Establishment of a mouse model of acid aspiration-induced lung injury

Lei GUO; Longding LIU; Junjie MEI

ABSTRACT

Objective To establish a non-traumatic mouse model of acid aspiration-induced lung injury which al-lows longitudinal studies.Method C57BL/6 mice were anesthetized and orotracheally intubated with a 20 gauge angio-catheter guided by optical fiber.The mice were subsequently placed in the right lateral decubitus position and external com-pression to the left lung was manually applied.A polyethylene catheter was advanced into the right lung and used to instill either hydrochloric acid (2.5μL/g, 0.1 mol/L, pH 1.5) or saline as control.Then the mice were recovered with supple-mental oxygen for 4 hours.The pulmonary physiological function and survival of mice within 2 weeks after surgery were as-sessed.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 oxy-gen 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 bronchoalve-olar 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.