Establishment of a mouse model with all four clinical features of eosinophilic bronchitis.

Eosinophilic bronchitis (EB) is a clinical disease characterized by chronic cough, airway eosinophil infiltration, and responsive to steroid therapy but with the absence of airway hyperreactivity (AHR). This study established an EB mouse model with all the above features. First, 42 mice were divided into 7 groups to investigate the optimal time interval between cough and AHR detections. Afterward, 28 mice were divided into the asthma, EB, normal saline (NS), and dexamethasone (DXM) groups. Mice were challenged using nasal drops of 200 µg ovalbumin (OVA), 10 µg OVA, NS, or intraperitoneal injections of 5 mg/kg of DXM one hour prior to 10 µg OVA challenge. Airway reactivity was measured 6 h after cough was observed. The frequency of coughs in the asthma and EB groups increased significantly compared to mice in the NS group. After DXM administration, frequency of coughs was significantly decreased compared to mice in the asthma and EB groups. Lung resistance in the asthma group was significantly higher compared to mice in the NS, EB, and DXM groups. Obvious airway eosinophilic inflammation in BALF and lung tissues were observed in the asthma and EB groups, while DXM administration could attenuate airway inflammatory infiltration. In summary, we developed a mouse EB model with all four clinical features of EB by the administration of 10 µg OVA nasal drops.