[abstract] USE OF NITROXIDE RADICALS IN PULMONARY OXYGEN TOXICITY.

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[abstract] USE OF NITROXIDE RADICALS IN PULMONARY OXYGEN TOXICITY.

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Title: [abstract] USE OF NITROXIDE RADICALS IN PULMONARY OXYGEN TOXICITY.
Author: Bitterman, N; Adir, Y; Sova, Y; Resnick, M; Zissman, D; Brod, V; Bitterman, H
Abstract: BACKGROUND: Nitroxides are stable, cell permeable radicals, capable of neutralizing reactive oxygen species, that exert beneficial effects in oxidative damage. We studied the effects of two stable nitroxide radicals, which differ in their solubility properties, in pulmonary oxygen toxicity in rats. METHODS: 55 male rats were exposed in a sealed chamber to oxygen (97±2%) or air at 0.1MPa for 60 hrs. Seven groups were studied: 1-4) exposure to oxygen and treatment with Tempo (2,2,6,6, tetramethylpiperidine) (20mg/kg) or 4-hydroxy Tempo (Tempol) (80mg/kg) injected 1.P. every 12 or 24 hrs; 5-6) exposure to oxygen and injection of the vehicle every 12 or 24 hrs; 7) control group exposed to air. Toxicity was assessed by lung wet to dry weight (W/D) ratio (an indicator of lung water content), pleural fluid, and graded quantified histological detection of hemorrhagic edema, capillaritis, venulitis, perivascular and peribronchial infiltration. RESULTS: Exposure to oxygen resulted in significant increases in lung W/D ratio and pleural fluid as well as a distinct lung damage characterized by hemorrhagic edema, capillaritis, venulitis, perivascular and peribronchial infiltration. Pre-treatment with Tempo given every 24 hrs resulted in significant decreases (P<0.05) in W/D ratio (5.34±0.25 vs. 6.46±0.39), hemorrhagic edema (grade 1.7±0.1 vs. 2.8±0.2), capillaritis (1.6±0.1 vs. 2.7±0.2), venulitis (0.8±0.3 vs. 1.8±0.2) and perivascular infiltration (0.2±0.1 vs. 1.3±0.3). In contrast, Tempo given every 12 hr exerted no protective effect and enhanced the accumulation of pleural fluid (p<0.05). No significant difference in any of the variables was found after treatment with Tempol. CONCLUSIONS: This study supports the role of reactive oxygen species in pulmonary oxygen toxicity. The results demonstrate a protective effect of the lipophylic stable nitroxide radical Tempo and no significant effect of its hydrophilic derivative. The actions of high dose Tempo may represent a "dose window" beyond which an antioxidant may exert a pro-oxidant activity.
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org)
URI: http://archive.rubicon-foundation.org/6685
Date: 2000

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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