Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
Anesth Analg. 2013 Feb;116(2):327-35. doi: 10.1213/ANE.0b013e31827aec06. Epub 2013 Jan 9.
Although anesthetic-induced inhibition of lipopolysaccharide (LPS)-induced lung injury has been recognized, the underlying mechanism is obscure. Some studies suggest that reactive oxygen species (ROS) by isoflurane play a crucial role for anesthetic-induced protective effects on the brain or the heart; however, it still remains controversial. In this study, we examined the role of isoflurane-derived ROS in isoflurane-induced inhibition of lung injury and nuclear factor κB (NFκB) activation in LPS-challenged rat lungs.
Male Sprague-Dawley rats were subjected to inhalation of 1.0 minimum alveolar concentration of isoflurane for 60 minutes, and intratracheal LPS 0.1 mg was administered 60 minutes later. In some cases, ROS scavenger, 2-mercaptopropinyl glycine or N-acetylcysteine was given 30 minutes before isoflurane. ROS generation was measured by fluorometer before LPS challenge and 4 hours after. Isoflurane's preconditioning effect was assessed by histologic examination, protein content, neutrophil recruitment, and determination of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 levels in bronchoalveolar lavage fluid and lung tissue. Western blotting measured phosphorylation of inhibitory κB α (ser 32/36), NFκB p65, and inducible nitric oxide synthase (iNOS). TNF-α and IL-6 mRNA expression and immunofluorescence staining for iNOS were also assessed.
Isoflurane preconditioning reduced inflammatory lung injury and TNF-α, IL-1β, and IL-6 release in the lung. Isoflurane upregulated ROS generation before LPS but inhibited a ROS burst after LPS challenge. ROS scavenger administration before isoflurane abolished the isoflurane preconditioning effect as well as isoflurane-induced inhibition of phosphorylation of inhibitory κBα, NFκB p65, iNOS activation, and mRNA expression of TNF-α and IL-6 in acute LPS-challenged lungs.
This study suggests a crucial role of upregulated ROS generation by isoflurane for modification of inflammatory pathways by isoflurane preconditioning in acute inflammation of the lung.
尽管人们已经认识到麻醉诱导物对脂多糖（LPS）诱导的肺损伤的抑制作用，但其中的机制尚不清楚。一些研究表明，异氟醚产生的活性氧（ROS）对于麻醉诱导物对大脑或心脏的保护作用至关重要；然而，这仍然存在争议。在这项研究中，我们研究了异氟醚衍生的 ROS 在异氟醚抑制 LPS 刺激的大鼠肺损伤和核因子 κB（NFκB）激活中的作用。
雄性 Sprague-Dawley 大鼠吸入 1.0 最低肺泡浓度的异氟醚 60 分钟，然后在 60 分钟后经气管内给予 LPS0.1mg。在某些情况下，ROS 清除剂 2-巯基丙酰甘氨酸或 N-乙酰半胱氨酸在异氟醚之前 30 分钟给予。在 LPS 攻击前和 4 小时后通过荧光计测量 ROS 的产生。通过组织学检查、蛋白质含量、中性粒细胞募集以及测定支气管肺泡灌洗液和肺组织中的肿瘤坏死因子（TNF）-α、白细胞介素（IL）-1β和 IL-6 水平来评估异氟醚的预处理作用。Western 印迹测量抑制性 κBα（丝氨酸 32/36）、NFκB p65 和诱导型一氧化氮合酶（iNOS）的磷酸化。还评估了 TNF-α 和 IL-6 mRNA 表达和 iNOS 的免疫荧光染色。
异氟醚预处理减轻了肺部的炎症性肺损伤和 TNF-α、IL-1β 和 IL-6 的释放。异氟醚在 LPS 前增加了 ROS 的产生，但抑制了 LPS 后 ROS 的爆发。异氟醚前给予 ROS 清除剂消除了异氟醚预处理的作用以及异氟醚诱导的磷酸化抑制性 κBα、NFκB p65、iNOS 激活以及急性 LPS 刺激的肺中 TNF-α 和 IL-6 的 mRNA 表达的抑制。
本研究表明，异氟醚产生的 ROS 上调对于异氟醚预处理修饰急性肺炎症中的炎症途径具有重要作用。
