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 ischemia reperfusion\

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( ) lactate 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 compared 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.Moreover,the histopathological evaluation scores were significantly correlated to the portal D( ) lactate levels 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),reaching a peak at 2 hours post reperfusion.Conclusion\ These data suggest that acute intestinal ischemia is associated with failure 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 intestinal injury following both ischemia and reperfusion insults.