title: Effects of glucocorticoid on IL-13-induced Muc5ac expression in airways of mice.
abstract: To study the effects of glucocorticoid on the IL-13-induced Muc5ac expression in airways of mice, and investigate its role in mucus secretion of airways, 24 pathogen-free BALB/c mice were randomly divided into 3 groups. IL-13 group received an nasal instillation of 100 microg of recombinant murine IL-13 solution on days 1, 3 and 5. In dexamethasone group, dexamethasone (0.5 mg/kg) was administered intraperitoneally 24 h before and 1 h before the first instillation of IL-13 and on 4 consecutive days (day 0 to day 5, 6 consecutive days in total), while control group was not treated with IL-13 or dexamethasone. Bronchoalveolar lavage fluid (BALF) was collected and eosinophils were counted, and expression of Muc5ac mRNA and protein in lungs were detected by reverse transcription-polymerase chain reaction (RT-PCR) technology and immunohistochemical assay respectively. Our results showed that the number of mice, with positve Muc5ac protein expression, expression of Muc5ac mRNA and eosinophils in BALF after IL-13 treatment were all significantly higher than that of control group (all P<0.01). Despite eosinophils reduced (P<0.01), the number of mice with positive Muc5ac protein expression, expression of Muc5ac mRNA afterdexamethasone treatment didn't decreas significantly as compared with that of IL-13 group. It is concluded that IL-13 can up-regulate the expression of Muc5ac mRNA and protein, which may play a pivotal role in the mucus overproduction of airways. Dexamethasone can suppress IL-13-induced eosinophilic infiltration in lung but can't inhibit the mucus overproduction.
authors.affiliation: Research Laboratory of Respiratory Diseases, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Liu
authors.forename: Zhenxiang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Yongjian
authors.initials: Y
authors.lastname: Xu
authors.forename: Lihua
authors.initials: L
authors.lastname: Xing
authors.forename: Huilan
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D003907:Dexamethasone / Q000494:pharmacology*; D018793:Interleukin-13 / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D055271:Mucin 5AC; D009077:Mucins / Q000096:biosynthesis* / Q000235:genetics; D009093:Mucus / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011897:Random Allocation; D012137:Respiratory System / Q000378:metabolism*
chemical_list: D018793:Interleukin-13; C524679:Muc5ac protein, mouse; D055271:Mucin 5AC; D009077:Mucins; D012333:RNA, Messenger; D003907:Dexamethasone