小肠屏障功能监测的实验研究

目的 通过对创伤后小肠屏障功能几种监测方法的对比分析，试图找到一种适合临床推广的快速敏感的监测方法。方法 北京地区雄性成年山羊32只，随机分为创伤性失血性休克组（H组，n＝6），创伤内毒素血症组（E组，n＝6）和创伤失血再灌注复合内毒素组（M组，n＝20），模拟临床创伤、缺血再灌注（I／R）、感染脓毒症的实验模型。同时监测二胺氧化酶（DAO）、肠粘膜下pH（(pHi)和尿乳果糖／甘露醇比值，并参照血浆内毒素（LPS）、TNF和病理形态学结果进行对比分析。结果 创伤和失血性休克后当日血浆DAO活性可呈一过性升高，M组在输入内毒素后再度升高呈双峰型，H组术后第一天开始DAO渐趋下降，E组自手术当日开始逐渐升高。M组L／M较E组增显著；创伤、休克末和输内毒素后小肠pHi持续降低。血浆DAO的变化与L／M和肠粘膜pHi的变化呈高度相关（r=0.951和－0．553，P＜0．01－0．05），三种肠功能指标与 浆LPS和TNF的变化高度相关，并与病理形态学变化相一致。结论 创伤缺血再灌流，单纯输内毒素均可导致肠屏障功能损伤，这种损伤是短暂和可逆的；创伤缺血再灌注流复合内毒素血症对肠屏障功能的损伤程度明显加重；DAO活性、L／M和肠pHi均能敏感地反映出创伤肠屏障功能损伤程度和逆转情况，但以DAO法更快速敏感，且能反应出肠上皮修复情况，又不平加病人痛苦，适于临床推广。

An experimental study on monitoring of barrier function of small intestine

Objective　To establish a rapid and sensitive method for clinical monitoring of barrier function of small intestine in patients with trauma.Methods　Thirty-two male goats were randomly divided into 3 groups which were trauma-hemorrhagic shock group(group H,n=6),trauma-endotoxemia group(group E,n=6) and trauma-hemorrhagic shock plus endotoxemia group(group M,n=20 ). The animal model proved to be a good simulation of trauma, bowel ischemia /reperfusion and sepsis in patients. Plasma DAO , intestinal mucosa pH (pHi) and the ratio of lactulose/mannitol (L/M) were determined, and comparative analysis was performed in accordance with plasma LPS , TNFα and morphological alteration.Results　The activity of DAO increased greatly at the end of shock stage in group H and peaked twice in group M. L/M ratio was significantly higher in group M than that in group E.The pHi decreased progressively after LPS infusion. The change in plasma level of DAO was highly correlated with that of L/M and pHi, and was in accordance with the morphological changes. The change in plasma level of DAO, L/M and pHi was highly correlated with that of LPS and TNFα.Conclusion　Both traumatic ischemia-reperfusion injury and LPS infusion will lead to temporal and reversible impairment of gut barrier function. The status of gut barrier function can be reflected by DAO, L/M and pHi. Our investigation indicates that DAO is the most sensitive parameter for the prediction of gut barrier function and thus is clinically valuable.