摘要
前言
急性肺损伤(Acute lung injury，ALI)是一种包括不同程度的肺上皮和肺血管内皮细胞损伤而导致肺泡通透性增加的病理过程，其病理特征主要是肺内多形核白细胞(Poly morphonuclear neutrophil，PMN)浸润，PMN通过“呼吸爆发”产生活性氧簇杀伤细菌，同时产生的活性氧自由基、酶类、NO及细胞因子介导组织损伤。激活的PMN同内皮细胞粘附进一步加重组织损伤，ICAM-1作为重要炎性介质在肺部的炎性反应中起重要作用，且ICAM-1表达的水平与肺损伤程度密切相关，TNF-α能诱导肺内皮细胞活化、白细胞迁移、粒细胞脱颗粒和毛细血管渗漏，最终导致肺内弥漫性毛细血管内皮损伤引起肺泡毛细血管通透性增加，TNF-α还诱导内皮细胞和巨噬细胞释放IL-1，IL-1随后又刺激其它细胞因子的合成，在急性肺损伤时还伴随表面活性物质的改变。麻醉药和麻醉方式可影响肺部的炎性反应，但七氟醚和地氟醚对损伤状态下肺部的影响研究较少。
本实验以内毒素复制大鼠急性肺损伤模型，研究七氟醚和地氟醚对内毒素致急性肺损伤鼠肺的影响和机制。分四部分，包括：一、七氟醚和地氟醚对急性肺损伤肺泡及毛细血管膜通透性的影响；二、七氟醚和地氟醚对急性肺损伤肺部氧自由基和NO代谢的影响；三、七氟醚和地氟醚对ICAM-1和TNF-α的影响；四、七氟醚和地氟醚对正常肺和急性肺损伤后肺泡灌洗液(Pulmonary alveolar lavage fluid，PALF)内表面活性物质SP-A和磷脂酰胆碱(phosphatidylcholine，PC)含量的影响。
实验材料
1．实验动物：Wistar大鼠116只，雌雄不限，由中国医科大学实验动物
病原体和增加清除细菌的能力。前几部分实验结果证明七氟醚减轻内毒素
致肺损伤肺部炎性反应，同时抑制机体对细菌的杀伤能力，SP－A合成下降
的意义与上述结果一致。地氟醚对PALF内SP－A和PC及七氟醚和地氟
醚对急性肺损伤时PALF内SP－A和PC的影响机制不清，还有待于进一步
研究。
结 论
1．1．0和＊ 5 MAC七氟醚降低内毒素致急性肺损伤肺泡毛细血管膜的
通透性；二．OMAC地氟醚影响较小；1．SMAC地氟醚增加肺泡毛细血管膜的
通透性。
2．1．0和＊ 5 MAC七氟醚抑制内毒素致急性肺损伤的氧化应激反应，
降低NO代谢；1．OMAC地氟醚的影响较小，1．SMAC地氟醚加重了肺部的
氧化应激反应。
3．l．0和 1．5 MAC七氟醚抑制内毒素致急性肺损伤肺组织 TNF－
amRNA、ICAM－lmRNA和 iNOSmRNA及相应蛋白的表达，减轻了肺部的
炎性反应；1．OMAC地氟醚影向较小，1．SMAC地氟醚增加 TNF－amRNA＼
ICAM．lmRNA和 iNOSmRNA及相应蛋白的表达，加重了肺部的炎性反应。
4．l．0和 1．5 MAC七氟醚和地氟醚抑制正常肺哪一A和饥的合成，
剂量依赖关系不明显，轻度降低内毒素致急性肺损伤后PALF内SP－A和
PC含量，剂量依赖关系不明显。
Acute lung injury is a pathological process during which different degrees of injury of alveolar epithelial cells and lung vascular endothelial cells result in in-crease of alveolar permeability, characterized by infiltration of polymorphonucle-ar neutrophil (PMN) in the lung, bactericidal activity of free oxygen radicals produced via " respiratory burst" , tissue injury mediated by the production of free oxygen radicals, enzymes and cytokines. Tissue injury is more aggravated by activated PMN and adhesion of endothelial cells. ICAM - 1 plays a crucial role in the inflammatory response as an important inflammatory mediator, whose level of expression is closely related to the degree of lung injury. Activation of lung endothelial cells, migration of leukocytes, degranulation of granulocytes and capillary leakage induced by TNF - a results in diffuse lung microvascular endothelial cells injury and increase in microvascular permeability. TNF -α can also induce the release of IL - 1 from endothelial cells and mac
rophage, which stimulate the synthesis of other cytokine in turn. Accompanied surfactant chan-ges also occur in the acute lung injury. Inflammatory response can be influenced by anesthetics and method of anesthesia, but there are rare studies on the influ-ence of sevoflurane and desflurane on the injured lung.
In this experiment, the influence and mechanism of sevoflurane and desflu-rane on acute lung injury in rats were studied in the model of LPS - induced a-cute lung injury in rats. The experiment was divided in 4 parts, part 1: influ-ence of sevoflurane and desflurane on the permeability of alveoli and capillary in
acute lung injury; part 2; influence of sevoflurane and desflurane on metabolism of oxygen free radicals and NO in acute lung injury; part 3 : influence of sevoflu-rane and desflurane on ICAM - 1 and TNF -α; part 4: influence of sevoflurane and desflurane on the contents of SP ?A and phosphatidylcholine ( PC) in pul-monary alveolar lavage fluid (PALF) of normal and acute injured lungs.
- Materials
Experimental animals: 116 Wistar rats, regardless of sex, provided by Chi-na Medical University Laboratory Animal Center, weight 200 ~ 290g.
Experimental instruments: Ohmeda 7000 Aneshesia machine, animal venti-lator (Havard 55 -3438) , Datex anesthetic gas monitor, Olympus light micro-scope, RM -6000 multi -lead physiology monitor (Kohden, Japan) , PTC -100 PCR amplification device,KODAKID gel imaging analytical system, Dupont ST -21 low temperature and high speed centrifuger( U. S. A) , Olympus AX70 microphotograph system (Japan) , MetaMorph/Olympus DP10/BX51 microimage analytical system( Japan) , Metamorph image system( UIC Company, U. S. A) , KADAKID gel image analyzing system (USA) , GIS -700D digitized gel scan-ning analyzing system (Shanghai). Hitachi transmission electron microscope.
Chemical and reagents: pentobarbital sodium (ShangHai) , Lipopolysac-charide(Escheruchia coli 055: B5, Sigma ) , TNF - α ICAM - 1 immunohisto-chemicology were supplied by WuHan BoShiDe company and iNOS immunohis-tochenicology supplied by Beijing Zhongshan company. SP - A antibody was sup-plied by Santa Cruze company.
Methods
1. Influence of sevoflurane and desflurane on the permeability of alveoli and capillary in acute lung injury of rats caused by LPS. After anesthesia, 36 Wistar rats were randomly assigned to one of 6 groups after injection Evans blue50mg/kg. Group C: mechanically ventilated for 4 hours after injection of 1.
2 ml normal saline; Group L: mechanically ventilated for 4 hours after injection of LPS 5 mg/kg; Group S1L and S2L: mechanically ventilated for 4 hours after in-jection of LPS 5 mg/kg, inhaled 1.0 MAC and 1. 5 MAC of sevoflurane at the same time; Group D1L and D2L: mechanically ventilated for 4 hours after injec-tion of LPS 5 mg/kg, inhaled 1.0 MAC and 1.5 MAC of desflurane at the same time. Lung permeability index ( LPI) , Evans blue leakeage, lung wet/dry weight ratio ( W/D) and lung water content, and inflammatory cells percentage in pulmonary
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