[Contractile function and antioxidative system of the myocardium of the intact rabbit during hyperbaric oxygenation].

Daily exposures of rabbits to the HBO (2 ata, 1 hr) enhanced activity of glutathione-peroxidase for all 28 days of exposure. Other parameters of the antioxidative defence and the contractile function remained unchanged. The 2.5-ata oxygenation sharply reduced the activity of antioxidative enzymes, the antioxidative activity of lipids, and the tissue resistance against the induced peroxide oxidation of lipids. The heart contractile function was obviously worsened. Sites of necrosis appeared in the myocardium tissue. Increase in oxygenation seems to lead to changes of adaptation of the antioxidative system, but the exhaustion of the latter's power reserves potentiates the toxic effect of hyperoxia.