内毒素受体-TLR4蛋白的表达。结果EN组、EPN组与PN组有显著差异（P〈0．05）；EPN组与单纯EN无差异（P〉0．05）；EN3和EPN3组各项指标最优。结论早期肠内营养支持有效的减轻了“二次打击”给肝脏带来的损伤；EN优于PN支持方式；术后6hEN支持是安全的，术后12h支持是最佳营养应用时机；只要在适当时机给予EN就有效，营养支持效果与EN所提供的热量氮量在全部营养液中所占比例无关。

Objective To study the mechanism of the effect of the early enteral nutrition on liver protection from the ＂second hit＂ injury caused by the critical diseases. Methods The model of ＂second hit＂ caused by hemorrhagic shoek-lipopotysaceharide injected via intraperitoneal and enteral or parenteral nutrition using Wistar rats was established. The rats were divided into three groups including enteral nutrition group （Group EN）, parenteral nutrition group （Group PN） and compounded nutrition group （Group EPN）. Enteral ＆ parenteral nutrition were supported at 0, 6, 12, 24h to Group EN ＆ Group EPN, which further sampled as ENl-4＆ EPNl-4 Sub-groups; parenteral nutrition was infused 12 h after operation in group PN. Nutrition had been supplied for 5 consecutive days for each of group. Blood was taken on 1^st , 3^rd＆ 5^th day for every group; the rats were sacrified on 5^th day and the liver ＆ small intestine had been obtained for directional examination. Hepatic serology indicators were inspected via auto-biochemistry analyzing equipment; the bacteria translocation was inspected hy means of bacterial culture and the LPS determination; the high expression of TLR4 protein was detected via immunohistochemistry. Results Judged by the biochemistrial, bacterial, pathologial indicators, Group EN ＆ EPN show significant difference from Group PN （P〈0.05）, no significant difference between EN ＆ EPN （P〉0.05）. EN3 ＆ EPN3 have the best indicators among the nutritional groups. ConcLusion EEN has been effectively reduced the damage to liver under ＂second hit＂ injury. Providing nutrition at 6^th hour post-operation is safety, the 12^th hour post-operation shall be the most effective choice for EN supplying. Only EN is effective, the radio of calorie ＆ nitrogen supplied by EN to all nutrition supplied ways has no connection with the clinical effect, which explains quantity does not impact the result.