Dexamethasone inhibits IL-33 expression in the lung in a rat model of Aspergillus fumigatus-exposed bronchial asthma / 复旦学报（医学版）

ABSTRACT

Objective To investigate the levels of IL-33 in the lung induced by Aspergillus fumigatus (A.fumigatus) exposure in bronchial asthmatic rats and the effects of dexamethasone.Methods Twenty-four Wistar rats were randomly and equally divided into group A (normal control),group B (asthma group),group C (A.fumigatus-exposed group),and group D (dexamethasone-treated group).B,C and D group were sensitized and challenged with ovalbumin (OVA) to establish asthmatic models.Then,group C and D were given A.fumigatus spores intranasally.Group D was pre-treated with dexamethasone during ovalbumin challenge.Group A was sensitized and challenged intranasally with normal saline as control.Airway hyperresponsiveness,eosinophils percentage and serum IgE levels were measured to confirm the establishment of asthmatic model.Expression of IL-33 in the lung were quantified by ELISA and qRT-PCR.Lung tissues and blood were plated on the potato dextrose agar (PDA) medium and cultivated for 24 h to measure the number of colony.Results Eosinophils percentage in bronchoalveolar lavage fluid (BALF),IgE levels in serum and IL-33 levels in the lung in group B and C were much more higher than in group A (P＜0.05),and the increasing range in group C was more obvious than group B.However,the changes of sRaw values in these groups had no statistical significance.Esosinophils percentage in BALF and IL-33 levels in the lung were significantly decreased (P＜0.05),and IgE levels in serum was slightly decreased (P＞0.05) in group D when compared with group C,but the ratio of A.fumigatus colonization in the lung was higher than group C.Conclusions Dexamethasone can inhibit the expression of IL-33 in the lung induced by A.fumigatus exposure in an asthmatic rat,but it also increases the risk of fungal colonization in the airway.Anti-IL-33 antibody treatment needs further research.