Nitric oxide-induced oxidant stress in endothelial cells: amelioration by ascorbic acid.
Nitric oxide has multiple beneficial effects in the blood vessel wall. However, high concentrations of nitric oxide in the presence of hydroperoxides have been shown to damage cultured cells. In this work, the effect of relatively high concentrations of nitric oxide alone on the function and antioxidant status of a human endothelial cell line (EA.hy926) was tested. Nitric oxide generated from 0.1 to 0.5mM spermine NONOate generated reactive species in the cells detected by triazole formation from diaminofluorescein and by oxidation of dihydrofluorescein. Intracellular ascorbic acid decreased this oxidant stress. Spermine NONOate also decreased intracellular ascorbate concentrations, although reduced glutathione was not affected unless cells had also been caused to reduce dehydroascorbic acid to ascorbate. Nitric oxide predictably inhibited both endothelial nitric oxide synthase and glyceraldehyde 3-phosphate dehydrogenase, and ascorbate partially prevented inhibition of the latter enzyme. These results suggest that relatively high concentrations of nitric oxide can cause oxidant stress in endothelial cells that is ameliorated by ascorbic acid.
Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-6303, USA. james.may@vanderbilt.edu
James M
JM
May
Zhi-Chao
ZC
Qu
D001205:Ascorbic Acid / Q000378:metabolism*; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism*; D009589:Nitrogen Oxides; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D013096:Spermine / Q000031:analogs & derivatives* / Q000494:pharmacology*
D009589:Nitrogen Oxides; C091861:spermine nitric oxide complex; D013096:Spermine; D009569:Nitric Oxide; D001205:Ascorbic Acid