Li Qi, Xiang Guoan, Peng Shouchun, Ji Wenjie
Department of Tuberculosis, Beijing Chest Hospital, Capital Medical University, Beijing, China.
Department of Respiratory, The Third Medical Center of Chinese People's Liberation Army General Hospital, Beijing, China.
Front Surg. 2022 Mar 2;9:837177. doi: 10.3389/fsurg.2022.837177. eCollection 2022.
Peripheral circulating monocytes and resident macrophages are heterogeneous effector cells that play a critical role in the maintenance and restoration of pulmonary integrity. However, their detailed dynamic changes in lipopolysaccharide (LPS)-induced acute lung injury (ALI) remain unclear. Here, we investigated the impact of mononuclear phagocyte cells in the development of LPS-induced ALI/Acute respiratory distress syndrome (ARDS) and described the relations between the dynamic phenotypic changes and pulmonary pathological evolution. In this study, mice were divided into two groups and intraperitoneally injected with normal saline (NS) or LPS, respectively. A series of flow cytometry assay was performed for the quantification of peripheral circulating monocyte subpopulations, detection of the polarization state of bronchoalveolar lavage fluid (BALF)-isolated alveolar macrophages (AMϕ) and pulmonary interstitial macrophages (IMϕ) separated from lung tissues. Circulating Ly6C monocytes expanded rapidly after the LPS challenge on day 1 and then decreased to day 7, while Ly6C monocytes gradually increased and returned to normal level on the 7th day. Furthermore, the expansion of M2-like AMϕ (CD64CD206) was peaked on day 1 and remained high on the third day, while the polarization state of IMϕ (CD64 CD11b) was not influenced by the LPS challenge at all the time points. Taken together, our findings show that Ly6C monocytes and M2-like AMϕ form the major peripheral circulation and pulmonary immune cell populations, respectively. The dynamic changes of mononuclear phagocyte in three compartments after the LPS challenge may provide novel protective strategies for mononuclear phagocytes.
外周循环单核细胞和驻留巨噬细胞是异质性效应细胞，在维持和恢复肺完整性方面发挥着关键作用。然而，它们在脂多糖（LPS）诱导的急性肺损伤（ALI）中的详细动态变化仍不清楚。在此，我们研究了单核吞噬细胞在LPS诱导的ALI/急性呼吸窘迫综合征（ARDS）发生发展中的作用，并描述了动态表型变化与肺病理演变之间的关系。在本研究中，将小鼠分为两组，分别腹腔注射生理盐水（NS）或LPS。进行了一系列流式细胞术检测，以定量外周循环单核细胞亚群，检测从支气管肺泡灌洗液（BALF）中分离的肺泡巨噬细胞（AMϕ）和从肺组织中分离的肺间质巨噬细胞（IMϕ）的极化状态。LPS攻击后第1天，循环中的Ly6C单核细胞迅速扩增，然后在第7天下降，而Ly6C单核细胞逐渐增加并在第7天恢复到正常水平。此外，M2样AMϕ（CD64CD206）的扩增在第1天达到峰值，并在第3天保持高水平，而IMϕ（CD64 CD11b）的极化状态在所有时间点均不受LPS攻击的影响。综上所述，我们的研究结果表明，Ly6C单核细胞和M2样AMϕ分别构成主要的外周循环和肺免疫细胞群体。LPS攻击后三个区室中单核吞噬细胞的动态变化可能为单核吞噬细胞提供新的保护策略。
