RESUMO
Objective To detect the changes of G protein-coupled inwardly rectifying potassium channels (GIRK)expression in allergic asthma model and identify the regulatory factors.Methods The E3 rat asthma models were induced by challenge with ovalbumin 14 days after immunization with ovalbumin and aluminium adjuvant.The asthma models were evaluated based on changes in lung pathomorphology and total IgE levels.The levels of GIRK1-4 mRNA and protein were detected using real time-PCR and Western blot.The anatomic sites where GIRK was expressed dominantly in the lung were identified using immunohistological staining.To identify the effects of IL-4 on the expressions of GIRK channels,GIRK 1 -4 mRNA and protein in IL-4 stimulated bronchial epithelial cell line A549 were detected by RT-PCR and Western blot.Results The levels of GIRK1-4 mRNA and protein decreased significantly in the lung in asthmatic E3 rats.The results of immunohistological staining showed that GIRK channels were dominantly expressed in airway epithelia in the lung.The levels of GIRK 1-4 mRNA and protein were down-regulated in time-and dose-dependent manners in IL-4 treated A549.Conclusion IL-4 down-regulates the expression levels of GIRK subunits in bronchial epithelia during allergic asthma.