title: Catalase pretreatment attenuates oleic acid-induced edema in isolated rabbit lung.
abstract: Because reactive O2 metabolites have been demonstrated to be potent mediators of vascular dysfunction and are synthesized by lung tissue, their involvement as mediators of oleic acid (OA)-induced pulmonary edema in the isolated Krebs-perfused rabbit lung was assessed. Injection of OA (0.1 ml) into the pulmonary artery after vehicle pretreatment induced marked increases in lung weight [50.4 +/- 13.9 vs. 4.2 +/- 2.0 (SE) g 45 min after OA or vehicle, respectively, P less than 0.05], an index of pulmonary edema, and airway pressure. OA also caused a significant though minimal increase in pulmonary arterial pressure. Pretreatment with catalase (1,000 U/ml), a scavenger of H2O2, significantly (P less than 0.05, Friedman's) attenuated the increases in lung weight (50.4 +/- 13.9 vs. 15.1 +/- 4.9 g), airway pressure, and pulmonary arterial pressure. In contrast to catalase, pretreatment with Cu-tryptophan (40 microM), a lipid-soluble scavenger of superoxide, provided no protective effect by itself, nor was there any potentiation of protection when combined with catalase. Further evidence implicating O2 metabolites in OA-induced edema was obtained by electron paramagnetic resonance (EPR) spectroscopy of perfusate samples to which the spin trap, sodium 3,5-dibromo-4-nitrosobenzenesulfonate (10 mM), was added. Analysis of these samples revealed the presence of free radicals after OA. Pretreatment with catalase (1,000 U/ml) and superoxide dismutase (250 U/ml) attenuated the EPR signal, indicating that proximal formation of O2 free radicals was in part responsible for the signal. These results suggest that reactive O2 metabolites are mediators of OA-induced pulmonary edema in the isolated perfused rabbit lung.
authors.affiliation: Department of Physiology, Medical University of South Carolina, Charleston 29425.
authors.forename: S A
authors.initials: SA
authors.lastname: Katz
authors.forename: M
authors.initials: M
authors.lastname: Venkatachalam
authors.forename: R K
authors.initials: RK
authors.lastname: Crouch
authors.forename: J E
authors.initials: JE
authors.lastname: Heffner
authors.forename: P V
authors.initials: PV
authors.lastname: Halushka
authors.forename: W C
authors.initials: WC
authors.lastname: Wise
authors.forename: J A
authors.initials: JA
authors.lastname: Cook
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002374:Catalase / Q000494:pharmacology*; D005609:Free Radicals; D066298:In Vitro Techniques; D008297:Male; D019301:Oleic Acid; D009829:Oleic Acids / Q000009:adverse effects*; D010100:Oxygen / Q000378:metabolism; D011652:Pulmonary Circulation / Q000187:drug effects; D011654:Pulmonary Edema / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control*; D011817:Rabbits
chemical_list: D005609:Free Radicals; D009829:Oleic Acids; D019301:Oleic Acid; D002374:Catalase; D010100:Oxygen