Establishment of a chronic aspiration pneumonia mouse model using oropharyngeal aspiration of food suspension

Abstract Background Aspiration pneumonia (AP) is a prevalent and life‐threatening pulmonary disease resulting from repeated aspiration of exogenous materials such as food or gastric contents. However, most existing animal models simulate only acute injury and fail to reproduce the chronic pathological features observed in patients. This study aimed to establish a stable and clinically relevant chronic AP mouse model. Methods First, four inhalation techniques including unilateral vagotomy (UV), intranasal inoculation (IN), intratracheal instillation (IT), and oropharyngeal aspiration (OA) were evaluated for model establishment in mice. The optimal method OA was applied to administer normal saline (NS), food suspension (FS), or gastric contents (GC) once weekly. Disease progression was evaluated at 2, 4, and 8 weeks. Lung injury was evaluated by tracer distribution, histopathology, cytokine profiling, transcriptomic analysis, and micro‐computed tomography (micro‐CT). Results OA achieved stable pulmonary delivery. Both FS and GC induced lung injury. However, 8‐week FS exposure resulted in more severe and persistent damage, characterized by increased alveolar–capillary barrier permeability and elevated cytokine and chemokine levels. Histology showed FS‐specific obstructive bronchiolitis with retained food particles, closely mimicking human aspiration pneumonia. Micro‐CT revealed gravity‐dependent pulmonary consolidation, most evident in the FS group. Transcriptomic analysis indicated activation of neutrophil extracellular traps (NETs) formation during chronic AP progression. Conclusions This OA‐based FS model reproduced the key pathological and imaging features of human chronic AP and implicated NETs in the disease progression. It provides a robust platform for mechanistic investigation and therapeutic development.