Acute lung injury (ALI) and/or acute respiratory distress syndrome (ARDS) are critical life-threatening syndromes characterized by the infiltration of a large number of granulocytes (mainly neutrophils) that lead to an excessive inflammatory response. Emodin (Emo) is a naturally occurring anthraquinone derivative and an active ingredient of Chinese medicine. It is believed to have anti-inflammatory effects. In this study, we examined the impact of Emo on the pulmonary inflammatory response and the granulocytes function in a rat model of lipopolysaccharide (LPS)-induced ALI. Treatment with Emo protected rat against LPS-induced ALI. Compared to untreated rat, Emo-treated rat exhibited significantly ameliorated lung pathological changes and decreased tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). However, Emo has no protective effect on the rat model of acute lung injury with granulocyte deficiency. In addition, treatment with Emo enhanced the bactericidal capacity of LPS-induced granulocytes via the up-regulation of the ability of granulocytes to phagocytize bacteria and generate neutrophil extracellular traps (NETs). Emo also downregulated the respiratory burst and the expression of reactive oxygen species (ROS) in LPS-stimulated granulocytes, alleviating the damage of granulocytes to surrounding tissues. Finally, Emo can accelerate the resolution of inflammation by promoting apoptosis of granulocytes. Our results provide the evidence that Emo could ameliorates LPS-induced ALI via its anti-inflammatory action by modulating the function of granulocytes. Emo may be a promising preventive and therapeutic agent in the treatment of ALI.

中文翻译：

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大黄素通过影响粒细胞功能减轻LPS诱导的肺损伤大鼠炎症反应。

急性肺损伤 (ALI) 和/或急性呼吸窘迫综合征 (ARDS) 是危及生命的严重综合征，其特征是大量粒细胞（主要是中性粒细胞）浸润，导致过度炎症反应。大黄素（Emo）是一种天然存在的蒽醌衍生物，是中药的有效成分。它被认为具有抗炎作用。在这项研究中，我们在脂多糖 (LPS) 诱导的 ALI 大鼠模型中检查了 Emo 对肺部炎症反应和粒细胞功能的影响。用 Emo 治疗可保护大鼠免受 LPS 诱导的 ALI。与未治疗的大鼠相比，Emo 治疗的大鼠表现出显着改善的肺病理变化和降低的肿瘤坏死因子-α (TNF-α) 和白细胞介素-1β (IL-1β)。然而，Emo对粒细胞缺乏急性肺损伤大鼠模型无保护作用。此外，Emo 治疗通过上调粒细胞吞噬细菌和产生中性粒细胞胞外陷阱 (NETs) 的能力来增强 LPS 诱导的粒细胞的杀菌能力。Emo 还下调 LPS 刺激的粒细胞中的呼吸爆发和活性氧 (ROS) 的表达，减轻粒细胞对周围组织的损伤。最后，Emo可以通过促进粒细胞凋亡来加速炎症的消退。我们的结果提供了证据，即 Emo 可以通过调节粒细胞的功能通过其抗炎作用来改善 LPS 诱导的 ALI。Emo 可能是治疗 ALI 的一种有前途的预防和治疗药物。