Role Of TSLP In Airway Mucus Hypersecretion In Asthmatic Mice

Objective:To Preparate a mouse asthmatic model in the ovalbumin (OVA) sensitized and challenged BALB/c mice.Methods:Twenty BALB/c mice were randomly devided into asthma model group (AS group, n=10) and normal sodium control group (NS group, n=10). Mice were sensitized on days1and13by OVA and challenged from days19to23by5%OVA(or with normal sodium as a control) repeatedly. Mice were killed at24hours after the final OVA challenge. Total cells and differential inflammatory cells were counted in bronchoalveolar lavage fluid (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 hyperplasia or metaplasia of goblet cells in airway wall and the degree of mucus secretion were observed by alcian blue/periodic acid schiff (AB-PAS) staining, the collagen hyperplasia of bronchial tract was observed by Van Gieson(VG) staining, the expression of Mucin5ac (Muc5ac) and IL-32in lung tissue were observed by immunohistochemical(IHC) staining, the expressions of Muc5ac mRNA and protein in lung tissue were observed by real time fluorescence quantitative reverse transcription polymerase (PCR) and Western blot respectively.Results:The asthmatic pathomorphological changes in the lung were obviously observed in AS group. Each counts of total cells, eosinophile, lymphocyte and neutrophile in BALF, the levels of IL-5, IL-32in BALF, the airway inflammatory pathological score, the hyperplasia or metaplasia of goblet cells in the airway wall and the degree of mucus secretion, the collagen hyperplasia of bronchial tract, the expression of Muc5ac protein, IL-32protein and Muc5ac mRNA in lung tissue of AS group were obviously higher than those in control group(P<0.05).Conclusion:AN animal asthmatic model was successfully duplicated in the OVA sensitized and challenged BALB/c mice. The airway chronic inflammation, goblet cells hyperplasia or metaplasia and airway mucus hypersecretion were obviously observed in asthmatic mice. Moreover, airway chronic inflammation and airway mucus hypersecretion were related closely. Objective:To investigate the role of TSLP in airway mucus hypersecretion in asthmatic mice, and the influence of intervention by rosiglitazone and dexamethasone.Methods:Forty BALB/c mice were randomly divided into normal sodium control group(NS group, n=10), asthmatic model group(AS group, n=10), rosiglitazone treatment group(AS+ROS group, n=10), dexamethasone treatment group(AS+DEX group, n=10). In NS group and AS group, the sensitive and challenge methods were the same as the part one. In the case of treatment with rosiglitazone(5mg/kg per day), it was given by oral gavage seven times on days17to23, beginning2days before the first challenge, and from days19to23before half hour of challenge repeatedly. Mice were treated with dexamethasone(2mg/kg per day) from days19to23before half hour of challenge repeatedly in AS+DEX group. Total cells and differential inflammatory cells were counted in BALF, the levels of IL-5in BALF was determined by ELISA, the pathomorphological changes in the lung were observed by HE, the hyperplasia of goblet cells in airway wall and the degree of mucus secretion were observed by AB-PAS staining, the collagen hyperplasia of bronchial tract was observed by VG staining, the expression of Muc5ac, TSLP, CD11c in lung tissue and CD11c in spleen tissue were observed by IHC staining, the expressions of Muc5ac, TSLP mRNA and protein in lung tissue were observed by RT-PCR and Western blot respectively.Results:Each counts of total cells, eosinophile, lymphocyte and neutrophile in BALF, the levels of IL-5in BALF, the airway inflammatory pathological score, the hyperplasia or metaplasia of goblet cells in the airway wall and the degree of mucus secretion, the collagen hyperpalsia of bronchial tract, the expression of Muc5ac protein, TSLP protein, CD11c protein in lung tissue and CD11c protein in spleen tissue, Muc5ac and TSLP mRNA in lung tissue of AS group were obviously higher than those in control group, AS+DEX group and AS+ROS group(P<0.05).Conclusion:TSLP was highly expressed in the bronchial epithelial cells of murine asthma model. TSLP may induce CD11c+DCs to active CD4+T cells and produce T helper type2(Th2) responses, so that aggravating the airway inflammation, upgrating Muc5ac mRNA and Muc5ac protein hypersecretion and promoting mucus hypersecretion in airway of asth-matic mice. Rosiglitazone or dexamethasone may inhibit inflammation and mucus hypers-ecretion in airway of mice with asthma, which were mediated by depressing expression of TSLP and inhibiting the production of Th2cytokines.