Kuhar Eva, Stewart Duncan J, Engelberts Doreen, Jahandideh Forough, Jeffers Matthew S, Khang Julie, Zhang Haibo, Kristof Arnold S, Thébaud Bernard, Vadivel Arul, Fergusson Dean A, Lalu Manoj M
Acute Care Researchl Program, Blueprint Translational Research Group, Ottawa Hospital Research Institute, Ottawa, ON, Canada.
Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.
Crit Care Explor. 2025 Jul 28;7(8):e1292. doi: 10.1097/CCE.0000000000001292. eCollection 2025 Aug 1.
Direct preclinical lipopolysaccharide acute lung injury (ALI) models are commonly used to study acute respiratory distress syndrome. Differences in lipopolysaccharide delivery methods may impact lung injury severity and reproducibility.
We hypothesized that the severity and variability of ALI outcomes in mice would differ depending on the technique of lipopolysaccharide administration.
Male and female C57BL/6 mice were administered lipopolysaccharide (2.25 mg/kg) via four methods: 1) intratracheal intubation; 2) intranasal; 3) surgical transtracheal by either needle puncture; or 4) by catheter. ALI severity and variability were assessed at 72 hours post-lipopolysaccharide via histological scoring and bronchoalveolar lavage fluid (BALF) analysis (total protein, cell counts, interleukin-6 [IL-6]). The relative distribution of Evans Blue dye was also assessed for each model (lungs vs. stomach).
Distinct lung injury patterns were observed between the four methods. The transtracheal with catheter method demonstrated significantly greater lung injury scores than the intratracheal intubation and intranasal techniques. Both transtracheal methods produced greater alveolar neutrophil counts, increased proteinaceous debris, fewer hyaline membranes, and lower variability than non-surgical techniques. The transtracheal with catheter method produced higher BALF total cell counts and IL-6 levels than intratracheal intubation. Transtracheal methods also resulted in more localized Evans Blue dye distribution in the lungs. Male mice exhibited more severe lung injury scores and higher BALF protein concentrations than females.
This study demonstrates that the choice of technique to administer lipopolysaccharide impacts injury severity, phenotype, and variability. The surgical transtracheal with catheter technique produced the most robust and least variable ALI phenotype; however, this technique is associated with increased procedural complexity. Our results will allow researchers to tailor their model choice to align with their specific study objectives.
直接的临床前脂多糖急性肺损伤（ALI）模型常用于研究急性呼吸窘迫综合征。脂多糖给药方法的差异可能会影响肺损伤的严重程度和可重复性。
我们假设小鼠ALI结果的严重程度和变异性会因脂多糖给药技术的不同而有所差异。
通过四种方法给雄性和雌性C57BL/6小鼠注射脂多糖（2.25毫克/千克）：1）气管插管；2）鼻内给药；3）通过针刺进行外科经气管给药；或4）通过导管给药。在脂多糖注射后72小时，通过组织学评分和支气管肺泡灌洗（BALF）分析（总蛋白、细胞计数、白细胞介素-6 [IL-6]）评估ALI的严重程度和变异性。还评估了每个模型中伊文思蓝染料的相对分布（肺与胃）。
四种方法之间观察到明显不同的肺损伤模式。经导管经气管给药方法的肺损伤评分明显高于气管插管和鼻内给药技术。两种经气管给药方法产生的肺泡中性粒细胞计数更高、蛋白质碎片增加、透明膜减少，并且与非手术技术相比变异性更低。经导管经气管给药方法的BALF总细胞计数和IL-6水平高于气管插管。经气管给药方法还导致伊文思蓝染料在肺中的分布更局限。雄性小鼠的肺损伤评分比雌性更严重，BALF蛋白浓度更高。
本研究表明，脂多糖给药技术的选择会影响损伤的严重程度、表型和变异性。经导管外科经气管给药技术产生了最强烈且变异性最小的ALI表型；然而，该技术与操作复杂性增加相关。我们的结果将使研究人员能够根据其特定的研究目标调整模型选择。
