title: Morpho-functional analysis of lung tissue in mild interstitial edema.
abstract: Mild pulmonary interstitial edema was shown to cause fragmentation of interstitial matrix proteoglycans. We therefore studied compartmental fluid accumulation by light and electron microscopy on lungs of anesthetized rabbits fixed in situ by vascular perfusion after 0.5 ml.kg(-1).min(-1) iv saline infusion for 180 min causing approximately 6% increase in lung weight. Morphometry showed that a relevant portion (44%) of extravascular fluid is detected early in the alveolar septa, 85% of this fluid accumulating in the thick portion of the air-blood barrier. The arithmetic mean thickness of the barrier increased in interstitial edema from 1.06 +/- 0.05 (SE) to 1.33 +/- 0.06 microm. The harmonic mean thickness increased from 0.6 +/- 0.03 to 0.86 +/- 0.07 microm, mostly due to thickening of the thin portion causing an increase in gas diffusion resistance. Despite some structural damage, the air-blood barrier displays a relatively high structural resistance providing a safety factor against the development of severe edema. It is suggested that the increase in extra-alveolar perivascular space occurs as a consequence of fluid accumulation in the air-blood barrier.
authors.affiliation: Department of Experimental Medicine, University of Milano-Bicocca, Via Cadore 48, 20052 Monza, Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Conforti
authors.forename: Carla
authors.initials: C
authors.lastname: Fenoglio
authors.forename: Graziella
authors.initials: G
authors.lastname: Bernocchi
authors.forename: Ombretta
authors.initials: O
authors.lastname: Bruschi
authors.forename: Giuseppe A
authors.initials: GA
authors.lastname: Miserocchi
mesh_terms: D000818:Animals; D001485:Basement Membrane / Q000473:pathology / Q000502:physiology; D001825:Body Fluid Compartments / Q000502:physiology; D003094:Collagen / Q000502:physiology; D004058:Diffusion; D005109:Extracellular Matrix / Q000502:physiology; D015633:Extravascular Lung Water / Q000502:physiology; D006400:Hematocrit; D008168:Lung / Q000473:pathology / Q000503:physiopathology; D009929:Organ Size; D011509:Proteoglycans / Q000502:physiology; D011654:Pulmonary Edema / Q000473:pathology* / Q000503:physiopathology*; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D011817:Rabbits
chemical_list: D011509:Proteoglycans; D003094:Collagen