Comparative Evaluation of Lipopolysaccharide Administration Methods to Induce Acute Lung Injury in Murine Models: Efficacy, Consistency, and Technical Considerations
Bibliographic record
Abstract
CONTEXT: 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. HYPOTHESIS: We hypothesized that the severity and variability of ALI outcomes in mice would differ depending on the technique of lipopolysaccharide administration. METHODS AND MODELS: 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). RESULTS: 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. INTERPRETATION AND CONCLUSIONS: 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.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.009 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".