Effect of reactive oxygen metabolites on endothelial permeability: role of nitric oxide and iron.
OBJECTIVE
We evaluated the effects of the xanthine oxidase (XO)-derived reactive oxygen metabolites on the permeability of bovine pulmonary artery-endothelial monolayers and examined how iron and nitric oxide (NO) participate in these changes in permeability.


METHODS
Permeability was measured using a cell-column chromatographic method in which monolayers were exposed to combinations of agents.


RESULTS
Exposure of monolayers to a superoxide/peroxide generator, xanthine (X, 0.1 mM)/XO (25 mU/mL), increased solute permeability after 10 minutes, but the same dose of either X or XO alone did not. Exposure of monolayers to peroxide (0.1 mM) also increased permeability, but only after 70 minutes. This X/XO permeability was attenuated by either catalase, superoxide dismutase, methionine (1 mM), an oxy-radical scavenger, or desferrioxamine (0.1 mM), an iron chelator. Spermine NONOate (SNO), an NO donor, attenuated X/XO permeability at 0.1 mM, but this protection was not significant at 0.01 or 1 mM. Spermine NONOate (0.1 mM) did not alter the permeability produced by 0.1 mM peroxide. L-N5-(1-iminoethyl)-ornithine (10 microM), an NO synthase inhibitor, completely blocked peroxide-, and partially attenuated X/XO-mediated permeability. However, 3-morphosynodiomine (SIN-1, 1 mM) plus catalase (1,000 U/mL), a peroxynitrite generator, did not alter permeability.


CONCLUSIONS
Xanthine/Xanthine Oxidase permeability involves peroxide, superoxide, oxy-radicals, and iron. Endogenous NO may regulate peroxide-, but not superoxide-mediated permeability. The protective effects of exogenous NO on the X/XO permeability may represent interactions between superoxide, peroxide, and cell surface-bound iron.
Okayama
N
N
Department of Molecular and Cellular Physiology, Louisiana State University Medical Center, Shreveport 71130-3932, USA.
Grisham
M B
MB
Kevil
C G
CG
Eppihimer
L A
LA
Wink
D A
DA
Alexander
J S
JS
D000818:Animals; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology*; D002374:Catalase / Q000494:pharmacology; D002417:Cattle; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D007700:Kinetics; D009566:Nitrates / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009589:Nitrogen Oxides; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013096:Spermine / Q000031:analogs & derivatives / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism; D019820:Xanthine / Q000494:pharmacology; D014969:Xanthine Oxidase / Q000494:pharmacology
D004791:Enzyme Inhibitors; D009566:Nitrates; D020030:Nitric Oxide Donors; D009589:Nitrogen Oxides; D017382:Reactive Oxygen Species; D013481:Superoxides; C091861:spermine nitric oxide complex; D019820:Xanthine; C039642:peroxynitric acid; D013096:Spermine; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D007501:Iron; D002374:Catalase; D019001:Nitric Oxide Synthase; D013482:Superoxide Dismutase; D014969:Xanthine Oxidase