大鼠急性肠缺血后血浆D-乳酸的变化及其与肠粘膜损害的关系

目的观察肠缺血再灌注时门、体循环 D-乳酸的动态变化及其与肠粘膜损害的相关性。方法采用大鼠肠系膜上动脉阻断75分钟后松夹进行重灌注的模型,分别于术前,阻断末,松夹后0.5,2,6小时活杀动物,观察门静脉和体循环 D-乳酸水平、血浆内毒素含量及小肠病理形态学改变。结果肠缺血75分钟后大鼠门静脉 D-乳酸水平较伤前值显著上升(P<0.05),再灌注后呈进一步持续升高趋势。外周血 D-乳酸的改变与门脉血基本一致,各时相点与门脉血含量相比差异无显著意义(P>0.05)。相关分析结果显示,门静脉血浆 D-乳酸含量与肠粘膜损伤评分值呈显著正相关(r=0.415,P<0.01)。与此同时,大鼠肠缺血75分钟门静脉内毒素含量迅速上升,再灌注后2小时达峰值。结论急性肠缺血再灌注可致肠粘膜屏障破坏。使门、体循环 D-乳酸水平显著升高,其含量与小肠粘膜损害密切相关。因此,D-乳酸可作为新的血浆标志物应用于急性肠粘膜损害的早期诊断。

Relationship between plasma D(-)-lactate levels and acute intestinal injury in rats following ischemiareperfusion

Objective To determine the kinetics of plasma D(-)-lactate levels in both portal and systemic circulations ,and to examine whether elevated plasma D(-)-lactate would correlate to intestinal injury in rats subjected to acute intestinal ischemia-reperfusion.Methods Anesthetized rats underwent 75 minutes of superior mesenteric artery occlusion followed by 6 hours of reperfusion.Plasma D(-)-lac- rate levels were measured by an enzymatic spectrophotometric assay.Results It showed that intestinal ischemia for 75 minutes resulted in a significant elevation in D(-)-lactate levels in portal vein blood com- pared to baseline values(P<0.05).Plasma D(-)-lactate levels had a tendency to further increase after reperfusion up to 6 hours.Similar alterations in D(-)-lactate were also found in systemic circulation, there were no significant differences between the portal and systemic circulation at any time point.More- over,the histopathological evaluation scores were significantly correlated to the portal D(-)-lactate lev- els in animals at various time points(r=0.415,P<0.01).In addition,a remarkable rise of endotoxin concentration within portal vein was already found at the end of 75-minute ischemia(P<0.05),reach- ing a peak at 2 hours post-reperfusion.Conclusion These data suggest that acute intestinal ischemia is associated with fallure of mucosal barrier resulting in increased plasma D(-)-lactate levels in both portal and systemic blood.The subsequent reperfusion might cause further increase in D(-)-lactate levels, which correlated to the histopathological alterations.Plasma D(-)-lactate may be a useful marker of in- testinal injury following both ischemia and reperfusion insults.