Spatial mapping of nasal polyp distribution in an ovalbumin and Staphylococcal enterotoxin B-induced murine model of chronic rhinosinusitis.

OBJECTIVES.: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogeneous inflammatory disease of the sinonasal mucosa. Although murine models provide a valuable platform for investigating disease mechanisms, variability among models limits reproducibility, in part due to the lack of standardized anatomical assessment. This study aimed to define the anatomical distribution of nasal polyps (NPs) using a five-level coronal anatomical framework and to characterize their morphological features.

METHODS.: A murine NP model was established using ovalbumin (OVA) and Staphylococcus aureus enterotoxin B (SEB). Nasal tissues were systematically analyzed across predefined coronal levels of the murine nasal cavity. Histological, immunohistochemical, and immunofluorescence analyses were performed to identify polypoid lesions, characterize their morphology, and assess inflammatory cell infiltration.

RESULTS.: Polypoid lesions were predominantly localized to coronal levels III and IV, indicating a preferential anatomical distribution. Epithelial remodeling was evident, including epithelial thickening and basal cell hyperplasia, accompanied by subepithelial fibrosis and basement membrane thickening. A type 2-skewed inflammatory profile was observed, characterized by eosinophilic infiltration, increased IL-13-positive cells, and the presence of Charcot-Leyden- like crystals.

CONCLUSION.: : Application of a five-level coronal anatomical framework enabled systematic spatial mapping of NPs within the murine CRSwNP model. This approach identified preferential localization of polypoid lesions to the mid-to-posterior nasal cavity and provides a structured method for regional anatomical assessment in future studies of murine NPs.