OMEGA-3 POLYUNSATURATED FATTY ACIDS NORMALIZE THE FUNCTION OF MITOCHONDRIA, ACTIVITY OF ENZYMES OF PROOXIDANT-ANTIOXIDANT SYSTEM AND THE EXPRESSION OF CYTOCHROME Р450 2Е1 AFTER ISOPROTERENOLINDUCED MYOCARDIAL INJURY.

We have studied the influence of dietary ω-3 polyunsaturated fatty acids (ω-3 PUFA) on the functioning of subsarcolemmal and interfibrillar mitochondrial fractions of rat myocardium, changes in expression of cytochrome P450 (CYP2E1) and the activity of enzymes of prooxidant-antioxidant system after isoproterenol-induced myocardial injury. It has been found that in vivo administration of ω-3 PUFA (Epadol 0.1 ml/100 gr of weight for 4 weeks) significantly reduced the swelling of subsarcolemmal and interfibrillar mitochondrial fractions by 65.52% 54.84% respectively, pointing for a decrease of damage of the mitochondrial function evoked by in vivo administration of isoproterenol. In vivo administration of ω-3 PUFAs prevents a decrease in the activity of antioxidant enzymes catalase and superoxide dismutase (2.65 and 7.1- fold, respectively) after isoproterenol-induced myocardial injury. We suggest that the development of oxidative stress after isoproterenol-induced myocardial injury can be caused by a significant increase in the expression of cytochrome P450 2E1 (73.3%), and administration of ω-3 PUFAs prevents such changes.

[Effect of quercetin on proteasome activity in the aorta and heart tissues of spontaneously hypertensive rats].

To determine the role of proteasome proteolysis in the pathogenesis of hypertension, we have studied the proteolytic activity of the proteasome in the aorta and heart tissues of rats with spontaneous hypertension (line SHR), and used quercetin, the drug that can inhibit the activity of this multicatalytic complex. In the aorta of SHR, the activities of the proteasome were not significantly different from that observed in Wistar rats. At the same time, in the heart tissues the trypsin-like (at 40%, P > 0.05), and chymotrypsin-like (by 1.7 times, P < 0.03) activities were significantly less in SHR. Significant morphological changes (fibrosis of the left ventricle was 4.7%, aorta intima width was increased and heart weight index was higher by 21.6% (3.7 +/- 0.6 mg/g) compared with Wistar rats (2.9 +/- 0,4 mg/g, P < 0.004) were observed in these animals functional disorders (reduced stroke volume by 3 times (P < 0.0001), ejection fraction by 2.5 times (P < 0.0001), increased end diastolic pressure by 6.5 times (P < 0.005), end systolic pressure by 15% (P < 0.004)) were revealed. Pharmacological drug "Qvercetin" effectively inhibited trypsin-like and chymotrypsin-like proteasome activities in the aorta (2.7-fold (P < 0.005) and 2-fold (P < 0.003), correspondingly) and trypsin-like, and peptidyl-glutamyl peptide-hydrolyzing-like activities (2.4-fold, P > 0.05 and 9.3-fold, P < 0.02, correspondingly) activities in the heart, leading to a significant improvement of morphological and functional parameters of the heart. Whereas the drug "Qvercetin" that is widely used in clinical practice (especially in therapy of acute myocardial infarction) it could be recommended for the use in prevention of cardiac remodeling with high level of blood pressure.

[The changes in the activity of tripeptidyl peptidase II in experimental atherosclerosis and hypertension].

The changes in the activity of intracellular proteolytic systems are important mechanisms in the damage of blood vessels walls and arterial hypertension. Tripeptidyl peptidase II (TPP II) is one of the giant intracellular protease that is still poorly known. It fulfils hydrolysis of peptides, coming from proteasomal proteolysis. Modeling of cholesterol atherosclerosis in rabbits (1% of cholesterol in diet for 2 month) results in the significant decrease of TPP II activity in aorta tissues. This diet in spontaneously hypertensive rats (SHR) leads to a decrease of TPP II activity in aorta tissues (on 50%, P < 0.05) but has no influence on the activity of TPP II in Wistar rats. Application of Quercetin prevents the inhibition of TPP II activity in aorta tissues of rabbits and SHR at experimental hypercholesterolemia. The data received show that changes in the activity of TPP II play an important role in pathogenesis of blood vessels wall in atherosclerosis and arterial hypertension.

[The influence of dietary omega-3 polyunsaturated fatty acids on functional parameters of myocardial mitochondria during isoproterenol-induced heart injury].

We have studied the functional parameters of mitochondria from hearts after isopreterenol-induced injury (two subcutaneous injections of isopreterenol at the dose 60 mg/kg/day). We investigated the influence of dietary omega-3 polyunsaturated fatty acids (omega-3 PUFAs) administered to rats (Epadol, 0.1 mg/100 gr of weight for 4 weeks) on these parameters. Isoproterenol-induced heart injury leads to a decreased parameters of respiration of isolated mitochondria in the presence of succinate. Administration of omega-3 PUFAs significantly restored the respiration rate of mitochondria: the state 3 respiration was increased by 70.12%, the state 4 by 39.87% and the respiratory control ratio by 45.19% compared to the corresponding parameters of experimental group. Also, it was shown the ability of omega-3 PUFAs to decrease mitochondria swelling (by 60%) in nominally free calcium solution. The results of the study indicate that omega-3 PUFAs improve the altered functions of the heart mitochondria evoked by isoproterenol-induced injury.

[Biochemical mechanisms of the cardioprotective effect of the K(ATP) channels opener flocalin (medicinal form) in ischemia-reperfusion of myocardium].

In experiments on the anaesthetized dogs with modeling of experimental ischemia (90 min) and reperfusion (180 min) of myocardium it was investigated changes of biochemical processes in arterial blood at intragastric introduction of medicinal form (tablets) of flocalin (the fluorine-containing opener of ATP-sensitive potassium channels) in a dose 2,2 mg/kg. The data analysis allowed to define a few possible mechanisms of cardioprotective action offlocalin, which prevented the opening of a mitochondrial permeability transition pore (MPTP) and inhibition of apoptosis induced by it. They consist, from one side, in activating of the constitutive de novo biosynthesis of nitric oxide by cNOS, from other side, in suppression of inducible nitric oxide de novo synthesis by iNOS in such way to prevent the formation of toxic peroxynitrite by co-operation of surplus nitric oxide with superoxide anion, thereby limits the generation of toxic active forms of nitrogen (*NO2) and oxygen (*OH). The first effect of flocalin takes place due to limitation the degradation of L-arginine by arginase which keeps substrat for cNOS, second--due to the inhibition of superoxide generation, in particular, by xanthine oxidase (marker uric acid), lipoxigenase (marker LTC4) and cyclooxygenase (marker TxB2). Because LTC4 have coronaroconstrictory, arrhythmogenic and chemoattractory properties in the conditions of myocardial ischemia, inhibition of its production both with superoxide generation (markers H2O2 and diene conjugates) may be the another mechanisms of flocalin's cardioprotection. Powerful antiischemic action of flocalin (marker nitrite anion) as the mechanisms of cardioprotection is possible as well as inhibition of ATP and GTP degradation (marker hypoxanthine+xanthine+inosine levels in the blood) and, possibly, stimulation ofhaem degradation by haem oxygenase (markers total bilirubin and Fe in the blood). Diminishing content of free arachidonic acid in arterial blood can testify inhibition of cellular membranes phospholipides degradation by phospholipase A2 as a result of flocalin cardioprotection.

[Influence of flocalin on development of apoptosis and necrosis at anoxia-reoxygenation of culture rats neonatal cardiomyocytes].

The influence of the new cardioprotector flocalin was investigated on the culture of rat's neonatal cardiomyocytes during anoxia-reoxygenation modelling. The mechanisms of apoptosis and necrosis were investigated under influence of ATP-sensitive potassium (K(ATP)) channels activation and in conditions of blocking of the L-type calcium (VGCCs) channels. Flocalin was added in the culture medium in the dose 5 and 20 microM at 2 minutes before anoxia (30 minutes) and following reoxygenation (60 minutes). These doses are near to: the first dose means the opening of K(ATP) channels and the second one means the IC50 block of VGCCs. It is discovered that in dose 5 microM of flocalin drew the change of correlation of living, necrotizing and apoptizing cells drew side-shifting living. The number of live cells was almost the same like in control (experiments without anoxia-reoxygenation modelling). The opening of K(ATP) channels decreases necrosis in two times and fully prevented development of apoptosis which was induced anoxia-reoxygenation modelling. Flocalin depressed the apoptosis of neonatal cardiomyocytes so that he was on to 36% less than in control group (without anoxia-reoxygenation). But in the high dose (20 microM) that provokes not only K(ATP) channels opening but also IC50 block of VGCCs cardioprotection was not detected after modelling of anoxia-reoxygenation. The last can be investigation both enough strong activating of the potassium channels and by investigation of both factors are opening of potassium and inhibition of VGCCs channels and, accordingly, substantial diminishing of level of introcellular Ca2+ and violation of metabolic processes yet to anoxia-reoxygenation. Thus, small doses of flocalin, that induce moderate opening of K(ATP) channels significantly decrease the number of necrotic and apoptotic cells in culture of rat neonatal cardiomyocytes induced by anoxia-reoxygenation.

[The influence of activation of the ATP-sensitive potassium channels by flocalin on the function of the cardiovascular system].

In experiments on the anaesthetized dogs the influence of a new fluorine-containing opener of ATP-sensitive potassium (K(ATP)) channels flocalin on the cardiohemodynamic of great animals in vivo was studied. Flocalin introduced intravenously in doses 0.01 - 1.5 mgs/kg. It is shown that it reduces in dose-dependent manner a system arterial pressure, perfusion pressure in coronary artery and general peripheral resistance of vessels with maximal effects on 56.8 +/- 2.7, 22.4 +/- 4.7 and 47.2% +/- 6.5% accordingly at most dose 1.5 mgs/kg. Flocalin causes development of cardiodepressive reactions in heart, that is exhibited in dose-dependent the decrease of pressure in the left ventricle, speed of growth (dP/dt(max)) and reduction (dP/dt(min)) in it's of pressure with maximal effects on 37.1 +/- 5.1, 51.2 +/- 9.4 and 55.6% +/- 6.9% accordingly at introduction of most dose of flocalin. Diminish of the cardiac out put and heart rate with a maximal effects on 23.1% +/-12.7% and 19.2% +/- 1.7% accordingly at a dose 1.0 mgs/kg was shown. It should be noted that considerable reduction of heart rate and general peripheral resistance of vessels takes place only at the large doses of flocalin - 1 and 1.5 mgs/kg. Thus, it is shown that activation of K(ATP) channels by flocalin causes the dose-dependent decrease of pressure in the system of circulation of blood and contraction activity of myocardium.

[New fluorine-containing openers of ATP-sensitive potassium channels flokalin and tioflokalin inhibit calcium-induced mitochondrial pore opening in rat hearts].

In experiments in vitro on the mitochondria isolated from the rat's heart we studied the effects of the openers of ATP-sensitive potassium channels (K(ATP)-channels), flocalin and tioflocalin, on the calcium-induced mitochondrial pore (MPTP) opening. Flocalin and tioflocalin caused moderate Ca(2+)-independent mitochondria swelling, which was prevented by a specific inhibitor of 5-hydroxydecanoate. This allowed to identify these compounds as mitochondrial K(ATP)-channels openers. We found that concentration-dependent inhibitory effects (10(-7) to 10(-4) M) of flocalin (with IC50 = 50 microM) and tioflocalin (with IC50 = 2,7 microM) on Ca(2+)-induced mitochondrial swelling (MPTP opening) in the heart characterized more powerful cardioprotective action of the latter. It was shown that the administration of these compounds in experiments in vivo decreased the sensitivity of the MPTP opening to Ca2+. Thus, under physiological conditions the activators K(ATP)-channels probably provide the membrane-stabilizing effects, thereby effectively increasing the organelles resistance to Ca2+, an inductor of MPTP. The results obtained allowed to characterize the role of the compound studied as cardioprotectors and regulators of the MPTP formation in the heart, indicated their anti-ischemic and anti-apoptotic effects that can be used in order to correct the mitochondrial dysfunction under pathological conditions of the cardiovascular system.

Genetic predisposition to essential hypertension in children: analysis of 17 single nucleotide polymorphisms.

Study of 17 single nucleotide polymorphisms has been performed to determine the factors of genetic predisposition to essential hypertension. Polymerase chain reaction (PCR) with subsequent analysis of restriction fragment length, allele specific PCR or real-time PCR was used for genotyping of 17 single nucleotide polymorphisms in 14 genes in 145 children with essential hypertension and 144 healthy persons with following complex multivariate statistical analysis. Two single nucleotide polymorphisms--MMP9 (C(-1562) --> T) and NOS3 (Glu298 --> Asp)--rs3918242 and rs1799983--were shown to represent the main independent effects with the highest predictive potential (77.1% as indicated by binary logistic regression and 74.6% testing accuracy shown by Multifactorial Dimensionality Reduction). MMP9 (C(-1562 --> T) and NOS3 (Glu298 --> Asp) potentially may be used to create predictive algorithm for determination of predisposition to arterial hypertension in children.

[T(-786) --> C-polymorphism of the endothelial nitric oxide synthase promoter gene (eNOS) and exercise performance in sport].

Given the significant impact of the T(-786) --> C-polymorphism of the eNOS gene in the process of adaptation to physical stress, we aimed to investigate the effect of this polymorphism on physical performance in sportsmen and establish the possibility of its use as a marker of predisposition to the sport. DNA of 516 people, of which 195 qualified athletes and 321 people who had no experience of regular exercise was investigated. The frequency of genotypes and alleles of the T(-786) --> C-polymorphism of the eNOS gene in groups of athletes of different sports, the distribution of genotypes and alleles among athletes and those who are not involved in sports were studied. T allele frequency in a group of athletes on 6.4% (r(chi)2 = 0.03) than in control group. The association of the T allele of the T(-786) --> C-polymorphism of the eNOS gene with a predisposition for speed and power was established. In the group of athletes in speed and power sports, the T-allele frequency was higher than that in the control group by 12% (r(chi)2 = 0.002) and than in group endurance sports by 10% (r(chi)2 = 0.004). We found that the T(-786) --> C-polymorphism of the eNOS gene influence the power and efficiency ofthe functioning of the cardiorespiratory system of athletes during exercise.

[Study of the impact of omega-3 PUFA on fatty acid composition of heart, respiration and swelling of mitochondria of the heart in diabetes].

We studied the influence of omega-3 polyunsaturated fatty acids (PUFAs) on respiration, swelling of rat heart mitochondria and changes in rat heart fatty acid composition in tissue homogenate in rats with streptozotocin induced diabetes mellitus (diabetes), which was induced by single intraperitoneal administration of 55 mg/kg streptozotocin. We found that application of these acids increased parameters of active mitochondrial respiration V3 at 63.7%, controlled breathing V4 at 30.7% and the rate of phosphorylation by 18.9% in animals with experimental diabetes. We proved their ability to reduce swelling of mitochondria in heart at streptozotocin induced diabetes. In addition, we established changes of fatty acid composition of cell membranes in hearts under diabetic conditions with omega-3 PUFAs influence. The obtained results allow to conclude that the omega-3 PUFA have a positive effect on functional parameters of mitochondria due to stabilization cell membranes of rat heart with diabetes.

[The changes of metabolism in myocardium at ischemia-reperfusion and activating of the ATP-sensitive potassium channels].

In experiments on the anaesthetized dogs with modeling of experimental ischemia (90 min) and reperfusion (180 min) it was investigated the changes of biochemical processes in the different areas of heart (intact, risk and necrotic zone) during intragastric introduction of medicinal form (tablets) of flocalin (the fluorine-containing opener of ATP-sensitive potassium channels) in a dose 2,2 mg/kg. The data analysis allowed to define a few possible cardioprotective mechanisms of flocalin action at ischemia-reperfusion conditions: the preservation of sufficient levels of de novo (by cNOS) NO synthesis, an inhibition of de novo (by iNOS) and salvage (by NADH-dependent nitratreductase) NO synthesis, an inhibition of L-arginine degradation by arginase, an inhibition of oxidizing metabolism due to limitation of ROS and RNS generation, inhibition of free arachidonic acid and eicosanoids synthesis, inhibition of ATP and GTP degradations and, possibly, stimulation of protective haem degradation. These changes may prevent formation of toxic peroxynitrite and suggest the possibility of participating in flocalin-mediated cardioprotective effects of warning a mitochondrial permeability transition pore (MPTP) opening and inhibition of apoptosis and/or necrosis of cardiomyocytes induced by it.

[RNA interference of proteasome subunit of PSMbeta7 gene restricts proteasome subunit PSMbeta1 and PSMbeta5 mRNA expression and peptidyl-glutamyl peptide-hydrolyzing proteasome activity in neonatal cardiomyocytes].

Using small interfering RNA (siRNA) transfection of neonatal cardiomyocytes to inhibit expression of nonproteolytic proteasome beta7 subunit, we observed a significant decrease in beta1 proteolytic subunit mRNA expression. Proteasome peptidyl-glutamyl peptide-hydrolyzing activity decreased to 28% (0.48 +/- 0.2 nM AMC/min) compared to control (1.7 +/- 0.5 nM AMC/min) (P < 0.05). Beta5 Subunit mRNA expression decreased 21 times (P < 0.05) with no changes in its chymotrypsin-like activity. Proteasome trypsin-like activity and activity of another proteolytic enzyme tripeptidyl-peptidase II remained unchanged.

[Interrelation between cardiac pump function disturbances and cardiac contractility after beta-adrenergic hyperstimulation of the heart in rats].

The complex of structural and functional changes of myocardium was investigated in experiments with rats with chronic beta-adrenergic activation for 1 month. We observed substantial attenuation of myocardial pump function, particularly reduction of stroke volume by 38.50% (P < 0.01), cardiac output by 42.38% (P < 0.01), and ejection fraction by 35.61% (P < 0.01). Furthermore, 2-fold increase of end-diastolic left ventricular pressure (P < 0.01) and rise of active relaxation constant Tau by 12.91% (P < 0.05) were observed. This indicates on an impaired diastolic function of the heart that is associated with accumulation of connective tissue elements in myocardium and increase of its end-diastolic stiffness that finally leads to cardiac pump function disturbances. Surprisingly, myocardial contractility was considerably augmented not only after the treatment with beta-adrenergic agonist but also on the 26th day after drug cessation. This phenomenon is associated with elevation of dP/dt(max) by 49.9% (P < 0.01), 2.5-fold increase of end-systolic elastance (P < 0.01) as well as maximal myocardial elastance by 42.53% (P < 0.05). It can be explained by compensatory influence of increased contractility that nevertheless failed to maintain adequate cardiac pump function and furthermore it may result in depletion of cardiac energy resource.

[Correction of lipid peroxidation and antioxidant system disorders by bioflavonoids during modeling of cholesterol atherosclerosis in rabbits].

We have studied the influence of bioflavonoids (quercetin, corvitin) on lipid peroxidation and antioxidant enzymes in the modeling of cholesterol atherosclerosis in rabbits. It has been shown that simultaneous administration of the quercetin derivative corvitin suppressed lipid peroxidation. We showed that under hypercholesterolemia, the concentration of malone dialdehyde in myocardial tissue in rabbits is significantly increased, while administration of bioflavonoids decreased the concentration of malone dialdehyde by 38.3%. Furthermore, corvitin caused activating effects on antioxidant enzymes superoxide dismutase and catalase in cardiac tissue. Our data suggest that bioflavonoids are able to suppress lipid peroxidation and prevent the decrease ofantioxidant enzymes activity in rabbits with cholesterol-rich diet induced atherosclerosis.

[Effect of medical form of flocalin on the course of myocardial reperfusion injury].

In experiments on anaesthetized dogs with modeling of experimental ischemia (90 min) and reperfusion (180 min), the cardioprotective influence of the pharmacological preconditioning caused by intragastric (with a help of catheter) introduction of medicinal form (tablets) of new fluorine-containing opener of ATP-sensitive potassium channels flocalin was shown. Flocalin was introduced in a dose 2.2 mg/kg, which in the conditions of physiological norm has a minimum influence on the parameters of cardiohemodynamic. The conducted research allowed to define the changes of these parameters during development of antiischemic protective effect of pharmacological preconditioning, caused by the medicinal form of flocalin, and describes basic cardioprotective mechanisms, related to the changes of cardiohemodynamic in the dynamics of ischemia-reperfusion of myocardium. In our opinion, to positive influences of flocalin, which are possibly related to cardioprotective action, it is possible to add the prevention of an increase of general peripheral resistance, resistance of coronal vessels of heart, and relative preservation of myocardium contractility in the period of reperfusion. Also these positive effects can be explained by moderate decrease of blood pressure that decreases the loading on the damaged heart and allows to preserve cardiac emission in the first period of ischemia. One of the major indexes of development of protective mechanism of pharmacological preconditioning caused by preischemic introduction of medicinal form of flocalin is the diminishing of infarct size of myocardium in experiments with ischemia-reperfusion of myocardium on 42.53% +/- 2.91% versus control experiments.

[Effects of ubiquitin gene silencing in anoxia-reoxygenation of cultured cardiomyocytes].

Ubiquitin-dependent proteasomal proteolysis is crucialin the turnover of cardiomyocytes functional proteins (actin, myosin, ion channels at. al.), therefore, investigation of cell death after ubiquitin (UBB) gene silencing using RNA interference and anoxia-reoxygenation (AR) modeling appears to be attractive. Cardiomyocytes were transfected by siRNA to ubiquitin gene using electroporation procedure, and then primary culture was treated by 30 min of anoxia and 60 min of reoxygenation. The number of living, necrotic and apoptotic cardiomyocytes was determined by fluorescence microscopy. The level of UBB and proteasome subunits beta5 (PSMB5) and beta9 (PSMB9) mRNA expression was estimated by real-time PCR. It was shown that UBB mRNA expression was increased by 2.1 times after AR modelling (P < 0.05). Small interference RNA injection in cell culture decreased ubiquitin, PSMB5 and PSMB9 expression by 2.4 (P < 0.05), 1.3 (P > 0.05) and 1.6 (P < 0.05) times, respectively, compared with control (scrambled siRNA introduction). At the same time, the number of living cardiomyocytes decreased to 70.26 +/- 1.54%, P<0.05, and the level of necrotic cells, apoptotic cells and cells with signs of autophagy augmented by 25.92 +/- 1.52%, (P = 0.38), 4.32 +/- 0.53% (P = 0.15) and 38.2 +/- 3.81% (P = 0.001), respectively. Ubiquitin silencing after AR (30 min/l h) increased the number of living cells by 3.7% and decreased the number of necrotic cells by 4.7% and did not alter the apoptotic and autophagic cells populations. The data obtained indicate that ubiquitin gene silencing, mRNA expression of which augmented during AR, induces necrotic and autophagic death of intact neonatal cardiomyocytes in culture, but enhances the AR resistance of these cells to some extent.

[Antiatherogenic characteristics of korvitin: effect on proteasome activity of the aorta, heart, and blood cells].

We studied the changes in proteasomal proteolisis during modelling of rabbit cholesterol-induced atherosclerosis. It was determined that in aorta the TL activity of proteasome increased 2.4-fold (P < 0.05), CTL activity increased by 43%, and PGPG--by 10%. In heart tissue it was observed the increase of CTL proteasome activity by 14%. The application of "Korvitin" (water-soluble form of quercetine) followed by considerable decrease of proteasomal activity both in tissues (aorta and heart) and leucocytes. The intensity ofatherosclerotic changes in aorta was significantly smaller. Obtained data suggest that "Korvitin" reveales angioprotective properties mediated by it effect on proteasomal proteolisis.

[Omega-3 polyunsaturated fatty acids stimulate the expression of PPAR target genes].

In experiments on isolated neonatal cardiomyocytes and hearts of adult rats we investigated the influence of polyunsaturated fatty acids (PUFA) on expression of two peroxisome proliferator-activated receptor (PPAR) target genes--fatty acid transport protein (FATP) and interleukin-1 receptor antagonist (IL-1ra). We determined that cell membranes of adult rats heart and cardiomyocytes of neonatal rats which were born by females fed with omega-3 PUFA for 4 weeks, contain more omega-3 PUFA (alpha-linolenic and docosahexaenoic acids) in comparison with the control. It was shown that omega-3 PUFA elevated FATP and IL-1ra mRNA expression in 2.25 (P = 0.07) and 8.4 (P < 0.00001) folds correspondingly in adult rats tissues. In isolated cardiomyocytes, the mRNA expression of FATP and IL-1ra were augmented 2.5 folds (P = 0.22) and 8.1 folds (P < 0.00001), accordingly. Our data show that omega-3 PUFA stimulate PPAR target genes expression and allow to permit genetic mechanisms in cardioprotective effects of omega-3 PUFA.

[SiRNA-mediated silencing of 5-lipoxygenase gene (ALOX5) reduces necrosis of neonatal cardiomyocytes in anoxia-reoxygenation].

In experiments on the primary culture of isolated neonatal rat cardiomyocytes it was determined that cardiomyocytes express ALOX5 gene encoding enzyme 5-lipoxygenase. Anoxia-reoxygenation does not affect significantly the expression of 5-lipoxygenase mRNA in cardiomyocytes. Transfection of 5-lipoxygenase-specific small interfering RNA's (siRNA) into cardiomyocytes lead to a significant reduction of 5-lipoxygenase mRNA expression in cardiomyocytes 24 hours after transfection. ALOX5 gene silencing resulted in improved viability of cell population (by 13.3% P < 0.001) due to decreased number of necrotic (by 14.6%, P < 0.001), but not apoptotic, cells during anoxia-reoxygenation. Our results indicate that siRNA against ALOX5 effectively protects cardiomyocytes against anoxia-reoxygenation injury.