不同剂量异丙酚对大鼠小肠缺血再灌注后肺损伤超微结构的影响

Effects of different doses of propofol on the pulmonary infrastructure after intestinal ischemia-reperfusion in rats

目的 探讨不同临床剂量异丙酚对大鼠小肠缺血再灌注后肺损伤肺组织钙离子含量变化和肺组织超微结构改变的影响及其保护作用。方法 雄性SD大鼠40只,随机分为假手术对照组(Ⅰ组)。小肠缺血再灌注组(Ⅱ组)及分别给予异丙酚4mg·kg-1·h-1、8mg·kg-1·h-1、10mg·kg-1·h-1(Ⅳ、Ⅳ、Ⅴ)5组;制作小肠缺血再灌注模型。实验结束即刻取部分肺组织固定于2.5％戊二醛行透射电镜检查肺组织超微结构,部分肺组织用原子吸收分光光度法测钙离子含量。结果IIR后Ⅱ组、Ⅲ组肺组织钙离子含量明显升高,与Ⅰ组、Ⅳ组、Ⅴ组相比均有非常显著差异(P<0.01),Ⅳ组、Ⅴ组与Ⅰ组相比无统计学差异,同时Ⅱ组、Ⅲ组肺组织钙离子含量相比显著差异(P<0.05)。Ⅱ组肺组织超微结构明显受损,异丙酚用药组肺组织超微结构均明显改善,尤其Ⅳ组、Ⅴ组两组除线粒体结构轻微改变外基本接近正常。结论 钙离子在大鼠小肠缺血再灌注后肺损伤中有重要作用,临床剂量异丙酚可明显降低肺组织钙离子含量,并对肺组织超微结构产生保护作用。

Objective To study the effects of different doses of propofol on the changes in lung Ca content and pulmonary ultrastructure caused by intestinal ischemia-reperfusion (IIR) induced lung injury. Methods Forty male SD rats weighing 200-250g were randomly divided into 5 groups of 8 rats each: group I sham operation (control group): group II small intestinal ischemia-reperfusion; group III propofol 4 mg-kg-1-h-1; group IV propofol 8mg-kg-h-1; group V propofol 10 mg-kg-1-h-1. The rats were anesthetized with 3% pentobarbital 40mg-kg-1 ip. Right carotid artery and left internal jugular vein were cannulated for BP and pulmonary arteral pressure (PAP) monitoring and fluid and drug administration. The animals were tracheotomized and mechanically ventilated. PETCO2 was maintained at 4 .67- 5.60 kPa. Abdomen was opened. Superior mesenteric artery (SMA) was isolated and clamped for 60 min followed by 120min reperfusion. In group III , IV and V 10min before SMA occlusion was released different doses of propofol was continuously infused until the end of experiment. In group I and II isovolemic normal saline was infused instead of propofol. Lung Ca2+ content was measured and ultrastructure of the lung examined. Results The lung tissue Ca2+ content increased significantly after IIR in group II and III as compared with group I , IV and V ( P<0.01) .There was also significant difference in the lung tissue Ca2+ content between group II and III . The pulmonary ultrastructure was badly injured in group II but in the three propofol groups ( III , IV , V ) the ultrastructural injury of the lung was greatly ameliorated.Conclusion Ca2+ plays an important role in the lung injury induced by intestinal ischemia reperfusion and the clinical doses of propofol can reduce lung tissue Ca2+ content and have protective effect on the pulmonary ultrastructure.