Abstract:Objective To establish a non-traumatic mouse model of acid aspiration-induced lung injury which allows longitudinal studies. Method C57BL/6 mice were anesthetized and orotracheally intubated with a 20 gauge angiocatheter guided by optical fiber. The mice were subsequently placed in the right lateral decubitus position and external compression to the left lung was manually applied. A polyethylene catheter was advanced into the right lung and used to instill either hydrochloric acid (2.5 μL/g, 0.1 mol/L, pH 1.5) or saline as control. Then the mice were recovered with supplemental oxygen for 4 hours. The pulmonary physiological function and survival of mice within 2 weeks after surgery were assessed. Results Methylene blue instillation showed that the staining fluid went into the right lung of the non-traumatically intubated mice. The survival rate of the mice with non-traumatic instillation was 80%, statistically significantly higher than those with tracheostomy instillation. Histological examination and lung function (wet/dry ratio, elastance and arterial oxygen saturation) assay demonstrated that acid instillation caused a profound pathological changes and functional impairment of the lung. Besides, acid aspiration into the mouse lung caused a significant increase in neutrophil infiltration in mouse pulmonary alveoli and high concentrations of inflammatory factors (TNF-α, IL-6, CXCL1 and CXCL2) in the bronchoalveolar lavage fluid. Conclusions We successfully established a mouse model of acid aspiration-induced lung injury, which may serve as a reliable model for longitudinally studying pulmonary immune-inflammatory mechanism in humans.