Induction of nasal polyps using house dust mite and Staphylococcal enterotoxin B in C57BL/6 mice.

BACKGROUND The murine polyp model was developed previously using ovalbumin and Staphylococcus aureus enterotoxin B (SEB). Here, we established a model mimicking key aspects of chronic eosinophilic rhinosinusitis with nasal polyps using the house dust mite (HDM), a clinically relevant aeroallergen, co-administered with SEB. We assessed the inflammatory response and formation of nasal polypoid lesions in an experimental murine model using intranasal delivery of HDM and ovalbumin. METHODS After induction of HDM-induced allergic rhinosinusitis in C57BL/6 mice, SEB (10ng) was instilled into the nasal cavity of mice for eight weeks. Phosphate-buffered saline-challenged mice served as control. Histopathological changes were evaluated using haematoxylin and eosin for overall inflammation, Sirius red for eosinophils, and periodic acid-Schiff stain for goblet cells. The distribution of mast cells in mouse nasal tissue was determined by immunohistochemistry. Serum total IgE was measured using enzyme-linked immunosorbent assay. RESULTS Compared to mice treated with HDM only, the HDM+SEB-treated mice demonstrated nasal polypoid lesion formation and a significant increase in the number of secretory cells and eosinophilic infiltration. Moreover, mice challenged intranasally with HDM showed highly abundant mast cells in the nasal mucosa. In contrast, OVA+SEB-challenged mice showed a significantly lower degree of mast cell infiltration. CONCLUSION We established an in vivo model of chronic allergic rhinosinusitis with nasal polypoid lesions using HDM aeroallergen. This study demonstrated that the HDM+SEB-induced murine polyp model could be utilised as a suitable model for nasal polyps, especially with both eosinophil and mast cell infiltration.