Dual role of endogenous nitric oxide in tumor necrosis factor shock: induced NO tempers oxidative stress.
Tumor necrosis factor (TNF) is involved in pathologies like septic shock, inflammatory bowel disease and rheumatoid arthritis. TNF and lipopolysaccharide can incite lethal shock, in which cardiovascular collapse is centrally orchestrated by the vasodilating free radical nitric oxide (NO). However, NO synthase (NOS) inhibition causes increased morbidity and/or mortality, suggesting a dual role for NO. To investigate the potential protective role of NO during TNF shock, we treated mice with TNF with or without NOS inhibition. Experiments in endothelial- NOS- and inducible NOS-deficient mice identified inducible NOS as the source of protective NO. Distinctive TNF-induced lipid peroxidation, especially in liver and kidney, was aggravated by NOS inhibition. In addition, various antioxidant treatments and a phospholipase A2 (PLA2) inhibitor prevented sensitization by NOS inhibition. Together, these in vivo results indicate that induced NO not only causes hemodynamic collapse, but is also essential for curbing TNF-induced oxidative stress, which appears to hinge on PLA2-dependent mechanisms.
Molecular Pathophysiology and Experimental Therapy Unit, Department for Molecular Biomedical Research, Ghent University and Flanders Interuniversity Institute for Biotechnology (VIB), Ghent, Zwijnaarde, Belgium. Anje.Cauwels@dmbr.UGent.be
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Cauwels
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Bultinck
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Brouckaert
D000447:Aldehydes / Q000032:analysis; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002083:Butylated Hydroxyanisole / Q000494:pharmacology; D002374:Catalase / Q000494:pharmacology; D003497:Cyclic N-Oxides / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D007150:Immunohistochemistry; D007275:Injections, Intravenous; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism* / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress; D010741:Phospholipases A / Q000037:antagonists & inhibitors; D054467:Phospholipases A2; D017382:Reactive Oxygen Species / Q000378:metabolism; D012769:Shock / Q000209:etiology / Q000378:metabolism* / Q000401:mortality; D013113:Spin Labels; D013482:Superoxide Dismutase / Q000494:pharmacology; D015996:Survival Rate; D048069:Tumor Necrosis Factors / Q000494:pharmacology* / Q000633:toxicity
D000447:Aldehydes; D000975:Antioxidants; D003497:Cyclic N-Oxides; D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D013113:Spin Labels; D048069:Tumor Necrosis Factors; D002083:Butylated Hydroxyanisole; D009569:Nitric Oxide; D002374:Catalase; D019001:Nitric Oxide Synthase; D013482:Superoxide Dismutase; D010741:Phospholipases A; D054467:Phospholipases A2; C027576:4-hydroxy-2-nonenal; C001803:tempol; D019331:NG-Nitroarginine Methyl Ester