• Gerald S Supinski and Leigh A Callahan.
• Pulmonary and Critical Care Division, Department of Medicine, Medical College of Georgia, Augusta, GA 30912, USA. gsupinski@mail.mcg.edu
• Am. J. Respir. Crit. Care Med. 2006 Jun 1;173(11):1240-7.

RationaleSepsis produces significant mitochondrial and contractile dysfunction in the heart, but the role of superoxide-derived free radicals in the genesis of these abnormalities is not completely understood.ObjectivesThe study was designed to test the hypothesis that superoxide scavenger administration prevents endotoxin-induced cardiac mitochondrial and contractile dysfunction.MethodsFour groups of rats were studied, and animals were injected with either saline, endotoxin, endotoxin plus polyethylene glycol-adsorbed-superoxide dismutase (PEG-SOD; a free-radical scavenger), or PEG-SOD alone. Animals were killed 48 h after injections. We then measured cardiac mitochondrial generation of reactive oxygen species (ROS), formation of free-radical reaction products (protein carbonyls, lipid aldehydes, nitrotyrosine), mitochondrial function, and cardiac contractile function.Measurements And Main ResultsEndotoxin elicited increases in cardiac mitochondrial ROS formation (p < 0.001), increases in cardiac levels of free-radical reaction products, reductions in mitochondrial ATP generation (p < 0.001), and decrements in cardiac pressure-generating capacity (p < 0.01). Administration of PEG-SOD blocked formation of free-radical reaction products, prevented mitochondrial dysfunction, and preserved cardiac contractility. For example, mitochondrial ATP generation was 923 +/- 50, 392 +/- 32, 753 +/- 25, and 763 +/- 36 nmol/min/mg, respectively, for control, endotoxin, endotoxin + PEG-SOD, and PEG-SOD groups (p < 0.001). In addition, cardiac systolic pressure generation at a diastolic pressure of 15 mm Hg averaged 110 +/- 11, 66 +/- 7, 129 +/- 10 and 124 +/- 5 mm Hg, respectively, for control, endotoxin, endotoxin + PEG-SOD, and PEG-SOD groups (p < 0.01).ConclusionThese data indicate that superoxide-derived oxidants play a critical role in the development of cardiac mitochondrial and contractile dysfunction in endotoxin-induced sepsis.

37 keywords...

hide…