Erythrocyte deformability and aggregation in morbidly obese women undergoing laparoscopic gastric bypass surgery and effects of oral omega-3 fatty acid supplementation.

BACKGROUND: An adequate erythrocyte function is vital for tissue oxygenation and wound healing. The erythrocyte membrane phospholipid composition plays an important role in erythrocyte function and administration of omega-3 fatty acids may provide a means to improve it. OBJECTIVE: To investigate peri-operative erythrocyte function and effects of oral omega-3 fatty acids in morbidly obese women undergoing gastric bypass surgeryMETHODS:Fifty-six morbidly obese women undergoing laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery were randomized between a low calorie diet (LCD) during 2 weeks or oral omega-3 poly-unsaturated fatty acids (n-3 PUFAs) and a normal diet during 4 weeks. Peri-operative blood samples were analyzed with the Lorrca MaxSIS Ektacytometer for erythrocyte deformability and aggregability. RESULTS: There were no significant differences in erythrocyte function between the groups at any time point. Only erythrocyte aggregability parameters were affected by surgery. At six month follow-up, aggregation index (AI) and cholesterol, glucose and insulin were significantly improved. CONCLUSIONS: In this study, oral Omega-3 supplementation did not affect erythrocyte function compared to a LCD. Six months after surgery a significant improvement in AI and metabolic parameters was observed in both groups, contributing to a reduction in the risk at thromboembolic and cardiovascular complications.

Erythrocyte deformability and aggregability in patients undergoing colon cancer surgery and effects of two infusions with omega-3 fatty acids.

BACKGROUND: An adequate erythrocyte function is vital for tissue oxygenation and wound healing. The erythrocyte membrane phospholipid composition plays an important role in erythrocyte function and administration of omega-3 fatty acids may provide a means to improve it. OBJECTIVE: To investigate peri-operative erythrocyte function and effects of omega-3 fatty acidsMETHODS:Forty-four patients undergoing elective laparoscopic colon resection for non-metastasized cancer were randomized between intravenous omega-3 poly-unsaturated fatty acids (n-3 PUFAs) or placebo (saline). Peri-operative blood samples were analyzed with a Lorrca MaxSIS Ektacytometer and erythrocyte membrane phospholipids were determined with gas chromatography. RESULTS: Patient and operation characteristics were equal between groups. There was a significant increase in erythrocyte membrane eicosapentaenoic acid (EPA) but not docosahexaenoic acid (DHA) in the n-PUFA group. There were no significant differences in erythrocyte deformability but the aggregation index (AI) was significantly lower and the aggregation half time (T½) was significantly higher in the n-3 PUFA group. CONCLUSION: This study confirms rapid changes in erythrocyte membrane phospholipid composition after administration of intravenous n-3 PUFAs. Erythrocyte deformability parameters were not affected but erythrocyte aggregability was decreased in the n-3 PUFA group. Further investigation is necessary to gain more insights in the effects of n-3 PUFA and the postoperative inflammatory response on erythrocyte function.

Effects of Ankaferd Hemostat on red blood cell aggregation: a hemorheological study

Background/aim: Ankaferd hemostat (ABS; Ankaferd blood stopper, Istanbul, Turkey) is a prohemostatic agent affecting erythrocytes. The hemostatic action of ABS depends upon fibrinogen gamma chain, prothrombin, and red blood cells. The aim of this study was to assess the effects of ABS on erythrocyte aggregation via hemorheological analyses. Materials and methods: To measure erythrocyte aggregation, blood samples were obtained from healthy, nonsmoker volunteers who had not taken any medication in the previous 10 days. One mL of blood was placed into the laser-assisted optical rotational cell analyzer (LORCA), into the chamber formed by the gap between two concentric glass cylinders. The solution prepared with ABS and saline was added to blood in incremental amounts of 10 µL, 20 µL, 30 µL, 40 µL, 50 µL, 60 µL, 70 µL, and 100 µL. Erythrocyte aggregation was determined by laser-assisted optical rotational cell analyzer at 37 °C Results: AMPwas found to be 17.7 ± 2.1 au in the blood without ABS, whereas it was lower in the blood with ABS. AMP was 16.0 ± 3.3 in the ABS-added blood group. RBC aggregates did not form faster when cells contacted ABS. The t t½ value was 4.6 ± 2.6 in the ABS-added blood group and 1.9 ± 0.20 in the control group. Aggregation was faster in the control group (P = 0.03). AI, which is a combination of AMP and t½, was lowered in the ABS group (48.7 ± 12.3) compared to the control group (65.8 ± 1.6) (P = 0.02). It was notable that the γIsc max (sec-1) value of the control was higher (200 ± 106) than the ABS-added blood group (141 ± 51.0). Conclusion: ABS has antierythroid aggregation effect. ABS inhibits pathological aggregation of red blood cells. Antithrombotic clinical effects of ABS may be ascribed to the antierythroid aggregan actions of the drug.

Acute L-Arginine supplementation does not affect red blood cell aggregation and deformability during high intensity interval exercise in healthy men.

BACKGROUND: L-Arginine, the precursor of NO might be involved in improving the cardiovascular disorders via regulation of functional properties of erythrocytes. OBJECTIVE: This study investigated the effects of L-Arginine supplementation on responses of red blood cell (RBC) properties to high intensity interval exercise (HIIE). METHODS: Ten overweight healthy men participated voluntarily in the study and performed two HIIE trials with and without L-Arginine in two separate weeks. The HIIE protocol included 12 intervals of 3-min encompassed 1-min running at 100% of vVO2max and 2-min active recovery at 40% of vVO2max. Three blood samples were taken before and after supplementation, and immediately after exercise; and were used to measure red blood cell properties. RESULTS: The HIIE protocol increased hematocrit, hemoglobin and lactate significantly (P < 0.05), but had no significant effect on RBC aggregation, RBC deformability, and fibrinogen concentration. When data were compared for two trials no significant differences between the responses of RBC properties to two HIIE protocols were detected (P > 0.05), whereas the increases in lactate concentration following HIIE was significantly lower in L-Arginine than placebo trial (P < 0.05). CONCLUSIONS: It is concluded that L-Arginine consumption prior to HIIE does not lead to any improvement in RBC properties during HIIE in overweight healthy men.

Investigation of the effects of major ozone autohemotherapy application on erythrocyte deformability and aggregation.

BACKGROUND: Ozone is used intensively worldwide in treatment and research of various pathologies due to its healing effects. OBJECTIVE: The aim of this study is to investigate the effect of major ozone autohemotherapy on erythrocyte deformability and aggregation. METHODS: 10 and 50µg/ml doses of ozone was applied for 20 minute to venous blood samples obtained from 10 healthy male volunteers. Erythrocyte aggregation, deformability were measured by an ektacytometer. Total oxidant status, total antioxidant status were measured via a commercial kit. The oxidative stress index was calculated. RESULTS: Ozone at 10 and 50µg/ml doses did not alter erythrocyte aggregation. 50µg/ml ozone increased red blood cell (RBC) deformability measured at 0.53 Pa. Compared with the Control value, there was a significant increase in TOS, TAS for the doses of 10 and 50µg/ml. The increase in TAS was found to be more significant at 10µg/ml dose. The most obvious increase in OSI value was observed at 50µg/ml. CONCLUSION: Our results demonstrate that although 10µg/ml ozone has no effect on hemorheology, 50µg/ml ozone concentration has positive effects on RBC deformability, thus circulation at 0.53 Pa corresponding to the shear stress encountered during venous circulation.

Effects of Histidine-rich glycoprotein on erythrocyte aggregation and hemolysis: Implications for a role under septic conditions.

The apoptotic process of erythrocytes is known as eryptosis, and is characterized by phosphatidylserine (PS) expression on the outer membrane. PS-positive erythrocytes are increased in sepsis, and PS is believed to facilitate coagulation of erythrocytes and activate macrophages. However, the relationship between eryptosis and abnormal coagulation in sepsis is still not fully understood. Histidine-rich glycoprotein (HRG) inhibits immunothrombus formation by regulating neutrophils and vascular endothelial cells. In the present study, we subjected isolated erythrocytes to Zn2+ stimulation, which activated their aggregation and PS expression. We then determined the Zn2+ contents in septic lung and kidney tissues, and found that they were elevated, suggesting that eryptosis was enhanced in these tissues. Erythrocyte adhesion to endothelial cells was also significantly increased after Zn2+ stimulation, and this effect was inhibited by HRG. Finally, we examined HRG treatment in septic model mice, and found that HRG decreased hemolysis, possibly due to its ability to bind heme. Our study demonstrated a novel Zn2+-initiated aggregation/thrombus formation pathway. We also showed the regulatory role of HRG in this pathway, together with the ability of HRG to inhibit hemolysis under septic conditions. HRG supplementation might be a novel therapeutic strategy for inflammatory disorders, especially sepsis.

Ferric Citrate Supplementation Reduces Red-Blood-Cell Aggregation and Improves CD163+ Macrophage-Mediated Hemoglobin Metabolism in a Rat Model of High-Fat-Diet-Induced Obesity.

SCOPE: In adults, >90% of the daily iron requirement is derived from macrophage-mediated heme iron, recycling from senescent red blood cells (RBCs) or free hemoglobin (Hb). Currently, the effects of pharmacological doses of iron supplementation on RBCs and heme iron recycling in obesity are unclear. METHODS AND RESULTS: Sprague Dawley rats are fed a standard diet or a 50% high-fat diet (HFD) with (0.25, 1, and 2 g of ferric iron per kg diet) or without ferric citrate supplementation for 12 weeks. Ferric iron increases hepatic iron accumulation in macrophages and hepatocyte-like cells. Compared with rats that received the standard diet, HFD-fed rats exhibit higher RBC aggregation and serum-free Hb levels but lower LVV-hemorphin-7 levels. These effects are reversed by ferric citrate supplementation. Immunofluorescent staining reveals that ferric iron increases the expression of hepatic CD163+ macrophages and heme oxygenase (HO)-1. A further analysis reveals the dose-related effects of ferric iron on hepatic globin degradation proteins (cathepsin D and glyoxalase 1), cytochrome p450 reductase expression, and HO-1 enzyme activity. CONCLUSIONS: Ferric citrate supplementation reduces RBC aggregation and improves CD163+ macrophage-mediated Hb metabolism in HFD-induced obese rats. These findings suggest that ferric citrate may be explored as an alternative treatment method for RBC dysfunction.

Hemorheological effects of secoisolariciresinol in ovariectomized rats.

BACKGROUND: Postmenopausal women often develop hemorheological disorders which may affect the systemic blood circulation and present a cardiovascular risk factor. OBJECTIVE: We evaluated effects of secoisolariciresinol (SECO), a phytoestrogen, on hemorheological parameters and lipid peroxidation in a model of the age-related and/or surgical menopause induced by ovariectomy in rats. METHODS: Arterial blood was sampled from sham-operated female rats, ovariectomized rats (OVX), and OVX treated with SECO (OVXSECO) (20 mg/kg/day intragastrically for two weeks). Plasma estrogen concentration and the following hemorheological parameters were measured: RBC aggregation (half-time of aggregation, T1/2; amplitude of aggregation, AMP; aggregation index, AI), RBC deformability (elongation index, EI), whole blood viscosity at the shear rate of 3-300 s-1, plasma viscosity, hematocrit, plasma fibrinogen. Lipid peroxidation was evaluated by measuring conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS) in plasma. RESULTS: Ovariectomy in rats caused a 60% decrease in plasma estrogen level and triggered the development of macro- and microhemorheological abnormalities. Blood viscosity increased by 12-31%, RBC elongation index reduced by 16-28%, and T1/2 and AI increased by 35% and 29% respectively. The increase in blood viscosity correlated predominantly with reduced RBC deformability. Plasma CD and TBARS were elevated by 47% and 104% respectively. SECO therapy for OVX rats reduced blood viscosity by 9-18% and T1/2 by 32%, and increased EI by 4-17%. SECO therapy disrupted the correlation between blood viscosity and RBC deformability. Lipid peroxidation was significantly inhibited, as shown by the reduction in CD and TBARS plasma concentrations by 89% and 70% respectively. SECO did not affect plasma viscosity, estrogen or fibrinogen levels. CONCLUSIONS: SECO treatment for OVX rats improves blood macro- and microrheological parameters, possibly through antioxidant protection of RBC.

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.

Derivation of Cinnamon Blocks Leukocyte Attachment by Interacting with Sialosides.

Molecules derived from cinnamon have demonstrated diverse pharmacological activities against infectious pathogens, diabetes and inflammatory diseases. This study aims to evaluate the effect of the cinnamon-derived molecule IND02 on the adhesion of leukocytes to host cells. The anti-inflammatory ability of IND02, a pentameric procyanidin type A polyphenol polymer isolated from cinnamon alcohol extract, was examined. Pretreatment with IND02 significantly reduced the attachment of THP-1 cells or neutrophils to TNF-α-activated HUVECs or E-selectin/ICAM-1, respectively. IND02 also reduced the binding of E-, L- and P-selectins with sialosides. Furthermore, IND02 could agglutinate human red blood cells (RBC), and the agglutination could be disrupted by sialylated glycoprotein. Our findings demonstrate that IND02, a cinnamon-derived compound, can interact with sialosides and block the binding of selectins and leukocytes with sialic acids.

[THE ROLE OF NITRIC OXIDE AND BLOOD RHEOLOGICAL PROPERTIES IN THE MAINTENANCE OF A TEMPERATURE HOMEOSTASIS IN THE BRAIN TISSUE].

The problem of temperature regulation in the brain tissue in conditions of whole body hyperthermia was investigated in experiments on white rats. The received results revealed that the brain is provided with a highly efficient system for temperature autoregulation against the changes in environmental temperature. According to our data the upper limit of this autoregulation (for rats, at least) is about the 450C of environmental temperature. The important role in functioning of this autoregulatory system belongs to Nitric Oxide. It is revealed also that the increase in the index of red cells aggregability may significantly hinder (among other things) maintaining of the temperature homeostasis in the brain.

Core bioactive components promoting blood circulation in the traditional Chinese medicine compound xueshuantong capsule (CXC) based on the relevance analysis between chemical HPLC fingerprint and in vivo biological effects.

Compound xueshuantong capsule (CXC) is an oral traditional Chinese herbal formula (CHF) comprised of Panax notoginseng (PN), Radix astragali (RA), Salvia miltiorrhizae (SM), and Radix scrophulariaceae (RS). The present investigation was designed to explore the core bioactive components promoting blood circulation in CXC using high-performance liquid chromatography (HPLC) and animal studies. CXC samples were prepared with different proportions of the 4 herbs according to a four-factor, nine-level uniform design. CXC samples were assessed with HPLC, which identified 21 components. For the animal experiments, rats were soaked in ice water during the time interval between two adrenaline hydrochloride injections to reduce blood circulation. We assessed whole-blood viscosity (WBV), erythrocyte aggregation and red corpuscle electrophoresis indices (EAI and RCEI, respectively), plasma viscosity (PV), maximum platelet aggregation rate (MPAR), activated partial thromboplastin time (APTT), and prothrombin time (PT). Based on the hypothesis that CXC sample effects varied with differences in components, we performed grey relational analysis (GRA), principal component analysis (PCA), ridge regression (RR), and radial basis function (RBF) to evaluate the contribution of each identified component. Our results indicate that panaxytriol, ginsenoside Rb1, angoroside C, protocatechualdehyde, ginsenoside Rd, and calycosin-7-O-ß-D-glucoside are the core bioactive components, and that they might play different roles in the alleviation of circulation dysfunction. Panaxytriol and ginsenoside Rb1 had close relevance to red blood cell (RBC) aggregation, angoroside C was related to platelet aggregation, protocatechualdehyde was involved in intrinsic clotting activity, ginsenoside Rd affected RBC deformability and plasma proteins, and calycosin-7-O-ß-D-glucoside influenced extrinsic clotting activity. This study indicates that angoroside C, calycosin-7-O-ß-D-glucoside, panaxytriol, and protocatechualdehyde may have novel therapeutic uses.

Effects of nickel chloride on the erythrocytes and erythrocyte immune adherence function in broilers.

This study was conducted to investigate the immune adherence function of erythrocytes and erythrocyte induced by dietary nickel chloride (NiCl2) in broilers fed on a control diet and three experimental diets supplemented with 300, 600, and 900 mg/kg NiCl2 for 42 days. Blood samples were collected from five broilers in each group at 14, 28, and 42 days of age. Changes of erythrocyte parameters showed that total erythrocyte count (TEC), hemoglobin (Hb) contents, and packed cell volume (PCV) were significantly lower (p < 0.05 or p < 0.01) and erythrocyte osmotic fragility (EOF) was higher (p < 0.05 or p < 0.01) in the 600 and 900 mg/kg groups at 28 and 42 days of age than those in the control group, and the sodium-potassium adenosine triphosphatase (Na(+)/K(+)-ATPase) and calcium adenosine triphosphatase (Ca(2+)-ATPase) activities were significantly decreased (p < 0.05 or p < 0.01) in the NiCl2-treated groups. The results of erythrocyte immune adherence function indicated that erythrocyte C3b receptor rosette rate (E-C3bRR) was significantly decreased (p < 0.05 or p < 0.01) in the 600 and 900 mg/kg groups and in the 300 mg/kg group at 42 days of age, whereas the erythrocyte immune complex rosette rate (E-ICRR) was markedly increased (p < 0.05 or p < 0.01) in the 300, 600, and 900 mg/kg groups at 28 and 42 days of age. It was concluded that dietary NiCl2 in excess of 300 mg/kg caused anemia and impaired the erythrocytic integrity, erythrocytic ability to transport oxygen, and erythrocyte immune adherence function in broilers. Impairment of the erythrocytes and erythrocyte immune adherence function was one of main effect mechanisms of NiCl2 on the blood function.

Effect of Morinda citrifolia fruit extract and its iridoid glycosides on blood fluidity.

The aim of this study was to investigate the effect of Morinda citrifolia fruit on blood fluidity. M. citrifolia fruit extract (MCF-ext) was investigated for its influence on blood aggregation and fibrinolysis. MCF-ext inhibited polybrene-induced erythrocyte aggregation and thrombin activity. The fibrinolytic activity of MCF-ext, in the euglobulin lysis time test and fibrin plate assay, is reported here for the first time. One of the active compounds was an iridoid glycoside, asperulosidic acid. The results indicated that MCF-ext is a potentially useful health food which is capable of improving blood flow and preventing lifestyle-related diseases.

Zn(II)-curcumin protects against hemorheological alterations, oxidative stress and liver injury in a rat model of acute alcoholism.

Curcumin can chelate metal ions, forming metallocomplexes. We compared the effects of Zn(II)-curcumin with curcumin against hemorheological alterations, oxidative stress and liver injury in a rat model of acute alcoholism. Oral administration of Zn(II)-curcumin dose-dependently prevented the ethanol-induced elevation of serum malondialdehyde (MDA) content and reductions in glutathione level and superoxide dismutase (SOD) activity. Zn(II)-curcumin also inhibited ethanol-induced liver injury. Additionally, Zn(II)-curcumin dose-dependently inhibited hemorheological abnormalities, including the ethanol-induced elevation of whole blood viscosity, plasma viscosity, blood viscosity at corrected hematocrit (45%), erythrocyte aggregation index, erythrocyte rigidity index and hematocrit. Compared to curcumin at the same dose, Zn(II)-curcumin more effectively elevated SOD activity, ameliorated liver injury and improved hemorheological variables. These results suggest that Zn(II)-curcumin protected the rats from ethanol-induced liver injury and hemorheological abnormalities via the synergistic effect of curcumin and zinc.

Hemorheological effects of complex isoflavonoid preparation in ovariectomized rats.

We have shown that rats with simulated hormone deficiency develop the hyperviscosity syndrome. Course intragastric administration (14 days) of the composition of extracts from red clover (100 mg/kg) and alfalfa (100 mg/kg) prevents the development of hyperviscosity syndrome in rats with hormone deficiency.

Measuring red blood cell aggregation forces using double optical tweezers.

Classic immunohematology approaches, based on agglutination techniques, have been used in manual and automated immunohematology laboratory routines. Red blood cell (RBC) agglutination depends on intermolecular attractive forces (hydrophobic bonds, Van der Walls, electrostatic forces and hydrogen bonds) and repulsive interactions (zeta potential). The aim of this study was to measure the force involved in RBC aggregation using double optical tweezers, in normal serum, in the presence of erythrocyte antibodies and associated to agglutination potentiator solutions (Dextran, low ionic strength solution [LISS] and enzymes). The optical tweezers consisted of a neodymium:yattrium aluminium garnet (Nd:YAG) laser beam focused through a microscope equipped with a minicam, which registered the trapped cell image in a computer where they could be analyzed using a software. For measuring RBC aggregation, a silica bead attached to RBCs was trapped and the force needed to slide one RBC over the other, as a function of the velocities, was determined. The median of the RBC aggregation force measured in normal serum (control) was 1 × 10(-3) (0.1-2.5) poise.cm. The samples analyzed with anti-D showed 2 × 10(-3) (1.0-4.0) poise.cm (p < 0.001). RBC diluted in potentiator solutions (Dextran 0.15%, Bromelain and LISS) in the absence of erythrocyte antibodies, did not present agglutination. High adherence was observed when RBCs were treated with papain. Results are in agreement with the imunohematological routine, in which non-specific results are not observed when using LISS, Dextran and Bromelain. Nevertheless, false positive results are frequently observed in manual and automated microplate analyzer using papain enzyme. The methodology proposed is simple and could provide specific information with the possibility of meansuration regarding RBC interaction.

Magnetic and degradable polymer/bioactive glass composite nanoparticles for biomedical applications.

The present study focuses on the development of a biocompatible and biodegradable iron oxide incorporated chitosan-gelatin bioglass composite nanoparticles [Fe-BG]. The developed composite nanoparticle was analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermo gravimetric analysis (TG) and differential scanning calorimetry analysis (DSC). The size of the negatively charged composite nanoparticle was in the range of 43-51 nm. The in vitro analysis of the composite nanoparticles was carried out by cell aggregation, protein adsorption and haemolytic activity. The magnetic hysteresis value of the composite nanoparticle showed that it is a soft magnetic material. The presence of iron oxide in the chitosan-gelatin bioglass [BG] matrix enhances biodegradability as indicated in the TG studies. Iron-oxide in equal amount to bioglass in the polymer matrix has been obtained as the optimized system. The developed composite nanoparticle is a soft magnetic material and is suitable for the magnetic hyperthermia treatment and drug delivery. More detailed in vivo studies are needed to confirm the biodegradation profile and biological activity of the material.

[Effects of the effective components group of xiaoshuantongluo formula on rat acute blood stasis model].

Effects of the effective components group of Xiaoshuantongluo formula (XECG) on rat acute blood stasis model were studied under the guidance of the concept of effective components group. Rat acute blood stasis model was induced by subcutaneous injection of epinephrine combined with ice water bath. Hemorheology indices such as whole blood viscosity, plasma viscosity, erythrocyte aggregation index and platelet aggregation rate; coagulation parameters including PT, APTT, TT and FIB; 6-keto-PGF1alpha, TXB2 and D-dimer levels were determined to evaluate the effects of XECG. The results showed that XECG significantly reduced ADP-induced platelet aggregation, but showed little influence on the whole blood viscosity, plasma viscosity and erythrocyte aggregation rate. XECG extended PT and TT slightly, but had no effects on APTT and FIB content. D-dimer levels significantly decreased after administration of XECG with a little decrease of TXB2, but the content of 6-keto-PGF1alpha did not change significantly. The results suggest that the role of XECG of anti-aggregation is more prominent.

[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).