[The effect of altered oxygen partial pressure on the resisitance to hypoxia and expression of oxygen-sensitive genes in Drosophila melanogaster].

As a result of resistance test to hypoxia of Drosophilas melanogaster of Oregon strain, we identified a high resistance (Group II) and low resistance (Group III) subpopulations of flies. Flies from groups II and III were incubated in a constant normobaric hypoxia (Po2=62-64 mm Hg) for 10 generations. A highly resistant group (Group IV) were exposed to a shortterm anoxia (Po,=1,5 mm Hg, 5 min) every generation. Larvae from Groups II, III, and IV demonstrated significantly elevated levels of Sir and CG 14740 expression. Larvae from Group II had a significantly higher expression of CG 14740 compared to group III. The restitution time after exposure to anoxia was significantly reduced in Group II (on 31% of the control values) Our results suggest that long-term adaptation to low oxygen partial pressure of highly resistant Drosophila significantly reduces the time of restitution and increases the expression of Sir2 and CG14740 genes.

[The influence of low partial oxygen pressure on the biolodical process of mesenchymal stromal cells].

The influence of low partial oxygen pressure (Po2) on the amino acid composition in culture medium of human mesenchymal stromal cell (MSC) lines 4BL has been studied. At 23 mm Hg (3% oxygen), a significant decrease (by 31%) in the concentration of proline and hydroxyproline was registered. Under these conditions, the concentration of serine and aspartic acid decreased by 45% compared to the control. Maximum consumption of free amino acids from the culture medium required for the synthesis of collagen (proline and hydroxyproline by 42%, serine and aspartic acid by 62%) was observed at a gas-phase Po2 of 38 mm Hg (5% O2). At Po2 76 mm Hg (10% O2), a lack of amino acids proline and hydroxyproline was only 21%, while that of glutamine and alanine amounted 12% compared to the control. This intensity ratio of consumption of amino acids may indicate that the maximum of MSC vital functions occurs at Po2 38 mm Hg.

[The effect of melatonin on bone tissue metabolism].

In a review of the current literature for the 2000-2013 period, the data of the effect of melatonin on organic and inorganic matrix of bone tissue have been presented. These results suggest that melatonin is an important mediator in the formation of bone tissue. It can prevent the premature destruction of bone and promote its recovery through mechanisms of melatonin-related receptors and receptors of independent action.

[Determination of age-related liver stiffness changes in rats according to the ultrasonic shear wave elastography].

We examined by ultrasound shear wave elastography (SWE) changes of liver stiffness (LS) in three groups rats of different ages. LS measurement by SWE was performed on "Ultima PA" equipment ("Radmir", Kharkov, Ukraine) with a 10-5 MHz linear transducer. To assess the functional state of the liver at the same time we studied age-related biochemical and morphological differences in the liver. A valid LS determination (success rate of at least 60%) was observed in 96.6% animals of different age groups. We observed statistically significant increasing of LS between 3-month and 20-month rats (p = 0.010), but its value in each group do not exceed normal or reference range. In article discussed possible connection between age-related changes of LS and state of connective tissue elements, functional activity, hydration, etc. It is concluded that shear wave elastography may be a new objective biophysical method for obtaining information about the state of the liver stiffness of the liver tissue.

[Dosed normobaric hypoxia as a non-medication approach of stimulation of physiological regeneration of liver parenchyma].

The investigation was devoted to studying the effects of different modes of dosed normobaric hypoxia on the changes in morphometric indexes of functional activity and physiological regeneration of liver parenchyma in young rats. It was shown, that in rats exposed to hypoxic gas mixture (10% O2), the amount of karyonucleus and binuclear hepatocytes, nucleocytoplasmic and nucleolar-nuclear correlation increased. The changes in these indexes appeared to be more intensive when dosed normobaric intermittent hypoxia was administered with alternation of deoxygenation and reoxygenation periods. We believe that dosed normobaric hypoxia increases the functional activity and physiological regeneration of liver parenchyma.

[Normobaric hyperoxia affects osteogenesis in rats].

We studied the influence of normobaric hyperoxia on bone metabolism in 3- and 12-month-old male Wistar rats. Maintaining young rats (3 months) during the 14-hour daily sessions under normobaric hyperoxia (90% O2) was accompanied by a significant decrease in the concentration of C-terminal propeptides of collagen type I (by 36%), the acid phosphatase activity (by 32%), an increased activity of alkaline phosphatase (by 64%), an increased concentration of pyridinoline (by 37%) and 3-CrossLaps (by 8%), glycosaminoglycans (by 72%) in the blood serum. We believe that normobaric hyperoxia (90%) is accompanied by the disturbance of collagen synthesis. In adult rats under the same conditions for 14 sessions, the concentration ofglycosaminoglicans significantly increased by 60% relative to the control values. After 28 sessions of breathing the normobaric gas mixture containing 90% O 2 this parameter increased by 195%. Breathing normobaric gas mixture containing both 40% and 90% of O2 for 14 and 28 days decreased the acid phosphatase activity and the tartrat-resistant acid phosphatase activity by 18-25%. We believe that in adult animals 90% hyperoxia does not affect the activity of osteoblasts, but breaks the link between glycosaminoglicans and collagen fibrils, decreases the activity oflysosomal enzymes which are produced by osteoclasts and which can inhibit osteogenesis.

[Effect of normobaric hyperoxia on the markers of bone tissue metabolism].

We studied the influencing of normobaric hyperoxia one hour daily during 14 and 28 days on the bone metabolism for 3- and 12-monthly Wistar male-rats (n =80). It was shown, that breathed normobaric gas mixture with 90% O2 during 14 days significant reducing of C-terminal propeptides of type I collagen levels for 36%, an increasing piridinolin levels for 37% and concentration of C-terminal telopeptides of type I collagen for 8% in the blood serum. We found reliable decreasing the concentration ofpiridinolin levels for 27% in adult rats in the same conditions. The C-terminal propeptides of type I collagen levels did not change in any of the groups' research. We believe that 14 days normobaric hyperoxia (90%) in young animals accompanied by violation of collagen synthesis. The adult rats were more stable and had no changes after influence the two hyperoxia levels.

[Correction of the bone tissue changes in the deficit of mechanical loading].

In a review the analysis of modern medical technologies of correction of the state of bone tissue is presented at situational hipokinezii, weightlessness or deficit of loading.

[The effect of preadaptation on the acute hypobaric stress and physiological bone tissue regeneration].

In experiments on rats we investigated the resistance to the barochamber testing (12000 u.s.l velositi 80 m/s) before and after training for 14 and 28 days in the normobaric gas mixture (N2 + O2, Po, = 100 +/- 10 mm of Hg). It was shown that after preadaptation the resistance to acute hypobaric hypoxia increased 1.7-1.8 times. Alimentary deprivation (40%) does not essentially affect the resistance to hypoxia. Biochemical markers show that normobaric low-dosed hypoxic preadaptation (14 days) activates the physiological regeneration process, promote the increase in concentrations of leptin, parathyreoid and growth hormones. Alimentary deprivation decreased an alkaline phosphatase activity and concentration of growth hormone. We suggest that normobaric hypoxic preadaptation but not alimentary limitation has definite positive influence on the bone tissue state.

[The effect of dosed normobaric hypoxia on physiologic regeneration of the liver parenchima in young and old rats].

We studied the effect of dosed normobaric hypoxia during 28 days on functional state and physiological regeneration of liver parenchyma. After completion of experiments in 3 and 9-month old rats we observed an increase in the amount of hepatocytes per unit of tissue area, with hypertrophied nucleus and decreased cytoplasmic area. IGF-I gene expression in 9-month old animals was increased. Thus, our study suggests that normobaric hypoxia stimulates physiological regeneration of liver parenchyma in young and adult rats.

[The bone tissue remodeling in young and adult rats in conditions of alimentary deprivation].

We studied the influencing of designed during 28 days alimentary deprivation on the bone tissue physiological remodeling processes for 3- and 9-monthly Wistar rats-males (n=32). 4 groups of animals are probed: I, III - control, II, IV is the mode of calorie limitation (40% in relation to a valuable ration for every age group). It is shown, that alimentary deprivation increase the concentration of melatonin, glycosaminoglycans in blood serum and activity ofalkaline phosphatase in serum and bone tissue in 1,4 and 1,2 time accordingly at for young rats. For adult rats the reliable decline of activity of alkaline phosphatase is exposed in the blood serum after alimentary deprivation. Expression of gene ofinsulinlike growth factor-I for animals of both probed groups did not change practically. We conclude, that alimentary deprivation change the biochemical markers of bone tissue physiological remodeling for young animals, while the changes of physiological regeneration rates were insignificant for adult animals.

[Alimentary and oxygen deprivation as the modulator of the bone tissue physiological remodelling rate in young rats].

Influencing of 28-days alimentary deprivation and intermittent hypoxia to 3 months Wistar male rats (n = 30) bone tissue physiological remodelling is studied. We investigated 3 groups of animals, I group was control, II--food limitation mode (-40% in relation to the normal ration) and III--animals, which breathed hypoxic gas mixture with 13% O2 in nitrogen (HGM) during 4 hours in the intermittent mode (10 min of deoxygenation and 10 min of reoxygenation). It is showed significant increasing of melatonin and glicozaminoglikans levels in the rats II and III gr. serum. Activity of alkaline phosphatase in the bone tissue of III gr. rats increased and in the bone tissue and serum of II gr. rats for 1.2 and 1.4 time accordingly. We registered significant increasing of serum acid phosphatase activity in animals, which have breathed hypoxic gas mixture. The IGF-I gene expression level did not change practically in both experimental groups. We conclude, that alimentary deprivation and intermittent hypoxia have positive effects on the physiological remodelling of bone tissue.

[Effect of alimentary deprivation on physiological regeneration of the liver parenchyma in young and mature rats].

It was studied the effects of alimentary deprivation during 28 days on functional state and physiological regeneration of liver. In 3 and 9-month rats it was shown an increase in the amount of hepatocytes per unit of area of tissue, their nucleis were hypertrophied, the area of cytoplasm was decreased, the number of binucleitic hepatocytes in 9-month animals was increased. Thus, our study suggests that a short-term 40% food limitation stimulates physiological regeneration of liver parenchyma.

[Effect of dosed normobaric hypoxia on the bone tissue physiological regeneration].

We investigated the effect of dosed normobaric hypoxic gas mixtures with reduced oxygen partial pressure in the different modes on stimulation of the physiological bone tissue regeneration process in adult rats. It is shown that nitrogen and oxygen gas mixture (Po2 = 76 mm Hg) application in the modes 10 min deoxygenation--10 min reoxygenation during 4 hours daily or during 1 hour continuously is the optimum for an increase of biochemical markers of physiological regeneration of bone tissue.

[Impedance testing of compact bone tissue in hypokinetic rats].

The bioelectrical impedance method was used for determination of compact bone status in white rats after 28th days of strong hypokinesia. It was shown that the lowering of mechanical loading leads to disturbances in dielectric properties and changes in electrical impedance parameters. These disturbances had different direction and manifestation. It was distinguished the two typical variants of bone dielectric properties changes. The first variant was more characteristic for early stages of hypokinetic osteodestruction, the second variant was more characteristic for the fully development hypokinetic disturbances. It was determine a correlation between the changes in electrical impedance parameters and mane components of bone matrix. The results of this study show that hyperhydratation of bone tissue play important role in hypokinetic changes of bone dielectric properties. Electroimpedance method may be used for early diagnostic of bone state in clinic and experiments.

[The model of hypokinesia in rats and preventing its negative effects].

The special container for modeling of long-term hypokinesia state in rats was developed. Such construction allows us to examine simultaneously hypokinesia and its negative influence correction by gas mixture regulated with different oxygen partial pressure.

[The modeling of experimental osteopenia in rats and development of prophylaxis technology]. / Modeliuvannia eksperymental'noï osteopeniï ta rozrobka tekhnolohiï ïï profilaktyky u shchuriv.

An appliance for hind limb unloading in rats and the technology for preventing of inactivity osteopenia have been developed.

[Oxygen deprivation as the initiator of osteogenesis in hypokinesia]. / Kysneva depryvatsiia iak initsiator osteohenezu pry hipokineziï.

The hypokinesia initiated on the distrophic changes in the rats' femur bones was studied. The interrupted normobaric hypoxia destructive inhibited possibility in the bone tissue was also investigated. It was shown that inspiration the gaz mixture (nitrogen and oxygen (Po2 = 100-110 mm Hg) normalizes the biochemical markers, greatly minimizes the loss of the secondary spongioza due to the decrease of osteoclastic resorption activity; normalizes the compact bone perepheric layers. The decreased osteoblasts activity in comparison with the control in the metaphysis and the smaller length growth indicate non-complete hypokinesia influence compensation after the oxygen deprivation.

[The effect of measured hypoxia on the development of situational osteopenia]. / Vplyv dozovanoï hipoksiï na rozvytok sytuatsiinoï osteopeniï.

The influence of gas mixture with low PO2 (90-110 mm Hg) on calcium-phosphorus metabolism and biomechanical properties of femur bones at rats, who were kept under condition of hind-limb unloading during 28-days, has been studied. Loss of calcium and phosphorus during a day was less in rats, who was received gas mixture with lower PO2, than rats who was kept in condition of hind-limb unloading only. Hypoxic gas mixture stabilized mechanical properties of bones tissue in femoral bone of rats. Gas mixture with lower pressure of oxygen retard development of osteopenia and may be used with other corrective methods for situation osteopenia prevention.