Comparison of lipid peroxidation parameters in the heart,liver, and brain of rats with different degrees of resistance to hypoxia

The relationship between the intensity of lipid peroxidation and the activity of the antioxidant system in the heart, liver, and brain is studied in male Wistar rats with low and high resistance to hypoxia tested by being “raised” to an altitude of 11.5 km and in intact outbred rats. It is found that in all groups of rats the content of lipid peroxidation products is highest in the liver, lower in the heart, and lowest in the brain. In all groups, the rate of the ascorbate-induced lipid peroxidation is highest in the brain, lower in the liver, and lowest in the heart. The activity of the antioxidant system is highest in the brain, lower in the liver, and lowest in the heart of low-resistance and outbred rats, while in high-resistance rats it is the same in all the organs. Thus, the difference in the parameters of lipid peroxidation and, particularly, of the antioxidant system in the studied organs is most pronounced in rats with a low resistance to hypoxia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 2, pp. 138–143, February, 1996 Presented by A. I. Archakov, Member of the Russian Academy of Medical Sciences     

Lipid peroxidation parameters in the internal organs of rats with different degrees of resistance to hypoxia

Lipid peroxidation and the antioxidant system of the heart, liver, and brain are studied in adult male Wistar rats with high and low resistance to hypoxia tested by “raising” to an altitude of 11.5 km and in intact outbred rats. These parameters are found to be the same in the brain of low- and high-resistance rats, while the brain content of lipid peroxidation products is higher in both groups of Wistar rats compared with outbred rats. The heart and liver parameters are coupled to the resistance to hypoxia. Antioxidant activity prevails over lipid peroxidation in the hearts and livers of high-resistance rats, confirming that oxidation plays a major role in the damaging and lethal effects of acute hypoxia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 1, pp 26–29, January, 1996 Presented by A. I. Archakov, Member of the Russian Academy of Medical Sciences     

Effect of fensuccinal on experimental insulin resistance

The effects of new antioxidant fensuccinal on dexamethasone-induced insulin resistance in rats were studied. Oral administration of fensuccinal in a dose of 25 mg/kg for 2 weeks prevented basal hyperinsulinemia and insulin insensitivity of peripheral tissues. Fensuccinal also attenuated oxidative stress by decreasing the concentrations of primary and secondary lipid peroxidation products in liver homogenates. The ability of fensuccinal to prevent dexamethasone-induced insulin resistance is probably due to its antioxidant properties. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 7, pp. 42–44, July, 2000     

Individual resistance of the organism and nerve cell to hypoxia

The correlation between the pattern of a neuron's reaction to acute hypoxia and individual resistance to oxygen deficit is studied on ratsin vivo as well as on surviving slices of their cerebellumin vitro. According to the survival time in a pressure chamber simulating an altitude of 11 km all the rats were divided into groups of high resistance, medium resistance, and low resistance to hypoxia. Survival time was 4.2 times longer in the high resistance group than in the low resistance group. In the cerebellar slices of high resistance animals 61.5% high-resistance neurons and 38.5% low-resistance neurons were recorded. On the other hand, in the high resistance animals the percentage of high-resistance neurons and low-resistance neurons was 31.2 and 68.8, respectively. The period of hypoxia development was 4.32 times longer in the high-resistance neurons as compared to low-resistance neurons. It is speculated that individual differences in the resistance to O₂ deficit are of a hereditary nature and manifest themselves not only on the level of the whole organism, but also in the individual nerve cell. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 11, pp. 454–457, November, 1994     

Antihypoxic effects of derivative on the EEG power spectra in rats with different susceptibility to oxygen deficiency

The succinate-containing hydroxypyridine derivative yancarb increases both the altitude tolerated by rats and their survival time at a high altitude, particularly in rats with low resistance to hypobaric hypoxia; it also prevents both phasic changes in the EEG characteristic of hypobaric hypoxia and hemispheric asymmetry and paroxysmal activity in the brain of highly resistant rats in the 5000–10,000 m range and in rats with low resistance in the 5000–11,000 m range. Antihypoxic effects of this substance are more pronounced in low-resistance rats and in the left hemisphere of both high- and low-resistant animals; in altitude range of 10,000–13,000 m these effects are weaker or absent. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 7, pp. 57–62, July, 1997     

Effect of fensuccinal on experimental insulin resistance

The effects of new antioxidant fensuccinal on dexamethasone-induced insulin resistance in rats were studied. Oral administration of fensuccinal in a dose of 25 mg/kg for 2 weeks prevented basal hyperinsulinemia and insulin insensitivity of peripheral tissues. Fensuccinal also attenuated oxidative stress by decreasing the concentrations of primary and secondary lipid peroxidation products in liver homogenates. The ability of fensuccinal to prevent dexamethasone-induced insulin resistance is probably due to its antioxidant properties. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 7, pp. 42–44, July, 2000     

Effect of acute hypoxia on resistance to hypoxia in rats

The resistance of rats to hypoxia was measured by survival time after exposure to high-altitude (11.5 km) hypoxia. The first exposure to acute hypoxia caused phasic changes in the survival time: short-term in high-resistant rats (about 24 h) and long-term in moderate- and lowresistant rats (38–39 days) starting from 1 h and 6–7 days after the first exposure, respectively. Adaptive reactions were more pronounced in low- and moderate-resistant rats, while disadaptation was typical of high-resistant animals. In all rats, the adaptive effect dominated until days 22–23. Throughout the testing, the initial type of resistance was retained in 79% of high-resistant rats, in 41% of low-resistant and in 33% of moderate-resistant rats, i. e., the initially homogenous groups formed after the first exposure in accordance with the type of resistance became mixed, which reduced the intergroup differences. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 6, pp. 625–628, June, 1999     

Role of glycolysis in the maintenance of the energy-synthesizing function of hepatocytes from rats adapted and nonadapted to hypoxia at different oxygen concentrations

It is demonstrated that the lactate-Po₂ dependence is the same in hepatocytes of rats with high and low resistance to hypoxia and does not correlate with phasic changes in the ATP concentration in the 890–50 μM O₂ region. Strong activation of lactate formation against the background of ATP decrease indicates that glycolysis is not the major mechanism determining the steady-state ATP level in the cell and affecting the ATP-Po₂ relationship in a wide range of oxygen concentrations. The intensity of glycolysis in hepatocytes of rats with high resistance to hypoxia is markedly increased after periodic adaptation to hypoxia but remains practically unchanged in the hepatocytes of low-resistance rats. This indicates that fundamentally different compensatory mechanisms are involved in this process in the liver of high- and low-resistance rats. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 28–32, January, 1995     

Adaptation to altitude hypoxia limits lipid peroxidation during inflammation and stress

Preadaptation of rats to altitude hypoxia results in reduced activation of lipid peroxidation during subsequent stress, inflammation, or both, as compared to hypoxiaunadapted animals, with the result that secondary changes in organs and tissues of adapted rats are much less pronounced and conditions are created for alleviating the acute inflammation and the stress reaction. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 6, pp. 590–593, June, 1995 Presented by E. D. Gol'dberg, Member of the Russian Academy of Medical Sciences     

Changes in the serum antioxidant system and lipid peroxidation under the influence of asbestos

The iron content, the state of the serum antioxidant system, and their relationship with the changes in lipid peroxidation in rat liver and lungs at the early stages of chrysotile-asbestos action, and the effect of the naturally occurring flavonoid rutin are studied. Intensification of lipid peroxidation in the liver and lungs and an increase in the oxyproline content, which correlates with the rise in serum antioxidant activity, are observed four weeks after a single intratracheal administration of 50 mg asbestos. The total serum iron content remains unchanged. Rutin has a pronounced anti-asbestos effect, inhibits the early stages of fibrosis, and facilitates normalization of the antioxidant system imbalance induced by asbestos. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 8 pp. 145–147, August, 1994     

Lipid peroxidation in the brain of rats differing in resistance to emotional stress

It is found for each of the rat brain regions studied (cerebral cortex, subjacent white substance, and brainstem) that both the initial levels of 2-thiobarbituric acid-reactive products and the rates of their increment are highest in rats resistant to emotional stress and lowest in stress-prone rats, and that the rates at which lipid peroxidation products accumulate are highest in the brainstem and lowest in the white substance. A correlation is presumed to exist between individual resistance to cerebral ischemia and the rate of lipid peroxidation in particular brain regions of healthy rats. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, № 10, pp. 384–387, October, 1994     

Sex-related differences in the degree of lipid peroxidation activation and resistance to cardiovascular damage induced by stress in rats

It is shown that during stress a rapid twofold increase of erythrocyte acid resistance in rats of both sexes was followed by a 1.5-fold decrease toward the 60th min in males and the 120th min in females. In males, in contrast to females, the level of malonic dialdehyde was raised not only during stress, but also 1 and 24 hours after its completion. Stress-induced dystrophic changes of cardiomyocytes were more marked in males. The area of myocardial damage in females was almost twice as small as in males. It is assumed that the better resistance of females to stress-induced cardiovascular damage may be due to increased efficacy of antioxidant mechanisms inhibiting lipid peroxidation. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, No 4, pp. 354–357, April, 1995 Presented by K. V. Sudakov, Member of the Russian Academy of Medical Sciences     

The use of a nonopiate leu-enkephalin analog and of hydra peptide morphogen for the correction of proliferation disturbances in tracheal epithelium and of LPO processes in lungs of newborn rats exposed to prenatal hypoxia

Newborn rats were born of females exposed to high-altitude hypoxia. Pregnant females were injected i.p. either nonopiate leu-enkephalin analog or hydra peptide morphogen 10 μg/kg 30 min prior to being placed in a pressure chamber. Prenatal hypoxia causes the inhibition of the proliferative processes in tracheal epithelium and activation of lipid peroxidation (LPO) in lungs of newborn rats. The administration of nonopiate leu-enkephalin analog prevents the development of posthypoxic alterations in newborn rats. The administration of hydra peptide morphogen inhibits the proliferation of tracheal epithelium and lowers the activity of the antioxidant defense of the lungs in newborn rats. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 5, pp. 535–537, May, 1994 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences     

Correlation between the parameters of free-radical lipid peroxidation and antioxidant system in children living in the north

A comparative study of the parameters of free-radical lipid peroxidation and antioxidant system was performed in children living in the North for various time periods. Intense lipid peroxidation was shown to be the key factor in the pathogeneses of several diseases caused by disturbances in the cellular membrane. Decreased resistance of red blood cells to peroxidative hemolysis is a phenomenon characterizing the adaptation-violating processes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 9, pp. 342–344, September, 1998     

Adaptation to periodic hypoxia and a diet supplemented with polyunsaturated class ω-3 fatty acids enhance the resistance of Ca2+ transport in the myocardial sarcoplasmic reticulum to free-radical oxidation

The relationship between the level of accumulation of lipid peroxidation products and the status of the Ca²⁺-transporting system in the sarcoplasmic reticulum of the rat myocardium is studied against the background of two cardioprotective factors, namely adaptation to periodic hypoxia and a diet enriched in polyunsaturated fatty acids of the ω-3 class. It is shown that the diet leads to an increase of level of lipid peroxidation products by 1.8 times in the heart and by 19 times in the liver, whereas a adaptation has no effect on the level of lipid peroxidation products in either of these organs. At the same time, the combined action of both factors considerably enhances the resistance of the myocardial Ca²⁺-transporting system to free radical-induced oxidation. Inin vitro experiments it is shown that adaptation to periodic hypoxia results in a more than twofold deceleration of Ca²⁺ transport inhibition during the oxidation induction by the Fe²⁺/ascorbate system; the diet causes a 3.5-fold deceleration of such inhibition. The results show that the accumulation of a high level of lipid peroxidation products is not always followed by damage to the Ca²⁺-transporting system in the myocardial sarcoplasmic reticulum. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 7, pp. 42–45, July, 1995 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Effect of ozone on lipid peroxidation in rat hearts isolated against the background of clinical death

Clinical death of outbred albino rats ensues after rapid blood loss due to a cut in the coronary coronary artery. Five minutes later, the isolated heart is perfused with ozonized Krebs-Henseleit solution. The activity of the antioxidant system in the heart is increased compared with that during routine oxygenation. The intensity of lipid peroxidation assessed by the intensity of chemiluminescence and the amount of lipid peroxidation products is significantly decreased during ozonization. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, № 2, pp. 161–163, February, 1996 Presented by B. A. Korolev, Member of the Russian Academy of Medical sciences     

Lipid peroxidation and antioxidant enzymes in the brain of rats exposed to acute emotional stress: Effect of interleukin-1β

Acute emotional stress is shown to raise the level of malonic dialdehyde in the hypothalamus of August rats. After intraventricular administration of interleukin-1β, the malonic dialdehyde level and the activity of antioxidant enzymes tended to rise selectively in the hypothalamus (but not in the sensorimotor cortex) of August, Wistar, and WAG rats. In the presence of this interleukin, acute emotional stress did not cause increases in lipid peroxidation products in the hypothalamus of August rats. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 9, pp. 244–247, September, 1995     

Protective effects of trimetazidine in acute hypoxia

Trimetazidine improves resistance to acute hypobaric hypoxia. Intraperitoneal injection of this preparation in an optimal protective dose (25 mg/kg) to rats prevents serious disturbances of energy metabolism and activation of lipid peroxidation in the brain, heart, and liver. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 4, pp. 410–412, April, 1998     

Experimental study of the possibility of metabolic correction of maternal, fetal, and newborn hypoxia in rats using a new amino acid composition MR-33

The status of pregnant rats, their fetuses, and progeny exposed to oxygen insufficiency are compares. By the end of pregnancy the resistance to hypoxia markedly decreases. Newborn rats during nursing are highly resistant to hypoxia. When nursing period is over, the resistance to hypoxia drops, but later is gradually restored. MR-33 preparation produces a pronounced antihypoxic effect. Administration of the drug to pregnant rats not only appreciably improves their resistance to oxygen insufficiency, but also promotes adaptation and compensatory mechanisms in the progeny, thus helping the progeny to better tolerate hypoxia, particularly when its probability is particularly high. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 10, pp. 451–454, October, 1997     

Criteria of individual and population-wide resistance to acute hypoxia

It is shown that the geometric mean of survival time and the deviation of σ from τ are measures of a population's resistance to acute hypoxia; that a measure of the individual resistance of an animal to such hypoxia is Student's parameter for that animal; that the distribution of Student's parameter in a population is a lognormal distribution under any conditions; and that the number of animals with low resistance is always equal to the number of highly resistant animals. The procedure described makes it possible to limit the number of animals used in an experiment by recording with the requisite accuracy the proposed measures of resistance to acute hypoxia at the population and individual levels. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 9, pp. 239–241, September, 1995