The effects of imiquimod on the level of BALF IL-12, IL-13 and sera IgE in asthmatic murine

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Objective To observe the effects of aerosol imiquimod on the level of Interleukin-12(IL-12) and interleukin-13(IL-13) in bronchial alveolar lavage fluid(BALF) and serum immunoglobulin E( IgE ) level in mouse asthma models. Methods Thirty BALB/c mice were divided into 3 groups, control group, asthma group and imiquimod group, ten in each group.The asthma group and imiquimod group were established by sensitization and challenge with ovalbumin (OVA), imiquimod group was interfered with aerosol imiquimod 30 min before challenge.Serum in each group was collected by excising eyeball 24 h after the last challenge.The level of IgE in serum was measured by ELISA.Bronchoalveolar lavage fluid (BALF) was performed, and total cell counts, cell differential were examined.The level of IL-12 and IL-13 in BALF was measured by ELISA and total cell counts, cell differential were examined in BALF.The inflammation changes of lung was observed by HE staining. Results (1)By hematoxylin-eosin(HE) staining, the result of asthma mice were small airway wall thickening, secretion increased, epithelial cells fall off, arranging disorderly, and submucosal had plenty of inflammatory cells infiltration, mainly with lymphocytes.But imquimod group attenuated the airway inflammation of asthmatic mice.(2)Total cell counts and all kinds of inflammatory cells of asthma group were increased greatly compared with normal group; Eosinophil and lymphocyte cells were much lower in imquimod group than those in asthma group (P<0.05). (3) The level of IL-13 in BALF and the level of IgE in serum in imiquimod group was obviously higher than that in control group, IL-13 level were positively correlated with IgE level(r=0.774, P<0.05), but imiquimod group was greatly decreased compared with control group and increased in comparison with that in group A; The level of IL-12 in asthma group was reduced and the level of IgE was increased compared with normal group.IL-12 level in imiquimod group was evidently higher and IgE level was lower than that in asthma group.IL-12 level negatively correlated with IgE level(r=-0.802, P<0.05). Conclusion Imiquimod aerosol inhalation may up-regulate the level of Th1 chemokine IL-12, down-regulates the level of Th2 chemokine IL-13 and decrease the level of IgE in serum so that it may suppress antigen-induced airway inflammation. Key words: Asthma; IgE; Imiquimod