| Effects of Corticosteroid Treatment on Airway Inflammation, Mechanics, and Hyperpolarized 3He Magnetic Resonance Imaging in an Allergic Mouse Model. | |
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MedLine Citation:
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PMID: 22241062 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The purpose of this study was to assess the effects of corticosteroid therapy on a murine model of allergic asthma using hyperpolarized (3)He Magnetic Resonance Imaging (MRI) and respiratory mechanics measurements before, during, and after methacholine (MCh) challenge. Three groups of mice were prepared, consisting of Ovalbumin sensitized/Ovalbumin challenged (Ova/Ova, n=5), Ova/Ova-challenged but treated with the corticosteroid Dexamethasone (Ova/Ova+Dex, n=3), and Ovalbumin-sensitized/saline-challenged (Ova/PBS, n=4) control animals. All mice underwent baseline 3D (3)He MRI, then received a MCh challenge while ten 2D (3)He MR images were acquired for 2 minutes, followed by post-MCh (3)D 3He MRI. Identically treated groups underwent respiratory mechanics evaluation (n=4/group) and inflammatory cell counts (n=4/group). Ova/Ova animals exhibited predominantly large whole lobar defects at baseline, with significantly higher ventilation defect percentage (VDP=19±4%) than Ova/PBS (+2±1%, p=0.01) animals. Such baseline defects were suppressed by Dexamethasone (0%, p=0.009). In the Ova/Ova group, MCh challenge increased VDP on both 2D (+30±8%) and 3D MRI scans (+14±2%). MCh-induced VDP changes were diminished in Ova/Ova+Dex animals on both 2D (+21±9%, p=0.63), and 3D scans (+7±2%, p=0.11), and also in Ova/PBS animals on 2D (+6±3%, p=0.07) and 3D (+4±1%, p=0.01) scans. Because MCh challenge caused near complete cessation of ventilation in four of five Ova/Ova animals, even as large airways remained patent, implies that small airway (< 188 μm) obstruction predominates in this model. This corresponds with respiratory mechanics observations that MCh challenge significantly increases elastance and tissue damping, but only modestly affects Newtonian airway resistance. |
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Authors:
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Abraham C Thomas; S Sivaram Kaushik; John Nouls; Erin N Potts; Deborah M Slipetz; William Michael Foster; Bastiaan Driehuys |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-1-12 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: - ISSN: 1522-1601 ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
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Created Date: 2012-1-13 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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1Duke University Medical Center. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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