Document Detail

Lung and alveolar wall elastic and hysteretic behavior in rats: effects of in vivo elastase treatment.
MedLine Citation:
PMID:  12871961     Owner:  NLM     Status:  MEDLINE    
We investigated the relationship between the microscopic elastic and hysteretic behavior of the alveolar walls and the macroscopic mechanical properties of the whole lung in an in vivo elastase-treated rat model of emphysema. We measured the input impedance of isolated lungs at three levels of transpulmonary pressure (Ptp) and used a linear model to estimate the dynamic elastance and hysteresivity of the lungs. The elastance of the normal lungs increased steeply with Ptp, whereas this dependence diminished in the treated lungs. Hysteresivity decreased significantly with Ptp in the normal lungs, but this dependence disappeared in the treated lungs. To investigate the microscopic origins of these changes, the alveolar walls were immunofluorescently labeled in small tissue strips. By using a fluorescent microscope, the lengths and angular orientations of individual alveolar walls were followed during cyclic uniaxial stretching of the tissue strips. The microstrains (relative change in segment length) and changes in angle of the alveolar walls showed considerable heterogeneity, which was interpreted in terms of a network model. In the normal strips, the alveolar walls showed larger angular changes compared with the treated tissue, whereas the alveolar walls of the treated tissue tended to be more extensible. Hysteresis in the average angle change was also larger in the treated tissue than in the normal tissue. We conclude that the decreased Ptp dependence of elastance and the constant hysteresivity in the treated lungs are related to microstructural remodeling and network phenomena at the level of the alveolar walls.
Kelly K Brewer; Hiroaki Sakai; Adriano M Alencar; Arnab Majumdar; Stephen P Arold; Kenneth R Lutchen; Edward P Ingenito; Béla Suki
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.     Date:  2003-07-18
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  95     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2003 Nov 
Date Detail:
Created Date:  2003-10-13     Completed Date:  2004-06-15     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1926-36     Citation Subset:  IM    
Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA.
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MeSH Terms
Collagen / physiology
Disease Models, Animal
Emphysema / chemically induced,  physiopathology*
Microscopy, Fluorescence
Models, Biological
Pancreatic Elastase*
Pulmonary Alveoli / physiopathology*
Rats, Sprague-Dawley
Respiratory Mechanics / physiology
Stress, Mechanical
Grant Support
Reg. No./Substance:
9007-34-5/Collagen; EC Elastase

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