Rat Erythrocyte Membrane Research Articles

EKSTRAK ETANOL DAUN KERSEN (Muntingia calabura) MENINGKATKAN KETAHANAN MEMBRAN ERITROSIT TIKUS YANG DIPERLAKUKAN DIABETES MELLITUS

The condition of Diabetes Mellitus (DM) due to hyperglycaemia can induce free radicals and decreased oxidant defence system, chronic hyperglycaemia will result in increased production of free radicals resulting in oxidative stress. The aim of this study was determine the oxidant activity of Kersen Leaf Extract in increasing the resistance of erythrocyte membranes in rats treated with diabetes mellitus by measuring the activity of Malondialdehyde (MDA) and measuring the percentage of erythrocyte cells that are hemolyzed. This study was conducted in vivo by examining the antioxidant activity of Muntingia calabura L. by measuring the levels of MDA and membrane resistance in diabetic rats. This study used animal model Rattus Norvegicus Wistar strain, total of 30 rats was divided into six groups with 5 rats in each group, which are negative control group, positive control group, positive control was added standard drug group, and diabetic rats. Kersen (Muntingia calabura L.) leaves extract reduced Malondialdehyde (MDA) levels of erythrocytes in diabetic rats at an optimum dose of 400 mg/kg of weight per day with a mean MDA value of 4.91 ± 2.1 µmol/ml. In addition, can reduce the amount of hemolysis of erythrocytes in diabetic rats at an optimum dose of 400 mg/kg of weight per day, and can reduce the number of abnormal erythrocytes in rats treated with diabetes mellitus with an optimum dose of 400 mg/kg bw/day with a mean haemolysis value of 33.34 ± 4.04%. Kersen (Muntingia calabura L) leaf extract increases the resistance of erythrocyte of diabetic rat’s.

Impact of Ethanolic Extract of Dissotis rotundifolia Leaves on Wistar Rat Erythrocyte Membrane

Medicinal plants have been shown to affect the stability of the erythrocyte membrane. Dissotis rotundifolia leaves have been used in Nigeria to treat certain diseased conditions not minding the effect on the erythrocyte membrane. The aimed of this work is to investigate the impact ethanolic extract of Dissotis rotundifolia leaves have on wistar rat erythrocyte membrane. Twenty-five adult wistar albino rats were randomly distributed into five groups administered 0 (control), 50, 100, 150 and 200 mg/100 g body weight. Erythrocytes osmotic fragility was determined by measuring the release of haemoglobin from blood added to tubes containing serially diluted phosphate buffered saline (PBS, pH 7.4). The results of mean corpuscular fragility (MCF) showed non-significant (p > 0.05) decrease for 50 and 100 mg/100 g body weight doses, while 150 and 200 mg/100 g body weight doses showed non-significant (p > 0.05) increase. The erythrocytes were stabilized by 50, 100 and 150 mg/100 g body weight, while 200 mg/100 g body weight destabilized the erythrocyte membrane. Also, 200 mg/100 g body weight dose showed significant (p ≤ 0.05) increase in malondialdehyde (MDA) levels. At relatively high doses, Dissotis rotundifolia may induce oxidative stress causing significant levels of MDA production resulting in alteration of the chemical and structural composition of the membrane. In conclusion Dissotis rotundifolia at low doses may be useful in maintaining the erythrocyte by stabilizing the membrane, whereas high doses destabilize the membrane and compromise membrane integrity.

Balanites aegyptiaca (Heglig Dates) Reduces Oxidative Stress and Biophysical Alterations of Erythrocyte Membranes in Streptozotocin-Induced Diabetic Rats

Balanites aegyptiaca (Heglig Dates) Reduces Oxidative Stress and Biophysical Alterations of Erythrocyte Membranes in Streptozotocin-Induced Diabetic Rats

Comparative study of technologies for extraction of biologically active substances from the raw material of animal origin

Technologies of isolation and concentration of biologically active substances, developed in the middle of the 20th century, need adjustment and adaptation to modern conditions both to increase the activity of substances and for greater economic efficiency. The aim of the research is the comparison of dynamics of biologically active compounds extraction from porcines pancreas in two methods: the saline method based on 0.9% sodium chloride solution, and the acidic method based on 2.4% trichloroacetic acid solution. Also the purpose of research is to assess the possibilities for further optimization of technologies. The total protein concentration based on the biuret reaction in the samples taken during the extraction, as well as the calculation and analysis of the point degrees and rates of extraction are chosen as the controlled parameters. Local maxima of the protein yields into the extractant media at the 60th, 135th and 255th minute were recorded during saline extraction; and at the 75th and 135th minute during acid extraction. Also the proteomic profile of the extracts was studied. Wide range of compounds with molecular weight of less than 52 kDa was found in extracts based on physiological saline solution, and protein substances of whole presented range of molecular weights in trichloroacetic acid based extracts were considered. The predominance of low molecular weight protein fraction of interest was noted also in this method of extraction in comparison with the other methods of extraction. According to the UniProt database, we assume availability of probable compounds with a molecular weight of less than 30 kDa in the purified acidic extract. The presence of some proteins absent in the final saline extract was noted. The acidic erythrograms showed a weak degrading effect of both types of extracts on the membranes of rat erythrocytes, as well as the cytoprotective effect of acidic ultrafiltrates (less than 3 kDa). The obtained results prove a better efficiency of trichloroacetic acid extraction method used for obtaining a mixture of a wide range of compounds, including biologically active substances of low molecular weight.

Protective effect of Terminalia arjuna against alcohol induced oxidative damage of rat erythrocyte membranes

BackgroundAlcohol is a widely abused drug with many health implications, mainly caused by the oxidative and nitrosative stress on different body parts. Ayurvedic herbalism authenticates the multiple therapeutic applications of Terminalia arjuna bark due to its rich phytochemical repertoire. ObjectiveTo observe the extent of oxidative damage caused to erythrocytes by alcohol and assess the protective ability of T. arjuna bark powder aqueous extract (AETA) against the damage. Materials and methodsWister albino rats were categorized into four groups of eight rats per group; first group (control) was fed with glucose, second group was given alcohol at a dose of 20% v/v; 5g alcohol/kg b. wt/day, third group was co-administered with AETA (0.5 g/kg b. wt/day) and alcohol and the fourth group was kept on bark extract alone. Blood samples were collected and evaluated for different biochemical parameters after the completion of the treatment period. ResultsAlcohol significantly increased the erythrocyte membrane protein carbonyl and malondialdehyde (MDA) contents, along with a concomitant decrease in the membrane antioxidant status, when compared to the control group. Chromatographic analysis of the alcohol-treated rat erythrocyte membranes revealed altered membrane individual phospholipid contents and fluidity properties. Alcohol-induced morphological changes in the erythrocytes and its effect on decreasing the resistance of hypotonic shock induced by NaCl are evident from the hemolysis curves. However, AETA administration to alcoholic rats beneficially modulated the membrane properties anvd protected erythrocytes from damage. ConclusionResults suggest that AETA protects erythrocytes from alcohol-induced oxidative stress, biophysical, and biochemical changes very effectively.

Proteomics analysis of erythrocyte membrane in rats with high altitude polycythemia before and after intervention with salidroside

To investigate the effect of salidroside on the proteomics of erythrocyte membrane in high altitude erythrocytosis(HAPC) rats, in order to explore the mechanism of salidroside in improving HAPC based on the proteomics analysis. First, HPAC rat models were established, and 16 rats were randomly divided into HAPC model group and salidroside(100 mg·kg~(-1)) treatment group(8 rats per group). Saline was administered to the HAPC model group, while salidroside treatment group was given 100 mg·kg~(-1) salidroside once a day. After continuous oral administration with salidroside for 40 days(once a day), blood was collected from the femoral artery to obtain total red blood cell membrane proteins. Two-dimensional electrophoresis was used to separate total proteins. The two-dimensional electrophoresis of erythrocyte membrane proteins was analyzed before and after salidroside intervention, and the proteins with significant differences were identified by mass spectrometry. Finally, biological functions were analyzed using bioinformatics. A two-dimensional electrophoresis method was used to establish a protein expression profile with a high resolution and reproducibility of erythrocyte membranes in HAPC rats. Salidroside treatment significantly changed 18 protein spots in the 2-DE map of erythrocyte membranes, of which 13 proteins were up-regulated and 5 proteins were down-regulated. Eight differential proteins were successfully identified by mass spectrometry. Moreover, bioinformatics analysis found that these differential proteins were involved in such biological processes as oxidative stress, redox, and peroxisome pathway, which are mainly associated with peroxisome and MAPK signaling pathways. Therefore, salidroside could significantly change the expressions of erythrocyte membrane proteins in HAPC rats. Eight differential proteins were identified by a proteomic-based approach. The differential proteins were involved in such biological processes as oxidative stress, redox, peroxisome pathway.

Effect of hydro-methanol stem bark extract of Burkea africana on erythrocyte osmotic fragility and haematological parameters in acetaminophen-poisoned rats

BackgroundBurkea africana is a widely used medicinal plant in folkloric medicine in many developing countries of the world. It is useful in the treatment of various ailments including hepatitis, jaundice, diarrhea, stomach aches, abscesses, oedema, epilepsy, bloody diarrhea, gonorrhea, syphilis, toothaches and poisoning. Nevertheless, there are little or no scientific evidence to substantiate this medicinal claim by traditional healers. Burkea africana stem bark was therefore, investigated for its protective or stabilizing effect on erythrocyte membrane in acetaminophen-treated rats. B. africana stem bark was extracted using 80% methanol. Erythrocyte stabilizing effect was studied using erythrocyte osmotic fragility (EOF) test. Thirty (30) male rats were randomly assigned into five (5) groups of six (6) rats each. Groups 1 and 2 served as normal control and negative control (acetaminophen-treated group) respectively. Groups 3, 4 and 5 were pretreated with methanol stem bark extract of Burkea africana (MSBEBA) at doses of 200, 400 and 600 mg/kg body weight respectively once daily for seven (7) days. Blood samples were collected from the animals in all the groups on the 8 day for evaluation of packed cell volume, haemoglobin, red blood cell, white blood cell counts, and differential white blood cell count as well as erythrocyte osmotic fragility.ResultsThe erythrocyte osmotic fragility test showed that there was a significantly (p < 0.05) low percentage hemolysis in the groups pre-treated with the extract when compared with the negative control. The percentage hemolysis was least at 600 mg/kg body weight of the extract. There was also a significant (p < 0.05) increase in the packed cell volume, haemoglobin, red blood cell count at all the doses of the extract used. Neutrophils were significantly (p < 0.05) decreased while lymphocytes were significantly increased in the groups administered MSBEBA 400 and 600 mg/kg body weight.ConclusionMethanol stem bark extract of Burkea africana had protective effect on the red blood cells and also improved haematological parameters. This indicates that Burkea africana may be useful in the treatment of disease conditions that results in hemolytic anemia by stabilizing red erythrocyte membranes and enhancing erythropoiesis.

Induced alteration of rat erythrocyte membrane with effect of pyrethroid based compounds.

The effects of tetramethrin and prallethrin exposure on plasma total proteins, free amino acids, albumins, urea, urea nitrogen, uric acid, creatinine were tested. Serum SGOT, SGPT and lipid profile, antioxidants super oxide dismutase (SOD), catalase, GSH, G-Px, phospholipids, cholesterol, C/P ratio in membranes of erythrocyte and membrane fluidity were analyzed. The reason of the study were analyzed to examine the possessions of mosquito repellent pyrethroid (MRP) based compounds tetramethrin and prallethrin exposure on plasma profile, antioxidant status of erythrocyte membrane, membrane fluidity in male Wistar rats. We tested chronically for three months exposure every day (continuously for 8–10 h per day by inhalation) of tetramethrin and prallethrin markedly available (MRP) repellents treated on male Wistar rats. Our results confirmed that tetrarmethrin and prallethrin treatment effect of plasma profile alterations, and lipid homeostasis mechanism in Red Blood cells (RBCs). Tetramethrin and prallethrin treatment significantly increased in erythrocyte membrane phospholipids and decreased levels of cholesterol with no change of protein content, increased C/P ration levels. Inhalation of tetramethrin and prallethrin stimulate plasma biophysical and biochemical modify SGOT, SGPT, erythrocyte membrane cholesterol and phospholipid levels, individual phospholipids and membrane fluidity of exposure rats compared to controls.

Erythroleukemia treated effects of rat plasma profile and erythrocyte membranes.

Erythroleukemia disease is caused by over production of malignant blood and immature large number of blood cells enters into peripheral compartment. Biophysical and biochemical changes in plasma and erythrocyte membrane in erythroleukemia treated rats were identified. Our study, leukemia is experimentally exposed in rats were injecting erythroleukemia cells (FLC) (H-2d) intravenously in adult rats and normal control rats were maintained. Significant increase in the activity of blood glucose, proteins levels, aspartate transaminase (AST) and alanine transaminase (ALT) values and significant decrease in haemoglobin (Hb), albumin levels in erythroleukemia treated rats were observed when compared with control rats. Cholesterol and low density liproprotein (LDL) levels increased significantly in erythroleukemia treated rats but triglycerides, high density lipoprotein (HDL) and very low density lipoprotein (VLDL) levels decreased significantly. Levels of red cell membrane cholesterol decreased in erythroleukemia treated rats in comparison with control while levels of phospholipids and proteins increased in erythrocytes of erythroleukemia treated rats. Red blood cell (RBC) and white blood cell (WBC) counts increased significantly and platelet count decreased. C/P (cholesterol/phospholipid) ratio decreased significantly in erythroleukemia treated rats. This study has been undertaken for the first time to investigate the effect of (FLC) (H-2d) erythroleukemia cells (treated) in intravenously in adult rats and normal control rats. Results indicate biophysical and biochemical alterations at molecular level in plasma and erythrocyte membrane.

Study of cytotoxicity performance of carbon nanohorns by method of spin probes

The effects of as-produced and treated by HNO3(3M) carbon nanohorns on the microviscosity of rat erythrocyte membranes and the viscosity of the water-containing plasma protein matrix were investigated by the method of spin probes. Addition of nanohorns at the concentration of 100 μg/ml to a suspension of erythrocytes led to an increase in membrane microviscosity during 4 h (about 60% effect). In addition, it was shown that nanohorns also induced an increased polarity of the microenvironment for lipophilic probes in the outer layer of membrane phospholipids, as well as disorders in erythrocytes membranes. Addition of nanohorns to plasma led to a little decrease in the viscosity of water and protein matrix, apparently, due to its partial destruction, impacting especially albumin. Pristine and treated by HNO3(3M) acid nanohorns was found more cytotoxic than nanoparticles of oxidized graphene, and significantly less than carbon nanotubes, which are known to dramatically increase the microviscosity of the membranes of erythrocytes and disrupt their integrity.

Acute Toxicity and Erythrocyte Osmotic Fragility Studies of Methanol Leaf Extract of Asystasia vogeliana in Rats

Aim: To investigate the phytoconstituents of methanol and petroleum leaf extracts of Asystasia vogeliana (MLEAV and PLEAV), the median lethal dose (LD50) and the effects of MLEAV on body weight, organosomatic indices in vital organs and erythrocyte membrane of Albino Wistar rats during sub-acute administration.&#x0D; Place and Duration of Study: Department of Veterinary Physiology and Pharmacology, University of Nigeria, Nsukka, in 2017.&#x0D; Methodology: The crude extracts of MLEAV and PLEAV were used in determining the qualitative and quantitative analyses. The rats were assigned into four groups and dosed orally with distilled water (0.5 ml/100 g) as Group I, 62.5 mg/kg MLEAV (Group II), 125 mg/kg MLEAV (Group III) and 250 mg/kg MLEAV (Group IV) once daily for 28 days. Blood samples were collected from all the rats via the medial canthus into EDTA bottles for erythrocyte osmotic fragility (EOF) study on day 29. Relative organ-body weight indices of vital organs (spleen, heart, liver and kidney) were also evaluated.&#x0D; Results: MLEAV and PLEAV showed the presence of saponins, flavonoids, phenols, alkaloids, anthraquinones and steroids. The total phenolic contents of MLEAV (3704.30 ± 44.00) significantly increase (P = 0.000) when compared with PLEAV (1349.46 ± 35.25). The LD50 of MLEAV is above 5000 mg/kg. There were significant (P &lt; 0.05) decreases in the body weights of rats in Groups III and IV from 3rd to 4th week when compared with their baseline weights. There were significant (P &lt; 0.05) increases in the relative spleen-body weight in Group IV when compared with other groups. There was no significant change (P &gt; 0.05) in the hemolysis of rats in Group II when compared with the control group at 0.9% NaCl concentration.&#x0D; Conclusions: The findings reveal that MLEAV showed better antioxidant capacity than PLEAV, and that 62.5 mg/kg of MLEAV is safe during the sub-acute administration.

Effects of hypertension and FAAH inhibitor treatment of rats with primary and secondary hypertension considering the physicochemical properties of erythrocytes

Hypertension is one of the most common cardiovascular diseases in the world and is associated with oxidative stress. The aim of this study was to examine the effect of the chronic administration of the fatty-acid amide hydrolase inhibitor (URB597-[3-(3-carbamoylphenyl)phenyl]N-cyclohexylcarbamate) to rats with primary (SHRs – spontaneously hypertensive rats) and secondary (DOCA-salt – 11-desoxycorticosterone acetate-salt-induced hypertension) hypertension on the composition and physicochemical properties of erythrocytes membrane. Because changes in membrane composition lead to modifications of electrical charge what may affect cell functions, the levels of following components were determined: four classes of membrane phospholipids (by HPLC – high-performance liquid chromatograph), sialic acid (by resorcinol method), lipid peroxidation product – malondialdehyde (by GCMS – gas chromatography-mass spectrometry). The reduced levels of phospholipids and sialic acid, as well as the increased levels of malonodialdehyde observed in the erythrocyte membrane of rats with primary and secondary hypertension led to a decrease in the negative electrical charge of the membrane. Long-term administration of URB597 to SHRs and DOCA-salt-treated rats partially prevented changes caused by hypertension. Using theoretical equations and the dependence of cell surface charge density as a function of pH, total surface concentrations of acid and base groups and their association constants have been determined. Considering the changes in physicochemical parameters of erythrocyte membranes, URB597 can be considered a potential protective factor for erythrocytes in situations of metabolic changes associated with oxidative stress.

In Russian

The microviscosity of erythrocyte membranes is directly related to their integrity, the violation of which in the presence of foreign objects manifests itself in a sharp increase in the microviscosity index, which certainly indicates the degree of cytotoxic effect of objects in contact with cells of a living organism. Using the spin probe method, a comparative study was made of the effect of a number of carbon nanoparticles on the microviscosity of rat erythrocyte membranes. It has been found that the presence of oxidized graphene (OG) in suspension of red blood cells practically does not affect the microviscosity index of membranes. In the presence of carbon nanotubes (CNTs) of various structures during prolonged (24 h) incubation with erythrocytes, an increase in the microviscosity of erythrocyte membranes is 1.5–2 times. Oxidized multi-walled nanotubes exert the greatest effect. Hydrophobic multi-walled CNTs have a smaller effect, and single-walled nanotubes are characterized by a slight effect on the membranes. Incubation of erythrocytes with carbon nanochorns (CNCh) leads to a significant increase in the microviscosity of erythrocyte membranes by 60 % and higher; after 1 h of incubation, the polarity of the surface of the lipid layer of the membranes increases stepwise, apparently due to the destruction of the membrane and the ingress of water molecules there, as well as the disorder of phospholipids. The introduction of detonation nanodiamond (DND) nanoparticles into a suspension of erythrocytes at a concentration of 25 μg/ml produced no noticeable change in the membrane microviscosity index. An increase in the concentration of DND in suspension of red blood cells to 50 and 75 μg/ml led to a decrease in the microviscosity of erythrocyte membranes (increase in fluidity of the membranes) by 20 and 28 %, respectively. Thus, among carbon nanoparticles, nanotubes and nanochorns can exhibit cytotoxicity, which is mainly due to their structure, size, and shape.

In Russian

The method of spin probes investigated the effect of various concentrations of detonation nanodiamonds (DND) 25, 50 and 75 µg/ml on the microviscosity of rat erythrocyte membranes. For this, a lipophilic spin probe based on palmetic acid was introduced into the erythrocyte membrane. The introduction of DND into a suspension of erythrocytes at a concentration of 25 μg/ml did not lead to any changes in the microviscosity of erythrocyte membranes within the experimental error. At the same time, an increase in the concentration of DND in suspension of erythrocytes to 50 and 75 µg/ml resulted in to a marked decrease in the microviscosity of erythrocyte membranes (increase in membrane fluidity) by 20 and 28 %, respectively. A noticeable decrease in the intensity of the EPR spectrum after 4 h of incubation of erythrocytes with DNA (50 µg/ml) indicates the antioxidant activity of nanodiamond — the ability to be an electron donor and restore the nitroxyl stable radical (spin probe) to hydroxylamine. Physiologically, an increase in erythrocyte membrane turnover is of great importance for the organism, since allows red blood cells to better penetrate thin or narrowed capillaries and more efficiently nourish the tissues and organs of the body with oxygen. In addition, an increase in cell membrane fluidity increases the activity of membrane enzymes, which should lead to activation of metabolic and regulatory processes in cells and in the body as a whole. Perhaps this may explain the successful use of DND in oncology, treatment of the gastrointestinal tract, etc. At the same time, an excessive increase in the fluidity of cell membranes at high concentrations of DND can lead to irreversible changes in the native structure of cell membranes.

LIPID COMPOSITION AND MEMBRANOPROTECTIVE ACTION OF EXTRACT FROM MARINE GREEN ALGAE ULVA LACTUCA (L.)

The object of the present study was a water-alcohol extract obtained from the dried thallus of the marine green alga Ulva lactuca (L.) (syn.: Ulva fenestrate P. et R.) – ulva lettuce. Glycolipids (40.6%) and neutral lipids (34%) prevailed in the lipid fraction of the extract; phospholipids contained 13.4% of the total lipids. The content of polyunsaturated fatty acids (PUFA) was 50% of the total amount of fatty acids, among which PUFA of the n-3 family predominated (37.43%). On the model of toxic hepatitis induced by the introduction of carbon tetrachloride (CCl4) (50% solution in olive oil, subcutaneously 2 ml/kg for 4 days), we study the effect of the lipid fraction of U. lactuca extract and the commercial reference preparation Essentiale® on the physiological and biochemical characteristics of erythrocytes and lipid composition of erythrocyte membranes in rats. The introduction of the lipid fraction from the ulva (dose 80 mg of total lipids per kg of body weight) to the animals intragastrically for 7 days after withdrawal of CCl4 exerted a protective effect, which was manifested in the restoration of the erythrocyte size characteristics (average volume and diameter), their osmotic resistance to hemolysis, levels of malondialdehyde and reduced glutathione, as well as maintaining of the ratio of phospholipid fractions. Under the damaging effects of CCl4, the lipid fraction from the green alga U. lactuca was not inferior to the effectiveness of reference preparation Essentiale® in restoring of the physiological characteristics of erythrocytes and the phospholipid composition of its membranes.

In Russian

in Russian

Whey protein concentrate supplementation protects erythrocyte membrane from aging‐induced alterations in rats

Whey protein concentrate (WPC), a protein complex derived from milk, exerts a number of health benefits. The present study deals with the beneficial effects of WPC on erythrocyte membrane in rats during aging. Male Wistar rats of two different age groups: young (4 months) and old (24 months) were supplemented with WPC (300 mg/kg b.w. orally) for 28 days. The effect of WPC on age-dependent activities of membrane transporters: Na+/K+-ATPase, Ca2+ATPase (PMCA), and Na+/H+ Exchanger, and also on markers of oxidative stress: protein carbonyl, lipid hydroperoxides, sialic acid, and total thiol was determined. WPC supplementation ameliorated the age-dependent alteration in the activity of membrane-bound transporters, and biomarkers of oxidative stress in old-aged rats. Thus, WPC could be a useful dietary regimen and may augment the ability of cells to fight damage against age-dependent structural and functional alterations. Practical applications Anti-aging strategies focused on nutritional modulation of health span provide an exciting area of research. Whey protein, a vital constituent of milk is rich in sulfur-containing amino acids and has been widely accepted as an effective and safe cysteine donor for glutathione replenishment. It is acknowledged that biomarkers of oxidative stress provide a useful indicator for assessing age-dependent alterations. Nutritional supplements which augment redox balance provide an effective intervention strategy for age-dependent oxidative damage. In this study, we provide experimental evidence of WPC-induced protective effect on biomarkers of aging in rats. Based on the studies on rats, we hypothesize that similar effect may be obtained in humans. Thus, WPC could be explored as a functional food to boost the cellular antioxidant levels and improve health span in humans.

The Fluorescent Probe Method in Investigation of the State of Erythrocyte Membranes in White Rats at Exposure to Chemical Environmental Factors

The Fluorescent Probe Method in Investigation of the State of Erythrocyte Membranes in White Rats at Exposure to Chemical Environmental Factors

Age-related features of activity of free radical oxidation in erythrocyte membranes and blood plasma in postinfarction cardiosclerosis in rats

Aim. To determine the presence of lipid and protein peroxidation products in erythrocyte membranes and blood plasma in rats of different ages in an intact state and with developed postinfarction cardiosclerosis.&#x0D; Methods. In rats aged 4, 12, 24 months postinfarction cardiosclerosis was modeled by coronary occlusion. In blood plasma and erythrocyte membranes, products reacting with thiobarbituric acid and carbonyl derivatives of protein amino acid residues were determined.&#x0D; Results. In erythrocyte membranes of intact animals aged 12 months, a decrease of the content of thiobarbituric acid-reacting products was revealed in comparison with 4 month-old animals, and in 24 months-old animals the index significantly exceeded the values of young subjects. In the blood plasma of intact animals aged 12 and 24 months, an increased content of thiobarbituric acid-reacting products with respect to rats aged 4 months was revealed. In postinfarction cardiosclerosis, an increase in the accumulation of thiobarbituric acid-reacting products was observed in erythrocyte membranes of 4 and 24 months-old animals. In blood plasma, an increase of this parameter was noted only in the group of 4 months-old animals with postinfarction cardiosclerosis. In erythrocyte membranes of intact rats of all age groups, no differences in the level of carbonyl derivatives of protein amino acid residues were observed, and in blood plasma it significantly increased with age. In 4 and 12 months-old animals with postinfarction cardiosclerosis, significant increase of carbonyl derivatives of protein amino acid residues was mostly pronounced in erythrocyte membranes. In 24 months-old animals with postinfarction cardiosclerosis, this parameter in the membranes and blood plasma was stable.&#x0D; Conclusion. The intensity of processes of cell membrane and blood lipid peroxidation has pronounced age-dependent features that persist in postinfarction cardiosclerosis; proteins of erythrocyte membranes of intact animals are subject to peroxide modification to a lesser degree than blood plasma proteins; in postinfarction cardiosclerosis formation in 4 and 12 months-old animals, carbonyl derivatives of protein amino acid residues are more intensively accumulated in erythrocyte membranes compared to blood plasma.

The Kinetics of Thermal Denaturation of Acetylcholinesterase of the Rat Red Blood Cell Membrane during Moderate Hypothermia

The thermostability of acetylcholinesterase of rat erythrocyte membranes in the norm and moderate hypothermia was studied. It is shown that the kinetics of the thermal denaturation of acetylcholinesterase is nonlinear and corresponds to a model that involves two-step denaturation, fast and slow, of the enzyme’s native form. The rate constants of the fast phase, k1, are much higher than those of the slow phase, k2, while the energy of the fast phase activation is lower by only 19.4% compared to that of the slow one. Short-term moderate hypothermia is shown to increase k1 and decrease the index of relative activity of the intermediate form of acetylcholinesterase (parameter β), leading to significant lowering of the activation energies of both stages; parameter β becomes more temperature dependent. The prolongation of hypothermia up to 3 h mainly contributes to a decrease in k1 and k2 relative to short-term hypothermia and the activation energy of denaturation increases. These data support the hypothesis according to which the structure of acetylcholinesterase is labilized at the initial stages of the development of the hypothermic state and stabilized during prolonged hypothermia.