Intranasal Aspergillus fumigatus exposure induces eosinophilic inflammation and olfactory sensory neuron cell death in mice

OBJECTIVE: To determine the effects of eosinophilic inflammation on olfactory sensory neuron cell death. STUDY DESIGN: Mice were sensitized to intranasal Aspergillus fumgatus extract and subsequently challenged acutely or chronically with the same allergen. The olfactory neuroepithelium was assessed for immunohistochemical evidence of apoptosis and inflammation. RESULTS: Sensitized mice challenged with allergen demonstrated elevated eosinophil infiltration of the respiratory and olfactory mucosae, with olfactory sensory neuron apoptosis. Remarkably. massive neuronal apoptosis without eosinophil infiltration occurred in nonsensitized mice after a single dose of extract. CONCLUSION: Intranasal sensitization with A fumigatus results in a model with multifactorial effects. Protocols using A fumigatus to induce allergic rhinitis may need modification to allow confident interpretation. SIGNIFICANCE: Fungal allergens may contribute to anosmia through the induction of olfactory sensory neuron apoptosis, with and without prior sensitization. (c) 2008 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.