Mechanical ventilation of isolated septic rat lungs: effects on surfactant and inflammatory cytokines.
Nakamura, Tomoo, Jaret Malloy, Lynda McCaig, Li-Juan Yao, Mariamma Joseph, Jim Lewis, and Ruud Veldhuizen.
Departments of Physiology, Medicine, and Pathology, Lawson Health Research Institute, St. Joseph's Health Centre, University of Western Ontario, London, Ontario, Canada N6A 4V2
APStracts 8:0274A, 2001.
The effects of mechanical ventilation (MV) on the surfactant system and cytokine secretion were studied in isolated septic rat lungs. At 23 h after sham surgery or induction of sepsis by cecal ligation and perforation (CLP), lungs were excised and randomized to one of three groups: 1) a nonventilated group, 2) a group subjected to 1 h of noninjurious MV (tidal volume = 10 ml/kg, positive end-expiratory pressure = 3 cmH2O), or 3) a group subjected to 1 h of injurious MV (tidal volume = 20 ml/kg, positive end-expiratory pressure = 0 cmH2O). Nonventilated sham and CLP lungs had similar compliance, normal lung morphology, surfactant, and cytokine and induced morphological change. Injurious ventilation decreased compliance, altered surfactant, increased cytokines, and induced morphological changes compared with nonventilation in sham and CLP lungs. In these lungs, the surfactant system was similar in sham and CLP lungs; however, tumor necrosis factor-a and interleukin-6 levels were significantly higher in CLP lungs. We conclude that injurious ventilation altered surfactant independent of sepsis and that the CLP lungs were predisposed to the secretion of larger amounts of cytokines because of ventilation.
Received 16 October 2000; accepted in final form 13 March 2001
APS Manuscript Number A995-0.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 18 June 2001