Effects of simultaneous exposure of surfactant to serum proteins and free radicals.
Free radicals (FRs) and serum proteins have both been implicated in the pathophysiology of surfactant dysfunction during acute lung injury (ALI). This study examines how these 2 distinct mechanisms interact to contribute to altered surfactant function in this setting. Calf lung surfactant (2 mg/mL) was incubated with no additives (C = control), and with low = (LD = 125 microM FeCl2; 250 microM H2O2) and high-dose (HD = 250 microM FeCl2, 500 microM H2O2) Fenton reaction reagents to generate hydroxyl radical. Each condition was studied with (1) no protein (N); and with 25%, 200%, and 800% (weight protein/weight phospholipid) protein added as (2) bovine albumin, (3) bovine fibrinogen, (4) hemoglobin, or (5) calf serum. Lipid (LFR) and protein (PFR) free-radical products, and modifications in the tertiary structure of Surfactant Protein A (SPA) on Western blot, were observed in N LD and N HD samples. Added proteins reduced LFR and PFR changes as well as SPA structural changes. Protection was greatest for fibrinogen, hemoglobin, and serum, and least for albumin. Minimal to no dysfunction, assayed by pulsating surfactometry, was observed in all samples. These findings indicate that addition of serum proteins to surfactant at 2 mg/mL protects against, rather than promotes, FR-mediated chemical changes in surfactant lipid and protein constituents.
Marzan
Yolanda
Y
Division of Pulmonary Medicine, Brigham and Women's Hospital, and Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, USA.
Mora
Rene
R
Butler
Aaron
A
Butler
Matthew
M
Ingenito
Edward P
EP
D000818:Animals; D001798:Blood Proteins / Q000494:pharmacology*; D015153:Blotting, Western; D002417:Cattle; D004357:Drug Synergism; D005340:Fibrinogen / Q000494:pharmacology; D005609:Free Radicals / Q000378:metabolism / Q000494:pharmacology; D006454:Hemoglobins / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D017665:Hydroxyl Radical / Q000378:metabolism / Q000494:pharmacology; D066298:In Vitro Techniques; D007501:Iron / Q000494:pharmacology; D008168:Lung / Q000378:metabolism*; D011510:Proteolipids / Q000378:metabolism*; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000378:metabolism*; D012128:Respiratory Distress Syndrome / Q000378:metabolism; D012709:Serum Albumin / Q000494:pharmacology; D013500:Surface Tension / Q000187:drug effects; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
D001798:Blood Proteins; C045076:Fenton's reagent; D005609:Free Radicals; D006454:Hemoglobins; D011510:Proteolipids; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D012709:Serum Albumin; D017392:Thiobarbituric Acid Reactive Substances; D017665:Hydroxyl Radical; D005340:Fibrinogen; D006861:Hydrogen Peroxide; D007501:Iron