体外膜肺氧合对心死亡猪供肝的修复作用及其机制研究

Repair mechanism of extracorporeal membrane oxygenation on liver after cardiac death

目的研究体外膜肺氧合（ECMO）对心死亡猪供肝的修复作用及其机制。方法采用随机数字表法将巴马小型猪12头分为ECMO修复组（实验组）和冷保存组（对照组），每组6头。两组猪均以静脉推注氯化钾的方法诱导心脏停搏，给予标准心肺复苏30min后宣布心死亡，建立猪心死亡模型。实验组应用ECMO行自体血循环4h；对照组获取肝脏并置于4℃的UW液中冷保存4h。取两组肝组织，检测ATP、丙二醛、超氧化物歧化酶（SOD）、谷胱甘肽、热休克蛋白70（HSP70）和细胞间黏附分子-1（ICAM-1）含量，并行肝组织切片电镜检测。结果心死亡时（经历30min热缺血后），两组肝组织ATP含量下降到不足基础值的40％，经ECMO修复4h时逐渐恢复到基础水平，而对照组ATP含量逐渐下降。与冷保存4h时对照组相比，ECMO修复4h时实验组SOD、谷胱甘肽和HSP70含量均明显增加（P〈0．05），丙二醛和ICAM-1明显减少（P〈0．05）。透射电镜下可见，心死亡时两组猪肝组织超微结构的改变一致，胞浆内出现空泡，细胞核明显变形，染色质边集，线粒体肿胀，部分线粒体嵴消失；ECMO修复4h时染色质边集减轻，线粒体轻度肿胀，可见线粒体嵴。结论猪心死亡后，应用ECMO可恢复供肝的氧气和营养物质供应，避免供肝的冷保存损伤并增加能量储备。通过上调谷胱甘肽、SOD和HSP-70等保护性蛋白减轻肝脏的氧化应激损伤，同时保护肝窦内皮细胞，改善微循环，减轻中性粒细胞浸润。

Objective To study the repair mechanism of extracorporeal membrane oxygenation on liver after cardiac death. Methods Twelve pigs were equally randomized to ECMO group and control group. Cardiac arrest was induced by administration of 1 g KCL intravenously, followed by 30 min cardiopulmonary resuscitation according to the standard guideline. Cannulas were placed through inferior vena cava and abdominal aorta, then connected to ECMO extracorporeal circulation pipes in ECMO group for 4 h. The livers were stored in cold UW for 4 h in control group. ATP, superoxide dismutase （SOD）, glutathionein （GSH）, malondialdehyde （MDA）, heat shock protein 70 （HSPT0） and intercellular cell adhesion rnolecule-1 （ICAM-1） were detected in liver tissue. Pathological change was observed by optical microscope and electron microscopy. Results Tissue ATP decreased to less than 40% of baseline after 30 vain of warm ischemia, then restored to 70% after 2 h of ECMO and returned to baseline after 4 h, while ATP of control group continued a further decline. As compared with control group, SOD, GSH and HSP70 increased significantly in ECMO group （P〈0. 05） , while MDA and ICAM-I decreased significantly （P〈0. 05）. Pathological changes of liver tissue observed by optical microscope and electron microscopy in ECMO group were significantly were significantly alleviated as compared with those in control group. Conclusion ECMO can supply oxygen and nutrients to liver after warm ischemia and increase energy reserve. By upregulating GSH, SOD and HSP-70 and other protective proteins, ECMO alleviates oxidative stress and liver damage. ECMO also improves microcirculation and reduces neutrophil infiltration by protecting sinusoidal endothelial cells.