延时低温对急性肺损伤早期炎症反应和肺水的影响

Effects of delayed hypothermia on earlier inflammatory reaction and lung water of acute lung injury induced by intestinal ischemia-reperfusion in rabbits

目的研究延迟开始的低温对肠缺血再灌注所致急性肺损伤早期炎症反应和肺水的影响。方法新西兰大白兔60只(10只/组),随机分为空白对照组(肛温37～38℃,假手术组)、缺血对照组(肛温37～38℃)、浅低温组(肛温32～35℃)、中低温组(肛温28～31.9℃)、延迟浅低温组(直肠目标温度32～35℃)、延迟中低温组(直肠目标温度28～31.9℃)。实验组采用完全夹闭肠系膜上动脉(super mesenteric artery,SMA)1h,开放后再灌注的方法制备肠缺血再灌注(Intestine Ischemia Reperfusion,IIR)致急性肺损伤(acute lung injury,ALI)模型。采用体表降温的方法控制实验动物体温。再灌注6h后测定支气管肺泡灌洗液(Bronchoalveolar Lavage Fluid,BALF)TNF-α、IL-1β、IL-6、IL-10水平;再灌注6h后处死动物取肺组织标本,测定肺组织湿/干比值。结果和空白对照组比较,实验组BALF中TNF、IL-1、IL-6、IL-10水平升高,肺组织肺水增加。在实施低温治疗后,同缺血对照组相比,上述肺损伤的表现得到了改善,延迟开始的低温治疗也有一定的效果。结论浅低温和中低温可以有效改善IIR导致ALI动物模型的早期炎症反应,减轻肺组织损伤的程度;延迟开始的低温也有一定的效果。

Objective To study the effects of delayed hypothermia on earlier inflammatory reaction and lung water of acute lung injury induced by intestinal ischemia-reperfusion in rabbits. Methods 60 healthy rabbits were randomly divided into 6 groups （n=10 per group）： normothermia intestinal ischemia-reperfusion groups （rectal temperature 37-38℃）; mild hypothermia group （rectal temperature 32-35℃）; moderate hypothermia group （rectal temperature 28-31.9℃）; delayed mild hypothermia group （rectal temperature 32-35℃）; delayed moderate hypothermia （rectal temperature 28-31.9℃）; normothermia control group （rectal temperature 37-38℃, the sham group）.The rabbit models of acute lung injury were produced by clamping super mesenteric artery （SMA） for 1 hour and declamping SMA for 6 hours. Hypothermia was induced by surface cooling. Six hours after intestinal ischemia-reperfusion,bronchoalveolar lavage fluid （BALF） were collected to test levels of TNF-α,IL-1β,IL-6,IL-10. All rabbits were killed to measure lung water in tissues of lung. Results In IR groups, levels of TNF-α,IL-1β,IL-6,IL-10 in BALF and lung water increased. The acute lung injury induced by intestinal ischemia-reperfusion were improved by hypothermia. Mild hypothermia was similar with moderate hypothermia in treatment of ALI induced by IIR. Delayed hypothermia improved partialy the acute lung injury induced by intestinal ischemia -reperfusion. Conclusion Mild hypothermia and moderate hypothermia can improved significantly ALI induced by IIR in rabbits. Delayed hypothermia improved partialy the acute lung injury by intestinal ischemia-reperfusion.