Ferreira Jorge M C, Huhle Robert, Müller Sabine, Schnabel Christian, Mehner Mirko, Koch Thea, Gama de Abreu Marcelo
Department of Anesthesiology and Intensive Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus Dresden at Technische Universität Dresden, Dresden, Germany.
Department of Anesthesiology and Intensive Care Medicine, Clinical Sensoring and Monitoring Group, University Hospital Carl Gustav Carus Dresden at Technische Universität Dresden, Dresden, Germany.
Front Physiol. 2022 Apr 11;13:838834. doi: 10.3389/fphys.2022.838834. eCollection 2022.
: Mechanical ventilation (MV) inflicts stress on the lungs, initiating or increasing lung inflammation, so-called ventilator-induced lung injury (VILI). Besides overdistention, cyclic opening-and-closing of alveoli (atelectrauma) is recognized as a potential mechanism of VILI. The dynamic stretch may be reduced by positive end-expiratory pressure (PEEP), which in turn increases the static stretch. We investigated whether static stretch modulates the inflammatory response of rat type 2 alveolar epithelial cells (AECs) at different levels of dynamic stretch and hypothesized that static stretch increases pro-inflammatory response of AECs at given dynamic stretch. AECs, stimulated and not stimulated with lipopolysaccharide (LPS), were subjected to combinations of static (10, 20, and 30%) and dynamic stretch (15, 20, and 30%), for 1 and 4 h. Non-stretched AECs served as control. The gene expression and secreted protein levels of interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein 2 (MIP-2) were studied by real-time polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively. The effects of static and dynamic stretch were assessed by two-factorial ANOVA with planned effects post-hoc comparison according to Šidák. Statistical significance was considered for < 0.05. In LPS-stimulated, but not in non-stimulated rat type 2 AECs, compared to non-stretched cells: 1) dynamic stretch increased the expression of amphiregulin (AREG) ( < 0.05), MCP-1 ( < 0.001), and MIP-2 (<0.05), respectively, as well as the protein secretion of IL-6 ( < 0.001) and MCP-1 ( < 0.05); 2) static stretch increased the gene expression of MCP-1 ( < 0.001) and MIP-2, but not AREG, and resulted in higher secretion of IL-6 ( < 0.001), but not MCP-1, while MIP-2 was not detectable in the medium. In rat type 2 AECs stimulated with LPS, static stretch increased the pro-inflammatory response to dynamic stretch, suggesting a potential pro-inflammatory effect of PEEP during mechanical ventilation at the cellular level.
机械通气（MV）会对肺部造成应激，引发或加剧肺部炎症，即所谓的呼吸机诱导的肺损伤（VILI）。除了过度扩张外，肺泡的周期性开闭（肺不张伤）被认为是VILI的一种潜在机制。呼气末正压（PEEP）可降低动态牵张，进而增加静态牵张。我们研究了在不同水平的动态牵张下，静态牵张是否会调节大鼠II型肺泡上皮细胞（AECs）的炎症反应，并假设在给定的动态牵张下，静态牵张会增加AECs的促炎反应。用脂多糖（LPS）刺激和未刺激的AECs分别接受静态（10%、20%和30%）和动态牵张（15%、20%和30%）的组合处理1小时和4小时。未牵张的AECs作为对照。分别通过实时聚合酶链反应（RT-qPCR）和酶联免疫吸附测定（ELISA）研究白细胞介素-6（IL-6）、单核细胞趋化蛋白-1（MCP-1）和巨噬细胞炎性蛋白2（MIP-2）的基因表达和分泌蛋白水平。通过双因素方差分析评估静态和动态牵张的影响，并根据Šidák法进行事后比较的计划效应分析。P<0.05被认为具有统计学意义。在LPS刺激的大鼠II型AECs中，而非未刺激的细胞中，与未牵张的细胞相比：1）动态牵张分别增加了双调蛋白（AREG）（P<0.05）、MCP-1（P<0.001）和MIP-2（P<0.05）的表达，以及IL-6（P<0.001）和MCP-1（P<0.05）的蛋白分泌；2）静态牵张增加了MCP-1（P<0.001）和MIP-2的基因表达，但未增加AREG的表达，并导致IL-6的分泌增加（P<0.001），但未增加MCP-1的分泌，而培养基中未检测到MIP-2。在LPS刺激的大鼠II型AECs中，静态牵张增加了对动态牵张的促炎反应，提示在机械通气过程中，PEEP在细胞水平上可能具有促炎作用。
