M. N. Maslova

Changes of gas exchange parameters and of functional-biochemical properties of erythrocytes in dynamics of experimental anemia in rats

In experiments on male Wistar rats, in a specially constructed computerized installation, O2 consumption by the animals in comparison with changes of hematological, biochemical, and rheological blood properties is studied after anemization—acute blood loss (12–15% of the total blood mass). An increase of the O2 consumption by the organism and tissues by 18–28% has been revealed for the first 7 days after the blood loss, in spite of a pronounced decrease of hematocrit and of the amount of erythrocytes and hemoglobin in peripheral blood by 20–25% of the initial level. There was a 5–10-fold increase of the content of immature erythrocyte forms—reticulocytes and a progressive rise of cell acidic resistance, which is characteristic of young erythrocyte forms. An increase of O2 consumption at a decrease of the blood oxygen capacity (a low hemoglobin level) seems to be due to the more efficient transport and yield of O2 to tissues. At the 3rd and 7th day after the blood loss, activity of Na,K-ATPase has been found to increase by 60% and 20%, respectively. Analysis of the erythrocyte rheological properties has shown that the maximal firmness of aggregates (Uq) and the aggregation rate (1/T) decrease progressively beginning from 3 days after the blood loss; index of deformability (Imax) turned out to be elevated by 7–11%, probably due to an increase of the cell membrane elasticity. The conclusion is made that changes of erythrocyte rheological properties are interconnected with changes of the Na,K-ATPase activity and are directed at optimization of blood circulation in large vessels and the capillary network.

Hyperbaria and stress

Performed on rats was study of the cause of appearance of stress reaction at action of hyperbaria upon organism. It was established that at the 5-h long action of gas mixtures (oxygen—nitrogen and oxygen—argon) under pressure of 0.35 and 0.5 MPa and partial pressure of oxygen of 0.02–0.03 MPa in camera 300 l in volume there was clearly realized stress confirmed by the corresponding markers. The appearance of stress was connected with density of gas mixture, which amounted to 6 g/l, that mechanically makes breathing difficult. On the other hand, use for respiration mixtures of elegas (SF6) with density of 6 g/l at normal pressure produces pronounced stress. At equal density, no difference was revealed in action of nitrogen, argon or elegas. Thus, use of high pressures requires light gases (helium, hydrogen, neon) that have low density.

Effect of Stress Actions on Some Hematological and Biochemical Parameters of Rat Blood and on Energetic Intermolecular Interactions in Lipid Extract under Effect of Light Radiation

Comparative study has been carried out on effects of the three-day long starvation, running, and their combination on morphological parameters of rat blood, lipid metabolism, and activity of blood Na,K-ATPase. Different effects of these stress factors on the blood erythrocyte composition have been shown. Starvation is accompanied by the most pronounced release of stored erythrocytes into blood, which results in a significant decrease of both the total amount of reticulocytes and in the complete absence of reticulocytes of I stage of maturity (the youngest). The running on a treadmill led to a significant increase in the total amount of blood reticulocytes and to a multifold increase of immature reticulocytes (RC-1 and RC-2), which can indicate some stress of the bone marrow erythroid stem line. The curve of acid resistance of blood reticulocytes has shown the animals to experience the greatest stress at a combination of starvation and running. Starvation and running also produced different effects on blood lipid characteristics. The content of triacylglycerides (TAG) in blood rose by 40% at starvation and decreased by 30% at running, a similar tendency being found for the atherogeneity index. The fatty acid composition of blood phospholipids at running and its combination with starvation practically did not differ from control. A change of Na,K-ATPase activity, which is so typical for reactions of various kinds of stress sharply fell at starvation (by 22%), but increased at running (by 13%) and decreased markedly at combination of these actions. The absorption spectra of the whole blood lipid extracts of the rats subjected to various stress actions showed that organic substance with coupled bonds, which absorbs light within diapason of 360–620 nm, is extracted from the blood (at different amount depending on the kind of action). The absorption of light in diapason of 400–410 nm has been found to belong to the Soret band of ferroheme and ferriheme. The shift of Soret band indicates an electron transitions in the iron cation. By the change and disappearance of Soret band it is possible to judge about the processes occurring in the lipid extract. Disappearance of the Soret band from the lipid extract indicates formation in it of the steady radicals as a result of the ferriheme disintegration due to accumulation of energy in porphyrin, which does not seem to occur in the blood cell membranes. The iron atom in the ferriheme molecule is known to accept electron and to yield a part of energy, probably to porphyrin. Then ferroheme yields electron and becomes ferriheme with an excess of the energy in porphyrin. Hence, at admission of the next electron to the iron atom the porphyrin molecule is to get rid of the energy obtained earlier to prevent its disintegration. The heme is possible to be an accumulator and distributor of energy in tissue.

Changes of physiological and biochemical characteristics of rat erythrocytes after blood loss

In experiments on Wistar male rats, changes are studied of erythrocyte hematological, biochemical (activities of transport ATPases), and rheological properties (capability for aggregation and deformability) 7 days after bloodletting of 12–15% of the total blood mass. It has been shown that alongside with an elevation of erythrocyte volume and of the number of immature cells—reticulocytes, there was a statistically significant increase of Na,K-ATPase and Ca-ATPase activities in the whole erythrocytes and in their membrane preparations—ghosts, the increment of activity in the case of Na,K-ATPase being essentially higher in the whole cells. This indicates the appearance of an enzyme activator inside the erythrocytes. There are also revealed a decrease of firmness of erythrocyte aggregates, a deceleration of spontaneous aggregation, and an increase of index of erythrocyte deformability. The conclusion is made that changes of erythrocyte rheological properties are interconnected with changes of the Na,K-ATPase activity and are aimed at optimization of blood circulation in large vessels and capillary network.

Changes of Functional and Biochemical Blood Parameters in Wistar Rats and in Spontaneously Hypertensive Rats of the SHR Line during Short-Term and Long Tredmill Running

Effects were studied of single (40 min) or repeated exercise load (tredmill running, 14 m/min, 30 min) on the physiological and biochemical blood parameters characterizing the organism energetic and metabolic processes in complex experiments on male Wistar rats, on spontaneously hypertensive rats of the SHR line, and their normotensive control WKY. The mixed blood was used for determination of hematocrit, red blood cell count, hemoglobin concentration, level of 2,3-diphosphoglycerate (2,3-DPG) in red blood cells, erythrocyte acetylcholinesterase (AChE) activity, glucose, cholesterol, and triglyceride concentration, as well as plasma corticosterone level. To assess the erythrocyte population characteristics, the acidity erythrogram was determined. The weights of adrenal glands and spleen were evaluated. The single running induced a typical stress-response. After the repeated exercise load (the 7–14-day running), Wistar and WKY rats were well adopted to the load, unlike the SHR line rats that were practically not adapted to the repeated tredmill running.

Repeated effect of hyperbaria on rat blood system

The reactions of the blood system in male Wistar rats to repeated effects of nitrogenoxygen hyperbaria (pressure 0.5 MPa, density of gas medium 6 g/l, pO2 = 0.02–0.03 MPa) were studied. Rats were placed into a pressure chamber for 5 h-in 24, 72, and 120 h after first exposure (ambient air pressure control). The red blood cell parameters were analyzed and the general condition of animals was estimated. It was established that after first exposure the stress reaction developed in rats with all objective stress markers (corticosteroid and adrenal ascorbic acid levels). On repeated exposure after 24 h, almost complete normalization of all stress markers occurred except for the increased plasma hemoglobin level as a result of impaired erythrocyte membrane permeability. After repeated exposures in 72 and 120 h, the stress markers recurred. After exposure in 120 h, the general condition of animals sharply deteriorated: they did not move in the “open” field, could not hold themselves on a horizontal bar and were mainly lying. The immobilization stress control showed that after the initial stress reaction rats recovered completely with no changes in the blood system and general condition of animals occurred on repeated exposures. We believe that the hyperbaria-induced stress is associated with breathing difficulty under pressure. Thus, the repeated effect of hyperbaria is a harmful factor which causes no habituation.

Changes of Rheological and Hematological Parameters in Rats of Wistar and SHR Lines at Single and Multiple Tredmill Running

In experiments on rats of the Wistar line and on spontaneously hypertensive animals of the SHR line, a complex study was performed of rheological (deformability and aggregation properties) and hematological parameters of erythrocytes at the single (40 min) and multiple (20–30 min for 7 and 14 days) exercise load (a forced tredmill running at a rate of 14 m/min). It has been shown that rats of both lines respond to the single, sufficiently light exercise load by a manifestation of stress-reaction. After the repeated exercise load, all stress-induced changes were leveled and replaced by adaptation to this action in Wistar rats, but not in the SHR line rats. The hypertensive rats were characterized by a greater fatigue and refusal of the tredmill running; therefore, this load to them had to be shortened to 20 min. For the 1st week of running, no statistically significant differences in the studied parameters were found between rats of the Wistar and SHR lines; however, by the 14th day of training, substantial differences between these lines were noticed: the Wistar rats were easily adapted to the tredmill running, whereas the SHR animals completely refused to run. At the single running, the stress-polycythemia, an increased hematocrit, a decreased hemoglobin concentration per erythrocyte, an increased plasma corticosterone level, and changes of blood rheological characteristics were shown, the erythrocyte deformability and the spontaneous aggregation rate under the stress conditions being in the direct positive correlational dependence that was absent in control. The Wistar rat training to the exercise load for 14 days led to normalization of the parameters, which indicates a favorable effect of trainings on the animal health state.