title: Mechanical ventilation of isolated rat lungs changes the structure and biophysical properties of surfactant.
abstract: Mechanical ventilation is an essential but potentially harmful therapeutic intervention for patients with acute lung injury. The objective of this study was to investigate the effects of mechanical ventilation on large-aggregate surfactant (LA) structure and function. Isolated rat lungs were randomized to either a nonventilated control group, a relatively noninjuriously ventilated group [1 h, 10 ml/kg tidal volume, 3 cmH(2)O positive end-expiratory pressure (PEEP)], or an injuriously ventilated group (1 h, 20 ml/kg tidal volume, 0 cmH(2)O PEEP). Injurious ventilation resulted in significantly decreased lung compliance compared with the other two groups. LA structure, as determined by electron microscopy, revealed that LA from the injurious group had significantly lower amounts of organized lipid-protein structures compared with LA obtained from the other groups. Analysis of the biophysical properties by using a captive bubble surfactometer demonstrated that adsorption and surface tension reduction were significantly impaired with LA from the injuriously ventilated lungs. We conclude that the injurious mechanical ventilation impairs LA function and that this impairment is associated with significant morphological alterations.
authors.affiliation: Lawson Health Research Institute and Department of Physiology, University of Western Ontario, London, Ontario, Canada N6A 4V2. rveldhui@uwo.ca
authors.forename: Ruud A W
authors.initials: RA
authors.lastname: Veldhuizen
authors.forename: Blayne
authors.initials: B
authors.lastname: Welk
authors.forename: Rob
authors.initials: R
authors.lastname: Harbottle
authors.forename: Stephen
authors.initials: S
authors.lastname: Hearn
authors.forename: Kaushik
authors.initials: K
authors.lastname: Nag
authors.forename: Nils
authors.initials: N
authors.lastname: Petersen
authors.forename: Fred
authors.initials: F
authors.lastname: Possmayer
mesh_terms: D000327:Adsorption; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D066298:In Vitro Techniques; D008168:Lung / Q000502:physiology* / Q000648:ultrastructure; D008170:Lung Compliance; D055370:Lung Injury; D008297:Male; D011175:Positive-Pressure Respiration; D011663:Pulmonary Surfactants / Q000737:chemistry* / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012121:Respiration, Artificial / Q000009:adverse effects / Q000379:methods; D013500:Surface Tension; D013990:Tidal Volume; D014947:Wounds and Injuries / Q000209:etiology / Q000473:pathology / Q000503:physiopathology
chemical_list: D011663:Pulmonary Surfactants