Fig. 1

The induction of neutrophilic airway inflammation in mice. a Schematic diagram showing the strategy of allergen sensitization and challenge for the mouse model of neutrophilic airway inflammation. The mice were sensitized with 100 μg OVA and 0.1 μg LPS on day 0 and 7, and then were challenged with 5% OVA aerosols for 40 min on day 14. The mice were finally sacrificed at 4 h, 24 h, 48 h or 72 h post-challenge (n = 3). Representative H&E staining (b) and PAS staining (c) of lung tissues for neutrophilic and eosinophilic airway inflammation (× 200). Almost no PAS-positive cells were observed in the epithelial cells for neutrophilic airway inflammation while obvious PAS-positive cells were found in eosinophilic airway inflammation. d Representative Diff-Quik staining for inflammation cells present in BALF for neutrophilic airway inflammation and eosinophilic airway inflammation (× 200). For the neutrophilic airway inflammation, the neutrophils (blue arrows) but not the eosinophils (red arrows) were the dominant inflammatory cells in the BALF, and only a few macrophages (black arrows) and lymphocytes (yellow arrows) were observed. For the eosinophilic airway inflammation, the eosinophils were the dominant inflammatory cells in the BALF. e The statistical tendency of inflammation score and IL-17A level in the BALF after challenge, and the levels at 4 h and 48 h were further compared and analyzed. **P < 0.01 by t test. Abbreviations: BALF bronchoalveolar lavage fluids, i.n. intranasally, LPS lipopolysaccharide, ns not significant, OVA ovalbumin