Erk1/2 Phosphorylation Role In Asthma Mice High Airway Mucus Secretion

Objective:To establish mouse models of asthma and investigate the airway inflammation and mucus hypersecretion in asthmatic mice.Methods:Twenty BALB/c mice were randomly divided into two groups:asthmatic model group (AS) and control group (NS),with10mice in each group.Mice were sensitized on days1and13by OVA and challenged for30minutes from days19to23by5%OVA repeatedly to establish a mouse model of asthma,and the control group was sensitized and challenged with normal sodium.Total cells and differential inflammatory cells were counted in bronchoalveolar lavage fluid (BALF),the levels of IL-5and IL-32in BALF were determined by enzyme-linked immuno sorbent assay (ELISA),the pathomorphological Changes in the lung were observed by hematoxylin-eosin staining(HE),the goblet cells of airway wall and airway mucous were observed by AB-PAS staining,the expressions of Mucin-5ac(Muc5ac) protein in lung tissue were observed by immunohistochemical staining and Western blot,the expressions of Muc5ac mRNA in lung tissue were observed by real time fluorescence quantitative reverse transcription polymerase (RT-PCR).Results:Total cells, eosinophils, lymphocytes and neutrophils in BALF,the levels of IL-5and IL-32in BALF,the hyperplasia of goblet cell in airway wall.and the expressions of Muc5ac mRNA and Muc5ac in lung tissue of AS group were all significantly higher than those in the control group(P<0.01). Strong positive correlations were found with the expressions of Muc5ac and total cells, eosinophils,lymphocytes, neutrophils,IL-5,IL-32and the hyperplasia of goblet cells (r=0.990、0.979、0.986、0.947、0.960、0.987、0.992, respectively).Conclusion:A mouse model of asthma can be successfully established by repeatedly sensitized and challenged with OVA. The airway chronic inflammation and airway mucus hypersecretion were obviously observed in asthmatic mice.There were close relation between airway chronic inflammation and airway mucus hypersecretion. Objective:To investigate the role of phosphorylation of ERK1/2in airway mucus hyperse-cretion in asthmatic mice and to explore the effect of dexamethasone and U0126on the p-rotein expressions of p-ERK1/2、IL-32and Muc5ac.Methods:Fifty male BALB/c mice were randomly divided into five groups:control group(NS group), asthmatic model group(AS group),dexamethasone treatment group(AS+DEX group),U0126treatment group (AS+U0126group) and vehicle-control (dimethyl sulfoxide,DMSO) group (AS+DMSO group),with10mice in each group. Animals in intervention groups were treated with drugs before challenged.Total cells and differential inflammatory cells were counted in BALF,the levels of IL-5and IL-32in BALF were determined by ELISA,the pathomorphological Changes in the lung were observed by hematoxylin-eosin staining(HE), the goblet cells of airway wall and airway mucous were observed by alcian blue/periodic acid schiff (AB-PAS) staining, the expressions of Muc5ac mRNA in lung tissue were observed by RT-PCR,the expressions of Mucin5ac(Muc5ac)、extracellular signal-regulated kinase(ERK)、phosphorylated extracellular signal-regulated kinase(p-ERK) and IL-32in lung tissue were observed by immuneohistochemical staining and western blot.Results:The total cells, eosinophils, lymphocytes and neutrophils in BALF, the levels of IL-5,IL-32in BALF, the hyperplasia of goblet cell in airway wall,the expressions of Muc5ac、ERK、p-ERK and Muc5ac mRNA in the lung tissue of AS group were all significantly higher than those in the NS group (P<0.01), but there were not significant differences camparede with AS+DMSO group(P>0.05);each test index above in AS+DEX group and AS+U0126group was significantly lower than that in AS group (P<0.05),but still higher than NS group(P<0.05),and the differences between them were no obvious(P>0.05). Strong positive correlations were found between the expressions of Muc5ac and p-ERK1/2(r=0.983、0.996、0.903respectively). There were strong positive correlations between the expressions of p-ERK1/2and IL-32(r=0.981).Conclusion:Phosphory of ERK1/2is closely related to airway mucus hypersecretion in asthmatic mice. Dexamethasone and U0126can inhibite phosphorylation of ERKl/2,one mechanism of which may be down-regulation the expression of IL-32.