ESTABLISHMENT OF EOSINOPHILIC BRONCHITIS MOUSE MODEL WITH NONINVASIVE LUNG FUNCTION TEST

Background and Aims: Eosinophilic bronchitis (EB) is a disease characterized by chronic cough and airway eosinophil infiltration, responsive to hormone therapy but without airway hyperreactivity (AHR). To date, there is no mouse model established with those whole features of EB. Methods: 28 mice were divided into the normal saline (NS), asthma (AS), EB, and dexamethasone (DXM) groups. The AS group received 200 μg/50 μL while the EB and DXM groups received 10 μg/50 μL OVA intranasal stimulation, while the NS group with normal saline. The DXM group received intraperitoneal injection of 5 mg/kg of DXM 1 h before stimulation. After model establishment, the cough sensitivity of the mice was evaluated. Airway reactivity with noninvasive lung function test was assessed 6h later. The percentages of eosinophils (EOS%) in the bronchoalveolar lavage fluid (BALF) and the pathological changes of the lung tissues were observed in all groups. Results: The cough sensitivity was significantly increased in the AS, EB, and DXM groups compared to the NS group (P < 0.05). After DXM treatment, the cough sensitivity was significantly decreased compared to the AS and EB groups (P < 0.05). After stimulation with methacholine (Mch; 12.5, 25 and 50 mg/mL), the Penh was significantly higher in the AS group than in the other 3 groups (P < 0.05). No significant difference was found among the other 3 groups at any Mch concentration. The BALF and pathological results showed that the mice in the AS and EB groups had obvious airway eosinophilic inflammation and that DXM attenuated the airway inflammatory infiltration in the EB mice. Conclusion: Small OVA dose (10 μg) via intranasal stimulation successfully established a mouse EB model with following 4 features: increase in the number of coughs, airway eosinophilic inflammation, no AHR, and responsiveness to hormone treatment. EB mouse model established with noninvasive lung function test is in favor of studies needing repeated detection.