title: Airway and Parenchymal Strains during Bronchoconstriction in the Precision Cut Lung Slice.
abstract: The precision-cut lung slice (PCLS) is a powerful tool for studying airway reactivity, but biomechanical measurements to date have largely focused on changes in airway caliber. Here we describe an image processing tool that reveals the associated spatio-temporal changes in airway and parenchymal strains. Displacements of sub-regions within the PCLS are tracked in phase-contrast movies acquired after addition of contractile and relaxing drugs. From displacement maps, strains are determined across the entire PCLS or along user-specified directions. In a representative mouse PCLS challenged with 10(-4)M methacholine, as lumen area decreased, compressive circumferential strains were highest in the 50 μm closest to the airway lumen while expansive radial strains were highest in the region 50-100 μm from the lumen. However, at any given distance from the airway the strain distribution varied substantially in the vicinity of neighboring small airways and blood vessels. Upon challenge with the relaxant agonist chloroquine, although most strains disappeared, residual positive strains remained a long time after addition of chloroquine, predominantly in the radial direction. Taken together, these findings establish strain mapping as a new tool to elucidate local dynamic mechanical events within the constricting airway and its supporting parenchyma.
authors: School of Mathematical Sciences, University of Nottingham Nottingham, UK.
authors: Jonathan E
authors: JE
authors: Hiorns
authors: Laboratoire Interdisciplinaire de Physique, Centre National de la Recherche Scientifique, Université Grenoble AlpesGrenoble, France; Department of Molecular Pharmacology, University of GroningenGroningen, Netherlands; Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Harvard Medical SchoolBoston, MA, USA.
authors: Cécile M
authors: CM
authors: Bidan
authors: School of Mathematics, University of Manchester Manchester, UK.
authors: Oliver E
authors: OE
authors: Jensen
authors: Department of Molecular Pharmacology, University of Groningen Groningen, Netherlands.
authors: Reinoud
authors: R
authors: Gosens
authors: Department of Molecular Pharmacology, University of Groningen Groningen, Netherlands.
authors: Loes E M
authors: LE
authors: Kistemaker
authors: Department of Environmental Health, Harvard School of Public Health Boston, MA, USA.
authors: Jeffrey J
authors: JJ
authors: Fredberg
authors: Department of Environmental Health, Harvard School of Public Health Boston, MA, USA.
authors: Jim P
authors: JP
authors: Butler
authors: Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, MA, USA.
authors: Ramaswamy
authors: R
authors: Krishnan
authors: School of Mathematical Sciences, University of Nottingham Nottingham, UK.
authors: Bindi S
authors: BS
authors: Brook
keywords: PCLS; airway smooth muscle; circumferential strain; contraction; displacements; radial strain