Role of TNF-alpha-induced reactive oxygen species in endothelial dysfunction during reperfusion injury.
We hypothesized that neutralization of TNF-alpha at the time of reperfusion exerts a salubrious role on endothelial function and reduces the production of reactive oxygen species. We employed a mouse model of myocardial ischemia-reperfusion (I/R, 30 min/90 min) and administered TNF-alpha neutralizing antibodies at the time of reperfusion. I/R elevated TNF-alpha expression (mRNA and protein), whereas administration of anti-TNF-alpha before reperfusion attenuated TNF-alpha expression. We detected TNF-alpha expression in vascular smooth muscle cells, mast cells, and macrophages, but not in the endothelial cells. I/R induced endothelial dysfunction and superoxide production. Administration of anti-TNF-alpha at the onset of reperfusion partially restored nitric oxide-mediated coronary arteriolar dilation and reduced superoxide production. I/R increased the activity of NAD(P)H oxidase and of xanthine oxidase and enhanced the formation of nitrotyrosine residues in untreated mice compared with shams. Administration of anti-TNF-alpha before reperfusion blocked the increase in activity of these enzymes. Inhibition of xanthine oxidase (allopurinol) or NAD(P)H oxidase (apocynin) improved endothelium-dependent dilation and reduced superoxide production in isolated coronary arterioles following I/R. Interestingly, I/R enhanced superoxide generation and reduced endothelial function in neutropenic animals and in mice treated with a neutrophil NAD(P)H oxidase inhibitor, indicating that the effects of TNF-alpha are not through neutrophil activation. We conclude that myocardial ischemia initiates TNF-alpha expression, which induces vascular oxidative stress, independent of neutrophil activation, and leads to coronary endothelial dysfunction.
Gao
Xue
X
Department of Internal Medicine, Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO 65211, USA.
Zhang
Hanrui
H
Belmadani
Souad
S
Wu
Junxi
J
Xu
Xiangbin
X
Elford
Howard
H
Potter
Barry J
BJ
Zhang
Cuihua
C
D000818:Animals; D000906:Antibodies / Q000008:administration & dosage; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology; D005260:Female; D008297:Male; D051379:Mice; D008833:Microcirculation; D009131:Muscle, Smooth, Vascular / Q000378:metabolism / Q000503:physiopathology; D015428:Myocardial Reperfusion Injury / Q000276:immunology / Q000378:metabolism* / Q000503:physiopathology / Q000517:prevention & control; D019255:NADPH Oxidases / Q000378:metabolism; D009503:Neutropenia / Q000378:metabolism / Q000503:physiopathology; D009569:Nitric Oxide / Q000378:metabolism; D018384:Oxidative Stress; D009195:Peroxidase / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D014664:Vasodilation; D014969:Xanthine Oxidase / Q000378:metabolism
D000906:Antibodies; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; D009195:Peroxidase; D014969:Xanthine Oxidase; D019255:NADPH Oxidases