Document Detail


High-resolution spatial measurements of ventilation-perfusion heterogeneity in rats.
MedLine Citation:
PMID:  20203067     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study was designed to validate a high-resolution method to measure regional ventilation (VA) in small laboratory animals, and to compare regional Va and perfusion (Q) before and after methacholine-induced bronchoconstriction. A mixture of two different colors of 0.04-microm fluorescent microspheres (FMS) was aerosolized and administered to five anesthetized, mechanically ventilated rats. Those rats also received an intravenous injection of a mixture of two different colors of 15-microm FMS to measure regional blood flow (Q). Five additional rats were labeled with aerosol and intravenous FMS, injected with intravenous methacholine, and then relabeled with a second pair of aerosol and intravenous FMS colors. After death, the lungs were reinflated, frozen, and sequentially sliced in 16-microm intervals on an imaging cryomicrotome set to acquire signal for each of the FMS colors. The reconstructed lung images were sampled using randomly placed 3-mm radius spheres. Va within each sphere was estimated from the aerosol fluorescence signal, and Q was estimated from the number of 15-microm FMS within each sphere. Method error ranged from 6 to 8% for Q and 0.5 to 4.0% for Va. The mean coefficient of variation for Q was 17%, and for Va was 34%. The administration of methacholine altered the distribution of both VA and Q within lung regions, with a change in Va distribution nearly twice as large as that seen for Q. The methacholine-induced changes in Va were not associated with compensatory shifts in Q. Cryomicrotome images of FMS markers provide a high-resolution, anatomically specific means of measuring regional VA/Q responses in the rat.
Authors:
H Thomas Robertson; Melissa A Krueger; Wayne J E Lamm; Robb W Glenny
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Validation Studies     Date:  2010-03-04
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  108     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2010 May 
Date Detail:
Created Date:  2010-05-05     Completed Date:  2010-08-12     Revised Date:  2011-07-28    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1395-401     Citation Subset:  IM    
Affiliation:
Department of Medicine, University of Washington, and University Hospital, Box 356522, Seattle, WA 98195-6522, USA. tomrobt@u.washington.edu
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MeSH Terms
Descriptor/Qualifier:
Administration, Inhalation
Aerosols
Animals
Bronchoconstriction
Bronchoconstrictor Agents / administration & dosage
Fluorescent Dyes / administration & dosage
Frozen Sections
Image Processing, Computer-Assisted
Injections, Intravenous
Lung / blood supply*,  drug effects,  physiology*
Male
Methacholine Chloride / administration & dosage
Microspheres
Pulmonary Circulation*
Rats
Rats, Sprague-Dawley
Regional Blood Flow
Reproducibility of Results
Respiration, Artificial
Ventilation-Perfusion Ratio*
Grant Support
ID/Acronym/Agency:
HL073598/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Aerosols; 0/Bronchoconstrictor Agents; 0/Fluorescent Dyes; 62-51-1/Methacholine Chloride
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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