ИСТИНА

Realization of adaptation to intermittent hypoxia connected with two kinds of signals: hypoxia per se and induction of reactive oxygen species (ROS) in reoxygenation period. Hypoxia activates specific mechanisms of protection and compensation of oxygen insufficiency. Reactive oxygen species activate non-specific mechanisms of body protection and resistance. Last pathway play role in beneficial effects of adaptation to many environmental factors like physical load, stress, and so on, taken in limit intensity. We proposed a mode for increase the non-specific resistance which is developing in consequence of adaptation to hypoxia. We used reoxygenation not to normoxic level but to slight hyperoxia (30% O2). In case of intermittent adaptation to hypoxia-hyperoxia (5 min each, 1 h a day, daily), we have got more fast and deep development of antistress and antihypoxic protection in compare with adaptation to hypoxia-normoxia (same time protocol) in rats. Prenosological intoxication with a mixture of benzene and bichromate reduces physical endurance, increase stress behavior, activate free radical oxidation in liver, disturbs the activity of antioxidant enzymes, elevates HIF-1α and HOх-1 levels. Both adaptation to hypoxia-hyperoxia and adaptation to hypoxia-normoxia prevent following toxicant-induced reduction of physical endurance, growth slowing, decrease of HIF-1α and HOх-1 concentrations. But only adaptation to hypoxia-hyperoxia increase physical endurance, induces antioxidant system, decrease free radical oxidation and prevents stress behavior. Protection effect of adaptation to hypoxia-hyperoxia developed earlier than adaptation to hypoxia-normoxia.