Neuroprotective Effectiveness of Intravenous Ubiquinone in Rat Model of Irreversible Cerebral Ischemia.

The neuroprotective effect of ubiquinone (coenzyme Q10)was demonstrated on the rats model of ischemic stroke provoked by persistent 24-h occlusion of the middle cerebral artery. Coenzyme Q10 (30 mg/kg) was injected intravenously in 60 min after artery occlusion. Ubiquinone crossed the blood-brain barrier, accumulated in the brain, and produced a neuroprotective effect: it alleviated ischemia-induced neurological deficit and reduced the size of necrotic zone by 49% in comparison with rats receiving physiological saline.

[COMPARATIVE CARDIOPROTECTIVE EFFICACY OF COENZYME Q10 AND MEXICOR IN EXPERIMENTAL MODEL OF MYOCARDIAL INFARCTION IN RATS].

Cardioprotective efficacy of coenzyme Q10 (CoQ10, ubidecarenone) and mexicor were evaluated on the 21st day of experimental myocardial infarction in Wistar rats. CoQ10 or mexicor were injected in a dose of 30 mg/kg intravenously 10 min after coronary artery occlusion. The observed cardioprotective effects of ubidecarenone and mexicor were close. Both drugs equally increased the survival of rats, prevented the development of dilatation and hypertrophy of the left ventricle, and improved the pump cardiac function.

[Hplc estimation of coenzyme Q(10) redox status in plasma after intravenous coenzyme Q(10) administration].

The pharmacokinetics of the total pool of coenzyme Q(10) (Co(10)), its oxidized (ubiquinone) and reduced (ubiquinol, CoQ(10)H2) forms have been investigated in rats plasma during 48 h after a single intravenous injection of a solution of solubilized CoQ(10) (10 mg/kg) to rats. Plasma levels of CoQ(10) were determined by HPLC with spectrophotometric and coulometric detection. In plasma samples taken during the first minutes after the CoQ(10) intravenous injection, the total pool of coenzyme Q(10) and proportion of CoQ(10)H2 remained unchanged during two weeks of storage at -20°C. The kinetic curve of the total pool of coenzyme Q(10) corresponds to a one-part model (R² = 0.9932), while the corresponding curve of its oxidized form fits to the two-part model. During the first minutes after the injection a significant portion of plasma ubiquinone undergoes reduction, and after 7 h the concentration of ubiquinol predominates. The decrease in the total plasma coenzyme Q(10) content was accompanied by the gradual increase in plasma ubiquinol, which represented about 90% of total plasma CoQ(10) by the end of the first day. The results of this study demonstrate the ability of the organism to transform high concentrations of the oxidized form of CoQ(10) into the effective antioxidant (reduced) form and justify prospects of the development of parenteral dosage forms of CoQ(10) for the use in the treatment of acute pathological conditions.

[Intravenous injection of coenzyme Q10 increases its level in rat brain].

It is established that intravenous injection of solubilized coenzyme Q10 provides quick and lasting increase in its level in the brain as compared to control intact rats and those with cerebral ischemia. These new data provide a basis for studying the efficacy of coenzyme Q10 as a neuroprotective agent in ischemic stroke.

[Effect of coenzyme Q10 on rat myocardiumin the acute stage of experimental infarction].

The influence of coenzyme Q10 (CoQ10) on early ischemic deterioration was studied on Wistar rats with experimental myocardial infarction. CoQ10 (30 mg/kg) was injected intravenously 10 min after coronary artery occlusion, and morphometric analysis was performed for 72 h after the onset of ischemia. CoQ10-treated rats had restricted total myocardial damage (by 52%), including areas of necrosis (by 84%) and areas of cellular inflammatory infiltration (by 38%) as compared to saline-treated rats (p < 0.001).

[New antioxidants as neuroprotective agents for the treatment of ischemic brain injury and neurodegenerative diseases].

Central nervous system disorders are the leading cause of mortality and disability in the world. Unfortunately, the possibility of pathogenetic therapy is limited and it is important to search for new drugs with neuroprotective mechanism of action. One of the most promising groups of drugs are antioxidants--substances that can neutralize free radicals and reduce oxidative stress. This review focuses on preclinical and clinical studies of new antioxidants.

Single intravenous injection of coenzyme Q10 protects the myocardium after irreversible ischemia.

Experiments were performed on the model of irreversible myocardial ischemia in Wistar rats. Coenzyme Q10 was injected intravenously 10 min after coronary artery occlusion. On day 21 after myocardial infarction the content of coenzyme Q10 in the left ventricle, liver, and plasma from animals of the treatment group was higher than that in untreated rats by 23, 1042, and 87%, respectively (p<0.05). The area of the necrotic zone was lower, and postinfarction hypertrophy of the left ventricle was less pronounced in coenzyme-receiving rats. Right ventricular hypertrophy did not develop in these animals. These rats were characterized by greater stroke volume (by 24.6%, p<0.05), stroke work (by 34.9%), cardiac output (by 37.8%, p<0.05), ejection fraction (by 35.7%, p<0.05), and contractility (by 22.5%, p<0.05), but lower end-diastolic pressure (by 25.8%, p<0.05) than untreated animals. These data indicate that the development of parenteral ubiquinone preparations holds much promise for urgent therapy of acute cardiovascular disorders.

[Coenzyme Q10 single intravenous infusion protects rat myocardium against subsequent ischemia/reperfusion].

Cardioprotective effects of coenzyme Q10 (CoQ10) injected intravenously 30 min before coronary artery occlusion were assessed on the model of myocardial ischemia/reperfusion in Wistar rats. Rats treated with CoQ10 after 30 min of ischemia and 120 min of reperfusion exhibited smaller (by 35%, p < 0.01) size of irreversibly damaged myocardium, shorter duration and decreased number of arrhythmias during reperfusion, and increased content of myocardial CoQ10 (by 210%, p < 0.01) as compared to saline-treated rats. Increased CoQ10 levels in myocardium were accompanied by smaller size of damaged myocardium (r = -0.77, p = 0.0002). Thus, there is evidence of the cardioprotective effect of CoQ10 injected intravenously before myocardial ischemia/reperfusion.

Pharmacokinetics of coenzyme q10.

The pharmacokinetics of coenzyme Q10 powder and solution of solubilized form was studied after their oral administration to rats (10 mg/kg). Plasma concentrations of coenzyme Q10 were measured by HPLC with electrochemical detection over 48 hours. Solubilized coenzyme Q10 exhibited high absorption creating higher plasma concentrations of the drug, as a result of which its bioavailability constituted 264% of that for the powder.

[Antioxidant and prooxidant action of nitric oxide donors and metabolites].

It has been shown that various nitric oxide donors and metabolites have similar effects on lipid peroxidation in rat myocardium homogenate. The formation of malondialdehyde, a secondary product of lipid peroxidation, was inhibited in a dose-dependent manner by PAPA/NONO (a synthetic nitric oxide donor), S-nitrosoglutathione, nitrite, and nitroxyl anion. The inhibition of lipid peroxidation was provided most efficiently by the administration of dinitrosyl-iron complexes with dextran and PAPA/NONO. S-nitrosoglutathione also inhibited the destruction of coenzymes Q9 and Q10 during free radical oxidation of myocardium homogenate. Low-molecular-weight dinitrosyl iron complexes with cysteine also promoted lipid peroxidation, which is probably due to iron release during the destruction dinitrosyl iron complexes. It is likely that the antioxidant action of nitric oxide derivatives is related to the reduction of ferry forms of hemoproteins and interaction of nitric oxide with lipid radicals.

[Depression as a side effect of alpha-interferon: mechanisms of development and criteria for experimental evaluation].

Possible mechanisms of the development of depression as a side effect of the a-interferon are reviewed. Methods used for the characterization of depressive states in experiment are considered.

Chronic administration of coenzyme Q10 limits postinfarct myocardial remodeling in rats.

The effect of chronic coronary artery occlusion on the content of rat myocardial coenzymes Q (CoQ) and evaluation of the applicability of CoQ(10) for limiting postinfarct remodeling have been investigated. Left ventricle myocardium hypertrophy was characterized by the decrease in CoQ(9) (-45%, p < 0.0001), CoQ(10) (-43%, p < 0.001), and alpha-tocopherol (-35%, p < 0.05). There were no differences between the parameters of postinfarction and sham-operated rats in plasma. Administration of CoQ(10) (10 mg/kg) via a gastric probe for 3 weeks before and 3 weeks after occlusion maintained higher levels of CoQ in the postinfarction myocardium: the decrease in CoQ(9) and CoQ(10) was 25% (p < 0.05) and 23% (p < 0.05), respectively (versus sham-operated animals). Plasma concentrations of CoQ(10) were more than 2 times higher (p < 0.05). In CoQ treated rats there was significant correlation between plasma levels of CoQ and the infarct size: r = -0.723 (p < 0.05) and r = -0.839 (p < 0.01) for CoQ(9) and CoQ(10). These animals were also characterized by earlier and more intensive scar tissue formation in the postinfarction myocardium and also by more pronounced cell regeneration processes. This resulted in the decrease in both the infarct size (16.2 +/- 8.1 vs. 27.8 +/- 12.1%) and also mass index of left ventricle (2.18 +/- 0.24 vs. 2.38 +/- 0.27 g/kg) versus untreated rats (p < 0.05). Thus, long-term treatment with ubiquinone increases plasma and myocardial CoQ content and this can improve the survival of myocardial cells during ischemia and limit postinfarct myocardial remodeling.

[Effect of ubiquinone on contractile function and antioxidant status of the myocardium in spontaneously hypertensive rats].

During the period of aging of spontaneously hypertensive rats (SHR) between 6 and 13 weeks the systolic arterial pressure increased from 131+/-2 up to 176+/-3 mm Hg while in the control group of WKY rats it reached 122+/-2 mmHg. The hypertension was combined with myocardial hypertrophy -- the relative weight of SHR heart was 24% higher. The contractile myocardial function of the isolated isovolumic heart of SHR group did not differ from WKY group in a wide range of coronary perfusion rates. During oxidative stress induced by 40-min intracoronary introduction of H(2)O(2) function of hypertrophied SHR hearts fell significantly deeper. This coincided with decreased myocardial activity of superoxide dismutase and glutathione peroxidase by 29-30%, and increased catalase activity by 18%. The rate of generation of active forms of oxygen (hydroxyl radicals HO(.-)) in mitochondria from SHR hearts was higher as compared with WKY. Thus, the development of hypertension was combined with decreased antioxidant protection of the myocardium. The addition of ubiquinone to drinking water (approximately 10 mg/kg/day) for 6 weeks did not affect arterial pressure level, but was associated with two times lesser degree of myocardial hypertrophy. The hearts of SHR that received ubiquinone differed from those not treated with ubiquinone by increased maximal level of myocardial contractile function, and by improved myocardial relaxability and distensibility. After administration of H(2)O(2), myocardial function of SHR was kept on higher level. That was combined with less myocardial oedema, better preservation of antioxidant enzymes and reduced rate of succinate-dependent generation of superoxide radicals in mitochondria from hearts of ubiquinone treated SHR. The results have shown, that administration of ubiquinone to rats with hereditary hypertension reduces degree of myocardial hypertrophy, improves functional properties of the myocardium, promotes effective protection of antioxidant enzymes and increases the resistance of the cardiac muscle to oxidative stress.

Changes in antioxidant status of myocardium during oxidative stress under the influence of coenzyme Q10.

Changes in myocardium were studied during oxidative stress induced by infusion of hydrogen peroxide in the coronary vessels of isolated rat heart. Moderate concentrations of H2O2 increased the heart rate but decreased the contractile force, whereas higher concentrations of H2O2 decreased both parameters and increased the end diastolic pressure. The effect of H2O2 was stable, cumulative, and was associated with disturbance in respiration of mitochondria, increased production of ROS in them, and decrease in activities of antioxidant enzymes in the myocardium. Changes in the antioxidant status of the myocardium induced by long-term addition of coenzyme Q(10) into food was accompanied by decrease in the negative inotropic effect of H2O2, whereas the levels of superoxide dismutase and glutathione peroxidase after oxidative stress were virtually unchanged. The activities of these enzymes displayed a high positive correlation with the cardiac function. The findings suggest that coenzyme Q(10) should increase resistance of the myocardium to oxidative stress not only by a direct antioxidant mechanism but also indirectly, due to increased protection of antioxidant enzymes.

Protection of rat myocardium by coenzyme Q during oxidative stress induced by hydrogen peroxide.

Ubiquinone Q(10) (coenzyme Q) is an important component of the mitochondrial electron transport chain and an antioxidant. The purpose of this work was to find out whether an increase in the level of coenzyme Q in the heart changes its maximal working capacity and resistance to oxidative stress. Male Wistar rats were treated with coenzyme Q (10 mg/kg body weight per day) for six weeks, and this increased its content in the myocardium by 63%. The myocardial content of malonic dialdehyde and activities of key antioxidant enzymes were unchanged, except nearly 2.5-fold decrease in the activity of superoxide dismutase. The maximal working capacity of the isolated isovolumic heart did not change, but under conditions of oxidative stress induced by 45-min infusion of hydrogen peroxide (70 micro M) into coronary vessels the contractile function of these hearts decreased significantly more slowly. This was associated with less pronounced lesions in the ultrastructure of cardiomyocytes and lesser disorders in the oxidative metabolism of mitochondria that suggested increased antioxidant protection of the myocardium.

Role of reactive oxygen species in the sensitivity of rat hypertrophied myocardium to ischemia.

The relationship between hydroxyl radical (OH*) generation in the zone of ischemia/reperfusion and the size of infarction formed was investigated in 18-22-week-old anaesthetized male SHRSP and Wistar rats using a myocardial microdialysis technique. The marker of OH* generation, 2,3-dihydroxybenzoic acid (2,3-DHBA), was analyzed in dialyzates by high performance liquid chromatography with electrochemical detection. Myocardial ischemia was induced by ligation of the descending branch of the left main coronary artery for 30 min. The mean value of basal 2,3-DHBA level in the dialyzate samples from SHRSP (243 +/- 21 pg for 30 min) was significantly higher than that from Wistar rats (91 +/- 4 pg for 30 min, p < 0.0002); it positively correlated with left ventricular hypertrophy (r = 0.806; p < 0.05). During reperfusion total 2,3-DHBA output was 1.8-fold higher in SHRSP than in Wistar rats (659 +/- 60 pg versus 364 +/- 66 pg for 60 min, respectively, p < 0.0002). At the same time, 2,3-DHBA increase above the basal level was the same in Wistar and SHRSP rats (181 +/- 25 and 172 +/- 36 pg for 60 min, respectively). The infarct size in SHRSP (45.4 +/- 4.3%) was significantly higher (p < 0.05) than in Wistar rats (32.8 +/- 3.3%). There was a significant positive correlation between basal level of 2,3-DHBA and total reperfusion 2,3-DHBA content in SHRSP (r = 0.752; p < 0.05). Thus, data obtained clearly indicate that the hypertrophied myocardium of SHRSP was less tolerant to ischemia/reperfusion than that of Wistar rats due to chronically increased OH* production and enhanced total OH* output during reperfusion. Greater myocardial damage in SHRSP than in Wistar rats following the equal increase in OH* production above the basal level suggests the existence of deficit of the antioxidant defense in the hypertrophied myocardium.

[Effect of phenyl-tert-butylnitrone, mexidol and nooglutil on the ischemic lesion zone and memory in rats following middle cerebral artery occlusion]. / Vliianie fenil-t-butilnitrona, meksidola i noogliutila na zonu ishemicheskogo porazheniia mozga i pamiat' krys posle okkliuzii srednei mozgovoi arterii.

An ischemic cerebral affection zone amounting to 22.51 +/- 3.0% of the ipsilateral hemisphere volume was found on the frontal brain sections in the frontoparietal cortex of rats 72 h after occlusion of the distal branch of the medial cerebral artery. The new nootropic drug nooglutyl [N-(5-hydroxynicotinoyl)-L-glutamic acid] in a dose of 10 mg/kg, as well as mexidol or phenyl-tert-butylnitrone (PBN) in a dose of 100 mg/kg, introduced into the vein at the moment of occlusion and intraperitoneally for two days after operation, effectively restricted the affected zone: nooglutyl, up to 7.6 +/- 2.28%; mexidol, up to 9.55 +/- 1.9%; and PBN, up to 12.8 +/- 1.7% of the ipsilateral hemisphere volume. On the third day after operation, animals preliminarily learnt to the passive avoidance conditioned reflex exhibited violated memory retrieval. The retrieval was significantly improved in the test animals treated with mexidol and especially nooglutyl.

[Increased generation of hydroxyl radicals in the rat hypertrophied myocardium: in vivo study by microdialysis]. / Usilennaia produktsiia gidroksil'nykh radikalov v gipertrofirovannom miokarde krysy: mikrodializnoe islledovanie in vivo.

A comparative study of the generation of hydroxyl radicals (OH*) in the hypertrophic myocardium of SHR-SP rats (n = 8) and in the myocardium of WKY (n = 5) and Wistar (n = 12) rats was performed using the microdialysis technique. The experiments were carried out on anesthetized open-chest male rats (ketamine intraperitoneally, 10 mg/kg) with artificial ventilation. The amount of OH* produced was estimated by high-performance liquid chromatography with electrochemical detection using as a marker 2,3-dihydroxybenzoic acid (2,3-DHBA), a product of the reaction of the hydroxyl radical with salicylic acid added to the perfusate. The quantity of 2,3-DHBA in the dialysate was estimated by the external standard method and expressed in percent of the 2,3-DHBA concentration in the perfusion fluid. The mean baseline value of 2,3-DHBA in dialysate samples in SHR-SP rats (157 +/- 22%, n = 8) was significantly higher than in Wistar (90 +/- 15%, n = 12, p = 0.0001) and Wistar-Kyoto rats (106 +/- 12%, n = 5, p = 0.005). The basal 2,3-DHBA level in SHR-SP rats was positively correlated (r = 0.831, n = 7, p < 0.05) with the degree of hypertrophy of the left ventricle expressed as the ratio of the left ventricle weight to the body weight. The data presented demonstrate that the hypertrophy of the left ventricle in SHR-SP rats is accompanied by the elevation of the level of free oxygen radicals.

Formation of hydroxyl radicals during myocardial reperfusion after experimental ischemia of different duration.

The intensity of hydroxyl radical (OH*) formation in the myocardium during reperfusion after ischemia of different duration was evaluated using microdialysis with sodium salicylate. 2,3-Dihydroxybenzoic acid, a product of OH* trapping by salicylic acid, was used as a marker of OH* generation in the postischemic myocardium. Experiments were performed on open-chest anesthetized and jet-ventilated Wistar rats. The concentrations of 2,3-dihydroxybenzoic acid in the dialysate were measured by high performance liquid chromatography (HPLC) with electrochemical detection. Experiments showed that the intensity and duration of free oxygen radical generation during reperfusion after 30-min ischemia far surpassed those observed after 20-min ischemia.