Journal Article

Establishment of rat model for aspiration pneumonia and potential mechanisms

Chen, Junfeng, Tang, Yuedong, Shen, Jie, Hu, Hanbing, Memet, Obulkasim, Dun, Yu, Bao, Xuanrong, Shao, Yiru

2025

Overview

Background Aspiration pneumonia is a severe health concern, particularly for ICU patients with impaired airway defenses. Current animal models fail to fully replicate the condition, focusing solely on chemical lung injury from gastric acid while neglecting pathogen‐induced inflammation. This gap hinders research on pathogenesis and treatment, creating an urgent need for a clinically relevant model. This study aimed to develop an improved rat model of aspiration pneumonia by combining hydrochloric acid (HCl) and lipopolysaccharide (LPS) administration. Methods Specific pathogen‐free Sprague Dawley rats underwent intratracheal instillation of HCl and LPS. Techniques included rat weight measurement, tracheal intubation, pulmonary function monitoring, lung tissue sampling with HE staining and scoring, bronchoalveolar lavage fluid (BALF) sampling, protein and inflammatory cytokine analysis via BCA and ELISA, BALF pH determination, Evans Blue dye assessment, blood gas analysis, FITC‐dextran leakage, Western blotting, electron microscopy, survival analysis, and transcriptome sequencing with bioinformatics. Statistical analysis was performed using GraphPad Prism. Results The optimal model involved instillation of 1.5 μL/g.wt HCl (pH = 1) followed by 20 μg/g.wt LPS after 1 h. This model reproduced acute lung injury, including tissue damage, pulmonary microvascular dysfunction, inflammatory responses, hypoxemia, and impaired pulmonary ventilation, with recovery observed at 72 h. PANoptosis was confirmed, characterized by increased markers. Concentration‐dependent effects of HCl and LPS on lung damage were identified, alongside cytokine elevation and microvascular dysfunction. Conclusions This optimized model closely mimics clinical aspiration pneumonia, providing a valuable tool for studying pathophysiology and therapeutic strategies. Aspiration pneumonia was induced in Sprague Dawley rats by intratracheal instillation of hydrochloric acid (HCl, 1.5 μL/g.wt, pH = 1) followed by lipopolysaccharide (LPS, 20 μg/g.wt) after 1 h. The model reproduced hallmark features of acute lung injury, including histological lung damage, microvascular dysfunction, inflammation, hypoxemia, and impaired ventilation. Comprehensive analyses were performed, including lung histology (HE staining), bronchoalveolar lavage fluid (BALF) analysis, cytokine quantification (BCA and ELISA), pH measurement, vascular permeability (Evans Blue dye, FITC‐dextran), and blood gas analysis. Transcriptome sequencing and Western blotting revealed evidence of PANoptosis, with markers of pyroptosis, apoptosis, and necroptosis identified. Recovery from lung injury was observed at 72 h post‐induction. This model serves as a clinically relevant tool for studying aspiration pneumonia pathophysiology and therapeutic interventions.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc,Wiley
• Subject: Acute Lung Injury / Airway management / Animal models / Animals / aspiration / Bacteria / Bioinformatics / Biotechnology / Blood gas analysis / Bronchoalveolar Lavage Fluid - chemistry / Bronchus / Cytokines / Cytokines - metabolism / Dextran / disease models / Disease Models, Animal / Electron microscopy / Gram-negative bacteria / Humidity / Hydrochloric acid / Hydrochloric Acid - administration & dosage / Hypoxemia / Inflammation / Intubation / Lavage / Lipopolysaccharides / Lipopolysaccharides - administration & dosage / Lung - pathology / Lungs / Male / Microvasculature / Original / Pathogens / Pneumonia / Pneumonia, Aspiration - chemically induced / Pneumonia, Aspiration - pathology / Pneumonia, Aspiration - physiopathology / Proteins / Rats / Rats, Sprague-Dawley / Regular / Respiratory function / Sampling / Specific Pathogen-Free Organisms / Statistical analysis / Survival analysis / Trachea / Transcriptomes / Ventilators / Western blotting