Induction of a type 2 inflammatory chronic rhinosinusitis in C57BL/6 mice.

Background: Eosinophilic chronic rhinosinusitis (CRS) has been widely studied for its intractability and high recurrence rate. It can be divided into pure and mixed type 2 CRS subtypes. Mouse models that reflect pure type 2 inflammation of CRS are lacking.

Objective: This study aims to establish a relatively pure type 2 CRS mouse model and compare it with 2 mixed type 2 CRS models.

Methods: Three mouse CRS models were constructed: (1) aerosol ovalbumin (OVA) + aspergillus oryzae-derived protease (AP); (2) intranasal OVA + AP; (3) Intraperitoneal then intranasal OVA + AP (n = 10 per group). Nasal, lung symptoms, IgE, inflammatory cells, cytokines, and remodeling factors were evaluated.

Results: Histological and micro-computed tomography showed inflammation, polyps, and opacification in all 3 experimental groups. The aerosol group had significantly increased local eosinophils and type 2 cytokines, while other types of cytokines showed no noticeable change. The nasal instillation groups also showed elevated other inflammatory factors and tissue polypoid changes were more pronounced. More severe pulmonary inflammation was observed with aerosol delivery.

Conclusion: Aerosol inhalation mouse model is superior for studying nasal relatively pure type 2 inflammation and lower airway comorbidities.