[The characteristics of a mouse model with nasal polyp established by lipopolysaccharide]

Objective:To explore the effect of lipopolysaccharide(LPS) on the formation of nasal polyps in mice and its mechanism.Method:Five or ten μg of LPS were dropped into the nasal cavities of six to eight-week C57BL/6J mice in order to establish animal models with nasal polyps.Buried food pellets experiment was used to assess olfactory function of mice.Hematoxylin-eosin staining,olfactory marker protein(OMP),and myeloperoxidase(MPO) for neutrophil immunohistochemistry were used to observe histopathological changes in the nasal mucosa.The expression levels of cytokines,such as interferon(IFN)-γ,tumor necrosis factor(TNF)-α,IL-6 in the nasal lavage fluid,were detected by ELISA.Result:Compared to the control group,mice in the LPS groups showed significant nasal polyp formation,olfactory dysfunction,more MPO⁺ cells while less OMP⁺ cells in the nasal mucosa,as well as increased significantly levels of IFN-γ,TNF-α,and IL-6 in the nasal lavage fluids(all P<0.05).Conclusion:LPS from Gram negative bacteria alone can induce the formation of nasal polyps in mice,characterized by more neutrophils,olfactory dysfunction,and increasing Th1 cytokine.Therefore,this model is commensurate with the characteristics of primary nasal polyps found in China and other major Asian.The current study suggests that LPS may be one of the important pathogenesis of gram negative bacteria in the nasal polyps.