Role Of TLR4/MyD88 Signaling In Airway Mucus Hypersecretion In Asthmatic Mice

Objective To investigate the inflammation and airway mucus hypersecretion in asthmatic mice treated with inhaled LPS.Methods Twenty BALB/c mice were randomly devided into three groups:asthmatic model group (AS group n=10),LPS asthmatic model group(LA group n=10),control group (NS group,n=10).asthmatic model group was sensitized and challenged with ovalbumin (OVA),LPS asthmatic model group was sensitized and challenged as the same as AS group,and was treated with inhaled LPS 1h before last two challenged,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-4 and TNF-αin BALF were determined by ELISA,the pathomorphological Changes in the lung were observed by hematoxylin-eosin staining(HE),the goblet cell of airway wall was observed by AB-PAS staining,the expression of Mucin-5ac(Muc5ac) protein in airway 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,eosinophil,monocytes and lymphocyte cells in BALF,the levels of IL-4,TNF-αin BALF,the hyperplasia of goblet cell in the airway wall,and the expression of Muc5ac mRNA and protein in lung tissue of AS group and LA group were significantly higher than those in control group(P<0.01),LAgroup was higher than AS group(P<0.05).Conclusions LPS can make airway inflammation and mucus hypersecretion higher of the asthmatic mice.Airway inflammation and mucus hypersecretion of asthmatic mice can be well built by 5%OVA. Objective To investigate the role of TLR4/MyD88 signaling in airway mucus hypersecreti-on in asthmatic mice,and the influence of intervention by Polymyxin B,SB203580 and Resveratrol.Methods Fifty BALB/c mice were randomly divided into control group(NS group, n=10), LPS asthmatic model group(LA group n=10),dexamethasone treatment group(DEX group, n=10), polymyxin B treatment group(PMB group, n=10), SB203580 treatment group(SB group,n= 10),resveratrol treatment group(RES group,n=10),vehicle-control(dimethyl sulfoxide,DMSO) group (DMSO group,n=10),Total cells and differential inflammatory cells were counted in BALF,the levels of IL-4 and TNF-a in BALF were determined by ELISA,the pathomorphological Changes in the lung were observed by hematoxylin-eosin staining(HE),the goblet cell of airway wall was observed by alcian blue/periodic acid schiff (AB-PAS) staining,the expressions of Mucin 5ac(Muc5ac) and TLR4 in lung tissue were observed by immuneohistochemical staining and western blot,the expressions of Muc5ac mRNA and TLR4 mRNA in lung tissue were observed by RT-PCR.Results The total cells, eosinophil, monocytes and lymphocyte cells in BALF, the levels of IL-4,TNF-a in BALF,the goblet cell of airway wall,the expression of Muc5ac and TLR4 positive staining IOD in the airway and the expression of Muc5ac mRNA and TLR4 mRNA lung tissue significantly decreased in PMB,SB,RES and DEX groups which compared with LA group and DMSO group (P<0.05);the defferences between PMB,SB,RES and DEX groups were not significant (P>0.05)Conclusions TLR4/MyD88 signaling may induce airway inflammation,upgrate Muc5ac mRNA and Muc5ac hypersecretion in airway of asthmatic mice.PMB,SB203580,RES may inhibit inflammation and mucus hypersecretion in airway of mice with asthma,which were mediated by TLR4/MyD88 signaling.