Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, School of Medicine, University of Virginia, Charlottesville, Virginia.
Department of Medicine, Larner College of Medicine, University of Vermont, Burlington, Vermont.
Am J Perinatol. 2023 Jun;40(8):817-824. doi: 10.1055/s-0043-1761916. Epub 2023 Feb 16.
This study evaluated the effect of pregnancy on the pulmonary innate immune response in a mouse model of acute lung injury (ALI) using nebulized lipopolysaccharide (LPS).
Pregnant (day 14) C57BL/6NCRL mice and nonpregnant controls received nebulized LPS for 15 minutes. Twenty-four hours later, mice were euthanized for tissue harvest. Analysis included blood and bronchoalveolar lavage fluid (BALF) differential cell counts, whole-lung inflammatory cytokine transcription levels by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), and whole-lung vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), and BALF albumin by western blot. Mature bone marrow neutrophils from uninjured pregnant and nonpregnant mice were examined for chemotactic response using a Boyden chamber and for cytokine response to LPS by RT-qPCR.
In LPS-induced ALI, pregnant mice had higher BALF total cell ( < 0.001) and neutrophil counts ( < 0.001) as well as higher peripheral blood neutrophils ( < 0.01) than nonpregnant mice, but a similar increase (as compared with unexposed mice) in airspace albumin levels. Whole-lung expression of interleukin 6, tumor necrosis factor-α (TNF-α), and keratinocyte chemoattractant (CXCL1) was also similar. In vitro, marrow-derived neutrophils from pregnant and nonpregnant mice had similar chemotaxis to CXCL1 and -formylmethionine-leucyl-phenylalanine, but neutrophils from pregnant mice expressed lower levels of TNF ( < 0.001) and CXCL1 ( < 0.01) after LPS stimulation. In uninjured mice, VCAM-1 was higher in lungs from pregnant versus nonpregnant mice ( < 0.05).
In this model, pregnancy is associated with an augmented lung neutrophil response to ALI without increased capillary leak or whole-lung cytokine levels relative to the nonpregnant state. This may stem from increased peripheral blood neutrophil response and intrinsically increased expression of pulmonary vascular endothelial adhesion molecules. Differences in lung innate cell homeostasis may affect the response to inflammatory stimuli and explain severe lung disease in respiratory infection during pregnancy.
· Inhalation of LPS in midgestation versus virgin mice is associated with increased neutrophilia.. · This occurs without a comparative increase in cytokine expression.. · This may be explained by pregnancy-enhanced pre-exposure expression of VCAM-1 and ICAM-1..
本研究通过雾化脂多糖（LPS），在急性肺损伤（ALI）的小鼠模型中评估妊娠对肺部固有免疫反应的影响。
妊娠（第 14 天）C57BL/6NCRL 小鼠和非妊娠对照接受雾化 LPS 15 分钟。24 小时后，处死小鼠进行组织收获。分析包括血液和支气管肺泡灌洗液（BALF）的差异细胞计数、逆转录定量实时聚合酶链反应（RT-qPCR）测定全肺炎症细胞因子转录水平，以及 Western blot 测定全肺血管细胞间黏附分子 1（VCAM-1）、细胞间黏附分子 1（ICAM-1）和 BALF 白蛋白。使用 Boyden 室检测来自未受伤的妊娠和非妊娠小鼠的成熟骨髓中性粒细胞的趋化反应，并通过 RT-qPCR 检测 LPS 对其细胞因子反应。
在 LPS 诱导的 ALI 中，与非妊娠小鼠相比，妊娠小鼠的 BALF 总细胞（ < 0.001）和中性粒细胞计数（ < 0.001）以及外周血中性粒细胞（ < 0.01）更高，但肺泡空间白蛋白水平的增加与未暴露于 LPS 的小鼠相似。肺内白细胞介素 6、肿瘤坏死因子-α（TNF-α）和角质细胞趋化因子（CXCL1）的表达也相似。体外，来自妊娠和非妊娠小鼠的骨髓源性中性粒细胞对 CXCL1 和甲酰基甲硫氨酸亮氨酸苯丙氨酸的趋化性相似，但来自妊娠小鼠的中性粒细胞在 LPS 刺激后表达的 TNF（ < 0.001）和 CXCL1（ < 0.01）水平较低。在未受伤的小鼠中，与非妊娠小鼠相比，妊娠小鼠肺组织中的 VCAM-1 水平更高（ < 0.05）。
在该模型中，与非妊娠状态相比，妊娠与 ALI 时肺中性粒细胞反应增强而毛细血管渗漏或全肺细胞因子水平无增加有关。这可能源于外周血中性粒细胞反应增强和肺血管内皮黏附分子的固有表达增加。肺固有细胞内稳态的差异可能会影响对炎症刺激的反应，并解释妊娠期间呼吸道感染中严重的肺部疾病。
· 在妊娠中期和未孕小鼠中吸入 LPS 与中性粒细胞增多有关。· 这种情况的发生与细胞因子表达的增加无关。· 这可能是由于妊娠增强了 VCAM-1 和 ICAM-1 的预先暴露表达。
