The effect of macroscopic deformation on lung microstructure.
Butler, James P., Hiroshi Miki, Stephanie Squarcia, Rick A. Rogers,
and John L. Lehr.
Physiology Program, Harvard School of Public Health, Boston, MA
02115, First Dept. Internal Medicine, Tohoku University School of
Medicine, Sendai 980, Japan, Dept. of Biomedical Engineering, Boston
University, Boston, MA 02215
APStracts 3:0289A, 1996.
Using an anisotropic theory of diffuse light scattering in lungs, we
measured the fractional changes in geometric mean linear intercepts
in orthogonal directions when freshly excised rabbit lungs were
subjected to isovolume, uniaxial strains. Results from the optical
technique were compared with morphometric estimates of fractional
changes in mean linear intercepts from the same strained and
unstrained (control) lobes, with the conclusion that diffuse light
scattering is adequate to estimate changes in mean free paths in
different directions. We compared optical estimates of fractional
changes in mean linear intercepts with the macroscopic strain field
measured by displacements of pleural markers; this relationship did
not significantly differ from the line of identity. We conclude that
the microscopic strain field is closely matched to the macroscopic
strain field during uniaxial distortion. This suggests that surface
reorientation may not play a large role in the origin of the low
shear modulus of the lung, but this cannot be definitively stated
without comparison of these experimental results to specific model
predictions of the changes in mean linear intercepts in shear
deformation.
Received 14 June 1995; accepted in final form 4 June 1996.
APS Manuscript Number A633-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 28 June 96