Neuroprotective Activity of D-HES in Transient Global Cerebral Ischemia in Rats.

We studied the effect of O-((((4-hydroxy-3,5-di(1,7,7-trimethylbicyclo[2.2.1]hept-exo-2-yl) benzyl)oxy)ethyl)-O-(2-hydroxyethyl)-(1→4)-α-D-glucan (D-HES, 80 mg/kg, intravenously) and reference preparation ethylmethylhydroxypyridine succinate (EMHP-S, 50 mg/kg, intravenously) on rat survival and neurological deficit in 24 h after transient global cerebral ischemia in Wistar rats. Intravenous administration of D-HES and EMHP-S significantly increased the number of survivors by 68 and 78%, respectively, in comparison with the control group. In groups treated with D-HES and EMHP-S, the number of animals with severe neurological deficit was significantly lower and the number of animals moderate or mild neurological deficit was significantly higher than in the control group.

Brattleboro Rats as the Model of Blood Hyperviscosity Syndrome for Testing Substances with Hemorheological Activity.

Hyperviscosity syndrome was described in Brattleboro rats. The aim of this study was to investigate the possibility of Brattleboro rats using, as a test system for the study of agents with hemorheological activity. Under conditions of this model of high blood viscosity syndrome in Brattleboro rats, Lychnis chalcedonica L. extract (150 mg/kg) administered intragastrically for 10 days exhibited hemorheological activity by modulating macro- (plasma viscosity, fibrinogen concentration) and microrheological (erythrocyte aggregation and deformability parameters. Hence, Brattleboro rats are an adequate model of hyperviscosity syndrome that can be used for search and testing of substances with hemorheological activity.

[Effect of Rhaponticum carthamoides extract in combination with dosed physical load on hemorheological parameters of rats with myocardial infarction].

The administration of the extract from Rhaponticum carthamoides (150 mg/kg, p.o., for 10 days) in combination with dosed low-power exercise in rats with experimental myocardial infarction led to an improvement of hemorheological indices, which was manifested by a decrease in the whole blood viscosity, aggregation of erythrocytes, and increase in erythrocyte deformability. In particular, the extract from R. carthamoides contributed to an increase in the hematocrit/blood viscosity, which was indicative of an improvement of the blood overall oxygen transport capacity. In addition, administration of the extract in combination with dosed exercise favored normalization of the lactate and pyruvate concentrations in blood of rats with myocardial infarction.

[Effects of flaxseed extract on rheological properties of blood in experimental ovariectomy].

The effect of flaxseed extract (FSE) containing 42% secoisolariciresinol diglucoside on the blood plasma estradiol level and theological properties of blood in female Wistar rats after ovariectomy was investigated by measuring hematocrit, fibrinogen concentration, platelet aggregation and deformability, and the whole blood and plasma viscosity. Bilateral ovariectomy in rats led (in comparison to sham-operated animals) to a decrease in the estrogen level to 59% and produced a 5-9% increase in the whole blood viscosity, which was caused by impairment of the erythrocyte deformability and aggregation. The efficacy of oxygen transport to tissues was decreased by 4-7%. The treatment of ovariectomized rats with FSE (peroral administration at a daily dose of 40 mg/kg for 14 days) reduced the whole blood viscosity by 4-11% and increased the coefficient of oxygen transport to tissues by 5-11%, but did not restore the estrogen level. Thus, the hemorheological effect of FSE reduces to the improvement of microrheological parameters (decrease in erythrocyte aggregation and increase in their deformability) without the modification ofmacrorheological parameters (hematocrit, plasma viscosity and fibrinogen level).

[Methodological approaches to studying substances influencing blood rheology].

Optimum design of preclinical research for pharmacological agents influencing the rheological properties of blood is presented. Models of hyperviscosity syndrome and approaches to studying the hemorheological activity mechanisms are described.

Antithrombogenic and antiplatelet activities of extract from Maackia amyrensis wood.

Antithrombogenic and antiplatelet effects of a new drug, containing isoflavonoids (extract from the wood of Maackia amyrensis, a Far Eastern plant), were studied. A course (200 mg/kg intragastrically during 14 days) of Maackia amyrensis extract prevented intravascular clotting, initiated by application of 10% iron chloride solution on the vessel. The drug increased antiaggregant activity of the vascular wall and potentiated endothelium-dependent vasodilatation in ovariectomied rats. The reference drug ethinylestradiol (25 mug/kg intragastrically during 14 days) potentiated the antiaggregant effect of the endothelium, but was inferior to Maackia amyrensis extract in the capacity to induce endothelium-dependent vasodilatation in ovariectomied rats.

Effect of Rhaponticum carthamoides extract on structural and metabolic parameters of erythrocytes in rats with cerebral ischemia.

Cerebral ischemia in rats was accompanied by an increase in erythrocyte degradation, which results from changes in lipid composition of their membranes. The content of lipids and phospholipid fraction (phosphatidylcholine, sphingomyelin, and phosphatidylserine) decreased, while the relative content of lysophospholipids increased in erythrocyte membranes. The course of treatment with Rhaponticum carthamoides extract (150 mg/kg perorally, 5 days) contributed to an increase in the contents of total lipids and phospholipids (primarily of sphingomyelin and phosphatidylserine) and decrease in the ratio of lysophospholipids in the erythrocyte membrane of rats with cerebral ischemia. Morphological characteristics of erythrocytes returned to normal, which manifested in an increase in the number of discocytes and decrease in the count of degenerated cells.

Effect of Alchemilla vulgaris extract on the structure and function of erythrocyte membranes during experimental arterial hypertension.

The course of treatment with Alchemilla vulgaris extract increased the concentrations of lipids and phospholipids in erythrocyte membranes, decreased the number of abnormal erythrocytes, and improved deformability of red blood cells in rats with arterial hypertension.

[Cerebroprotector activity of Rhaponticum carthamoides extract in rats with brain ischemia].

Electron microscopy and electrophysiological data reveal pronounced structural and functional disturbances in cerebral cortex of rats with model brain ischemia. A 5-day treatment with a dry extract from Rhaponticum carthamoides (Willd.) Iljin. in a daily dose of 150 mg/kg (p.o.) equivalent to 2.7 mg ecdysterone per kg body weight reduced manifestations of the ischemic damage, improved the structure of neurons, and restored brain activity (EEG parameters).

Hemorheological and cerebroprotective activity of Lychnis chalcedonica L. extract in rats with cerebral ischemia.

Considerable hemorheological changes and depression of EEG parameters were revealed in rats with cerebral ischemia. Course peroral treatment with scarlet lightning extract in a daily dose of 150 mg/kg for 5 days reduced the severity of hemorheological disorders. It manifested in a decrease in whole blood viscosity, plasma viscosity, erythrocyte aggregation, and fibrinogen concentration and increase in deformability. The extract of lightning extract improved EEG activity in rats with cerebral ischemia.

Correction of the high blood viscosity syndrome by a mixture of Diquertin and Ascorbic Acid in vitro and in vivo.

Diquertin was shown to diminish blood viscosity, to decrease the aggregation of erythrocytes, and to increase their deformability using a model of the high blood viscosity syndrome in vitro. A mixture of Diquertin with Ascorbic Acid was more effective in improving rheological indicators of blood, then either Diquertin or Tanakan. On a model of chronic brain ischemia, which is accompanied by significant deterioration of the rheological properties of blood, it was shown that a therapy with a mixture of Diquertin and Ascorbic Acid decreases the expression of the high blood viscosity syndrome.

Correction of haemorheological disturbances in myocardial infarction by diquertin and ascorbic acid.

In a model of the high blood viscosity syndrome, developed after myocardial infarction in rats, it was observed that a therapy of a combination of diquertin (20 mg/kg) and ascorbic acid (50 mg/kg) for a -period of 6 days, resulted in an improvement of haemorheological indices. The decrease in blood -viscosity was primarily due to an improved deformability of erythrocytes, and to some extent, due to a decrease in the content of plasma fibrinogen and erythrocyte aggregation.

Ischemia-induced changes in synaptoarchitectonics of brain cortex and their correction with ascovertin and Leuzea extract.

Peroral administration of 70 mg/kg ascovertin and 150 mg/kg Leuzea extract to rats with cerebral ischemia for 5 days prevented destructive changes and decrease in the density of synapses in the cerebral cortex. These preparations activated compensatory and reparative mechanisms underlying plasticity of the synaptic pool, which was realized through hypertrophy and destruction of synaptic contacts. Ascovertin possessed more pronounced cerebroprotective activity than Leuzea extract.

[Effect of Rhaponticum carthamoides extract on hemorheological properties of blood in rats with arterial hypertension]. / Vliianie ekstrakta levzei salorovidnoi na reoloigheskie svoistva krovi u krys s arterial'noi gipertenzei.

The hemorheological activity of a dry extract from Rhaponticum (Leuzea) carthamoides (Willd.) Iljin. was studied in spontaneously hypertensive rats (SHRs). A 14-day treatment of the test rats with a daily dose of 150 mg/kg improved the rheological characteristics, as manifested by a reduced viscosity of the whole blood and plasma, increased spontaneous erythrocyte aggregation and fibrinogen concentration, and increased erythrocyte deformability and electrophoretic mobility against the untreated control level.

[The hemorheological effects of Lychnis chalcedonica L. extracts]. / Gemoreologicheskie éffekty ékstraktov Lychnis chalcedonica L.

The hemorrheological effects of extracts from Maltese cross campion (Lychnis chalcedonica L.) prepared using 40% (I) and 70% (II) aqueous ethanol solutions were studied in vitro in comparison with tanakan on the model of high blood viscosity syndrome. Under the hyperthermia conditions, extracts I and II at a concentration of 1 x 10(-5) g/ml limited the growth of blood viscosity and thrombocyte aggregation and the drop in thrombocyte deformability. The effects of both extracts were comparable to those of tanakan. Prolonged (5 days) administration of extract I (daily dose, 150 mg/kg p.o) in rats with arterial hypertension (SHR) decreased the viscosity of whole blood and plasma, reduced the concentration of fibrinogen, and increased the deformability of erythrocytes. No reliable effects of the extracts in vivo upon the erythrocyte aggregation and hematocrit were observed.

[The correction of the increased blood viscosity syndrome in brain ischemia in rats with a combination of dikvertin and ascorbic acid]. / Korrektsiia sindroma povyshennoi viazkosti krovi v usloviiakh ishemii mozga u krys kompleksom dikvertina i askorbinovoi kisloty.

In experiments in vitro on a model of the syndrome of increased blood viscosity dikvertin reduced blood viscosity, weakened aggregation of red cells and raised their property of becoming distorted. A mixture of dikvertin and ascorbic acid improved the hemorrheologic parameters better than do dikvertin and tanakan. On a model of chronic ischemia of the brain of rats attended with deterioration of blood rheologic parameters, it was demonstrated that a course of treatment with a dikvertin and ascorbic acid complex decreases the manifestations of the syndrome of increased blood viscosity.