Xue Yao, Zhang Yunqian, Chen Li, Wang Yan, Lv Zhou, Yang Li-Qiao, Li Siyuan
Department of Anesthesiology, The Affiliated Shenmu Hospital of Northwest University, Shenmu, Shaanxi 719300, P.R. China.
Department of Anesthesiology and Surgical Intensive Care Unit, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, P.R. China.
Exp Ther Med. 2022 Aug 22;24(4):632. doi: 10.3892/etm.2022.11569. eCollection 2022 Oct.
Acute lung injury (ALI) is a common complication in patients with sepsis and is accompanied by high mortality. The present study aimed to investigate if the organic compound citrulline has a protective against lipopolysaccharide (LPS)-stimulated ALI and its potential mechanisms. ALI was induced in mice by intraperitoneal (i.p.) injection of LPS (10 mg/kg). Citrulline (1 g/kg/day) was administrated i.p. 7 days prior to LPS injection. Mouse lung vascular endothelial cells (MLVECs) were divided into five groups: Control, LPS, LPS + Cit, LPS + N-acetyl-L-cysteine (NAC) and LPS + Cit + ML385. Lung injury was determined by morphology changes. Apoptosis and pyroptosis were detected using western blot analysis and immunofluorescence. The present results indicated that citrulline can significantly attenuate ALI. Citrulline pretreatment decreased the expression of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome and decreased pyroptosis and apoptosis. Intervention with the total reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine attenuated NLRP3 inflammasome-associated pyroptosis and apoptosis in LPS-treated MLVECs. Citrulline pretreatment inhibited pyroptotic cell death and apoptosis induced by LPS. Citrulline decreased accumulation of intracellular ROS and activated the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. Furthermore, the Nrf2 inhibitor ML385 reversed ROS generation, NLRP3 inflammasome-mediated pyroptosis and apoptosis suppressed by citrulline. In summary, the present data demonstrated that citrulline may confer protection against ALI via inhibition of ROS/NLRP3 inflammasome-dependent pyroptosis and apoptosis via the Nrf2 signaling pathway.
急性肺损伤（ALI）是脓毒症患者常见的并发症，死亡率很高。本研究旨在探究有机化合物瓜氨酸是否对脂多糖（LPS）诱导的ALI具有保护作用及其潜在机制。通过腹腔注射LPS（10 mg/kg）诱导小鼠发生ALI。在注射LPS前7天腹腔注射瓜氨酸（1 g/kg/天）。将小鼠肺血管内皮细胞（MLVECs）分为五组：对照组、LPS组、LPS+瓜氨酸组、LPS+N-乙酰半胱氨酸（NAC）组和LPS+瓜氨酸+ML385组。通过形态学变化确定肺损伤情况。采用蛋白质印迹分析和免疫荧光检测细胞凋亡和焦亡。目前的结果表明，瓜氨酸可显著减轻ALI。瓜氨酸预处理降低了含核苷酸结合寡聚化结构域样受体蛋白3（NLRP3）炎性小体的表达，并减少了焦亡和凋亡。用总活性氧（ROS）清除剂N-乙酰半胱氨酸干预可减轻LPS处理的MLVECs中NLRP3炎性小体相关的焦亡和凋亡。瓜氨酸预处理可抑制LPS诱导的焦亡细胞死亡和凋亡。瓜氨酸减少了细胞内ROS的积累并激活了核因子红细胞2相关因子2（Nrf2）信号通路。此外，Nrf2抑制剂ML385逆转了瓜氨酸抑制的ROS生成、NLRP3炎性小体介导的焦亡和凋亡。总之，目前的数据表明，瓜氨酸可能通过Nrf2信号通路抑制ROS/NLRP3炎性小体依赖性焦亡和凋亡，从而对ALI起到保护作用。
