Physiological and inflammatory response to instillation of an oxidized surfactant in a rat model of surfactant deficiency

• Published in: Journal of applied physiology (1985) 2004-05, Vol.96 (5), p.1674-1680
• Main Authors: Bailey, Timothy C, Da Silva, Keith A, Lewis, James F, Rodriguez-Capote, Karina, Possmayer, Fred, Veldhuizen, Ruud A. W
• Format: Article
• Language: English
• Subjects: Animals; Arteries; Biological and medical sciences; Bronchoalveolar Lavage Fluid - chemistry; Dose-Response Relationship, Drug; Drug Combinations; Fundamental and applied biological sciences. Psychology; Instillation, Drug; Interleukin-6 - metabolism; Lipids; Lung - drug effects; Lung - metabolism; Lungs; Male; Oxidation; Oxygen - blood; Partial Pressure; Pneumonia - chemically induced; Proteins; Pulmonary Surfactant-Associated Protein A - pharmacology; Pulmonary Surfactant-Associated Proteins - administration & dosage; Pulmonary Surfactant-Associated Proteins - pharmacology; Pulmonary Surfactants - metabolism; Rats; Rats, Sprague-Dawley; Respiratory system; Rodents; Surfactants; Tumor Necrosis Factor-alpha - metabolism
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.01143.2003

Departments of 1 Physiology and Pharmacology, 2 Biochemistry, and 3 Medicine, Lawson Health Research Institute, University of Western Ontario, London, Ontario, Canada N6A 4V2 Submitted 22 October 2003 ; accepted in final form 25 December 2003 Pulmonary surfactant is a mixture of phospholipids ( 90%) and surfactant-associated proteins (SPs) ( 10%) that stabilize the lung by reducing the surface tension. One proposed mechanism by which surfactant is altered during acute lung injury is via direct oxidative damage to surfactant. In vitro studies have revealed that the surface activity of oxidized surfactant was impaired and that this effect could be overcome by adding SP-A. On the basis of this information, we hypothesized that animals receiving oxidized surfactant preparations would exhibit an inferior physiological and inflammatory response and that the addition of SP-A to the oxidized preparations would ameliorate this response. To test this hypothesis, mechanically ventilated, surfactant-deficient rats were administered either bovine lipid extract surfactant (BLES) or in vitro oxidized BLES of three doses: 10 mg/kg, 50 mg/kg, or 10 mg/kg + SP-A. When instilled with 10 mg/kg normal surfactant, the rats had a significantly superior arterial P O 2 responses compared with the rats receiving oxidized surfactant. Interestingly, increasing the dose five times mitigated this physiological effect, and the addition of SP-A to the surfactant preparation had little impact on improving oxygenation. There were no differences in alveolar surfactant pools and the indexes of pulmonary inflammation between the 10 mg/kg dose groups, nor was there any differences observed between either of the groups supplemented with SP-A. However, there was significantly more surfactant and more inflammatory cytokines in the 50 mg/kg oxidized BLES group compared with the 50 mg/kg BLES group. We conclude that instillation of an in vitro oxidized surfactant causes an inferior physiological response in a surfactant-deficient rat. alveolar metabolism; biophysical function and acute lung injury Address for reprint requests and other correspondence: T. C. Bailey, Lawson Health Research Institute, H417 268 Grosvenor St., London, ON, Canada N6A 4V2 (E-mail: tbailey2{at}uwo.ca ).