Abstract
BackgroundEosinophilic inflammation is a hallmark of chronic rhinosinusitis with nasal polyps. To model this disease process experimentally, nasal sensitization of mice with ovalbumin or aspergillus has been described. Here, we describe a genetically mutant mouse that develops robust spontaneous nasal eosinophilic inflammation. These mice lack the enzyme SHP-1 that down-regulates the IL-4Rα/stat6 signaling pathway. We compared nasal inflammation and inflammatory mediators in SHP-1 deficient mice (mev) and an ovalbumin-induced nasal allergy model.MethodsA novel technique of trans-pharyngeal nasal lavage was developed to obtain samples of inflammatory cells from the nasal passages of allergic and mev mice. Total and differential cell counts were performed on cytospin preparations. Expression of tissue mRNA for IL-4, IL-13, and mouse beta-defensin-1 (MBD-1) was determined by quantitative PCR. Eotaxin in the lavage fluid was assessed by ELISA.ResultsAllergic and mev mice had increased total cells and eosinophils compared with controls. Expression of IL-4 was similarly increased in both allergic and mev mice, but expression of IL-13 and eotaxin was significantly greater in the allergic mice than mev mice. Eotaxin was significantly up-regulated in both allergic rhinitis and mev mice. In both models of eosinophilic inflammation, down-regulation of the innate immune marker MBD-1 was observed.ConclusionsThe mev mice display spontaneous chronic nasal eosinophilic inflammation with potential utility for chronic rhinosinusitis with nasal polyps research. The eosinophilic infiltrate is more robust in the mev mice than allergic mice, but Th2 cytokine expression is not as pronounced. Decreased MBD-1 expression in both models supports the concept that Th2-cytokines down-regulate sinonasal innate immunity in humans, and suggests a role for mouse models in investigating the interaction between adaptive and innate immunity in the sinonasal mucosa.
Highlights
A defining characteristic of chronic rhinosinusitis with nasal polyps (CRSwNP) is the presence of an eosinophilic inflammatory infiltrate and a Th2 cytokine predominance [1]
Allergen challenge models have been created that result in chronic eosinophilic rhinosinusitis in mice [4]
Increased total cells and eosinophils in nasal airway lavage (NAL) fluids in allergic rhinitis and mev mice Because the OVA-induced allergic rhinitis model was induced in BALB/c background mice, comparisons with PBS controls were made in BALB/c mice
Summary
A defining characteristic of chronic rhinosinusitis with nasal polyps (CRSwNP) is the presence of an eosinophilic inflammatory infiltrate and a Th2 cytokine predominance [1]. Eosinophilic inflammation is a hallmark of chronic rhinosinusitis with nasal polyps. To model this disease process experimentally, nasal sensitization of mice with ovalbumin or aspergillus has been described. We describe a genetically mutant mouse that develops robust spontaneous nasal eosinophilic inflammation. These mice lack the enzyme SHP-1 that down-regulates the IL-4Ra/stat signaling pathway. We compared nasal inflammation and inflammatory mediators in SHP-1 deficient mice (mev) and an ovalbumin-induced nasal allergy model
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