Vol 165, No 5 (2018)

We studied the effect of α₂-adrenoreceptor agonist clonidine hydrochloride in concentrations of 10^—9-10^—6 M on inotropy, chronotropy, and coronary flow in Langendorff-isolated heart of adult rats. It was found that α₂-adrenoreceptor agonist changed all studied parameters. Left ventricular myocardium contraction force decreased after application of all tested concentrations, the maximum effect was observed at a concentration of 10^—6 M. Stimulation of α₂-adrenergic receptors in concentrations of 10^—8, 10^—7, and 10^—6 M produced a two-phase effect (initial increase and a subsequent decrease) on the coronary flow. Clonidine hydrochloride in the maximum concentration (10^—6 M) caused a decrease in HR in one group and an increase in the other.

Single injection of muscarinic cholinoceptor blocker atropine (1 mg/kg) to outbred male rats reduced β-adrenergic responsiveness of erythrocytes (by 2.2 times) and the content of epinephrine granules on erythrocytes (by 1.5 times), significantly increased HR and rigidity of the heart rhythm, and manifold decreased the power of all spectral components of heart rhythm variability. Stimulation of the central neurotransmitter systems increased β-adrenergic responsiveness of erythrocytes (by 15-26%), decreased the number of epinephrine granules on erythrocytes (by 25-40%), and increased HR and cardiac rhythm intensity. These changes were most pronounced after stimulation of the serotoninergic system. Administration of atropine against the background of activation of central neurotransmitter systems did not decrease β-adrenergic responsiveness of erythrocytes (this parameter remained at a stably high level and even increased during stimulation of the dopaminergic system), but decreased the number of epinephrine granules on erythrocytes, increased HR, and dramatically decreased the power of all components of heart rhythm variability spectrum. The response to atropine was maximum against the background of noradrenergic system activation and less pronounced during stimulation of the serotoninergic system. Thus, substances that are complementary to cholinergic receptors modulated adrenergic effect on the properties of red blood cells, which, in turn, can modulate the adrenergic influences on the heart rhythm via the humoral channel of regulation. Stimulation of central neurotransmitter systems that potentiates the growth of visceral adrenergic responsiveness weakens the cholinergic modulation of the adrenergic influences, especially with respect to erythrocyte responsiveness. Hence, changes in the neurotransmitter metabolism in the body can lead to coupled modulation of reception and reactivity to adrenergic- and choline-like regulatory factors at the level of erythrocyte membranes, which can be important for regulation of heart rhythm.

The contractile function of the heart was studied in adult frogs Rana temporaria under the influence of a toxic dose of isoprenaline under conditions of natural sinoatrial rhythm and during heart pacing. The dynamics of ventricular pressure was recorded with a Prucka MacLab 2000 instrument via a catheter introduced into the ventricle through the ventricular wall. Reduced (p<0.05) parameters of the pump function (HR, maximum ventricular systolic pressure, isovolumic indices dP/dt_max and dP/dt_min) and lengthening of QRS complex and QT interval on ECG attested to impairment of contractile function and electrical processes after exposure to isoprenaline. Electrical stimulation of the right atrium improved myocardial contractility and ECG parameters after the administration of isoprenaline.

Using a translation model of alcoholic cardiomyopathy in rats we showed the presence of an additional abnormal excitation focus in the area of the pulmonary vein lacunae in the left atrium and enhanced heterogeneity of the atrium depolarization pattern. These changes can determine electric instability of the myocardium and induce malignant heart rhythm disturbances including, sudden cardiac death.

We studied anti-ischemic activity of n-tyrozol under conditions of repeated transient myocardial ischemia in rats caused by repeated (5×3 min) occlusion of the left coronary artery. n-Tyrozol administered intraperitoneally in a dose of 20 mg/kg daily over 4 days before the ischemia modeling (the last injection 15 min prior to the start of the experiment) produced a clear-cut anti-ischemic effect: it reduced ST elevation and promoted more complete recovery of ECG during reperfusion. During reperfusion periods, n-tyrozol significantly decreased the risk of ventricular fibrillation and shortened the duration of tachyarrhythmia episodes (ventricular tachycardia and fibrillation).

Relatively short-term (2.5 or 5 h) exposure of Wistar rats to oxygen atmosphere at moderate pressure (1.10-1.15 atm) resulted in an increase in LPO level and reduction of antioxidant activity in the blood serum. An increase in malondialdehyde concentration 1 day after termination of the exposure was followed by a decrease in the inhibiting activity of free radical oxidation of liposomal phospholipids induced by Fe(II) ions (100 μm). Malondialdehyde concentration increased by 1.29 times already after 2.5-h exposure and did not changed when the duration of the exposure to oxygen atmosphere was prolonged to 5 h. These data confirm the necessity of using substances potentiating antioxidant defense of the body during exposure to normobaric oxygenation.

The effects of nootropic drug Semax on the neuronal network of the brain were studied by the resting state functional magnetic-resonance imaging (resting state fMRI). The study was carried out on two groups of healthy volunteers (11 men and 13 women aged 43.9±9.5 years). Resting state fMRI was carried out 3 times: directly before and 5 and 20 min after intranasal 1% Semax (14 subjects) or placebo (10 subjects). The topography of the resting state default mode network was studied. A greater volume of the default mode network rostral (medial frontal cortex) subcomponent was detected in the Semax group in comparison with controls. Resting state fMRI confirmed Semax effects on the neuronal network of the brain and demonstrated topography of these effects.

Original translational rat model of chronic heart failure provoked by experimental anterior transmural myocardium infarction was employed to examine the preventive action of anxiolytic Afobazole (15 mg/kg/day administered intraperitoneally during the first 15 days after coronary occlusion) on the development of the heart failure assessed in 3 months after infarction. Afobazole prevented the development of pathologic remodeling of the myocardium, maintained its inotropic function, and decreased the plasma level of brain natriuretic peptide known as a biochemical marker of chronic heart failure. In the myocardium, Afobazole down-regulated overexpression of the genes induced in chronic heart failure and assessed by corresponding RNA levels, which code angiotensin (AT1A-R), vasopressin (V1A-R), and glucocorticoid (GR) receptors as well as Epac2 protein. The revealed biochemical changes are consistent with the data on cardioprotective action of Afobazole.

Expression of genes that plays a significant role in the control of cellular redox homeostasis was studied during the development of drug resistance of human ovarian adenocarcinoma SKOV-3 cells to cisplatin. It was found that the development of drug resistance was accompanied by enhanced expression of the genes encoding the key antioxidant enzymes (SOD2, CAT, GPX1, and HO-1) and transcription factor Nrf2, as well as reduced expression of the gene encoding NOX5 isoform of NADPH oxidase. The results testify to redox-dependent development of the adaptive antioxidant response as an important process in the mechanism of formation of resistance to cisplatin.

The study examined the effects of millimeter electromagnetic waves at a frequency of 130 GHz corresponding to the molecular absorption and radiation spectra of NO and O₂ with the total exposition time of 6 h on tumor morphogenesis in 3- and 6-month-old tumor-prone BALB/c mice of both sexes. In experimental mice exposed to electromagnetic radiation, the development of cancer process was slowed down throughout the observation period; moreover, no macroscopic signs of the tumors were revealed. However, in contrast to control mice, experimental animals demonstrated the formation of pathological reactions reflected by hepatic biochemical indices accompanied by the development of dystrophic and microcirculatory alterations in the liver tissue.

We analyzed cytokine profile in blood serum of patients with uterine myoma and revealed significantly reduced level of IFNγ and a tendency towards a decrease in the levels of IL-1β and TNFα; the levels of IL-6, IL-8, and IL-12p70 did not differ from those in healthy women. The drop in the concentrations of factors responsible for inflammation and angiogenesis in tissues are unfavorable for proliferation and differentiation of the uterine tissues.

The expression of Epac proteins (exchange protein directly activated by cAMP) and calmodulin (CaM) was assessed by the content of the corresponding mRNA in biopsy specimens of cardiac atrium, left ventricle, and thoracic aorta of rats with alcoholic cardiomyopathy. In the myocardium, overexpression of Еpac1, Ерас2, and СаМ mRNA was found. The content of Epac2 mRNA in the left ventricle was elevated by 2.9 times (p=0.000001), in the left atrium by 3.2 times (p=0.00001), in the right atrium by 3 times (p=0.00001). In contrast to the myocardial tissue, the content of CaM mRNA in the thoracic aorta was not increased, but showed a tendency to decrease, when compared to the control values, while the level of Epac1 and Epac2 mRNA was increased. The assumption is made that regulatory proteins Epac and CaM can play a key role in arrhythmogenesis development under conditions of alcoholic cardiomyopathy.

Enzymatic hydrolysis of biopolymers of the cartilage tissue was studied for obtaining a complex of type II collagen peptides and glycosaminoglycan oligosaccharides. Hydrothermal hydrolysis in a high pressure homogenizer followed by enzymatic hydrolysis of the cartilage tissue biopolymers with proteolytic enzyme preparation Karipazim yielded a complex of collagen peptides and glycosaminoglycan oligosaccharides with molecular weights of 240-720 Da. Low molecular weight of the components increases their bioavailability. Entering into the cells (chondrocytes), low-molecular-weight peptides, disaccharides, and oligosaccharides as structural elements of the matrix can participate in the formation of fibrils of collagen and proteoglycans. Exogenous substances replenish deficient components of the matrix and/or their concentrations, affect the formation and strengthen the cartilage tissue. Thus, using cattle and porcine hyaline cartilages, we prepared a complex of biopolymers with lower molecular weights in comparison with previously developed nutraceuticals.

The effects of the pegylated form of glucagon-like peptide 1 (pegGLP-1) on oligopotent β cell precursors (CD45^—TER119^—CD133⁺CD49f^low) in the pancreas were studied in C57Bl/6 mice. Under conditions of streptozotocin-induced type 1 diabetes mellitus, intraperitoneal injection of pegGLP1 increased the content of β cell precursors and dithizone-stained cells in the pancreas. β Cell precursors of mice with diabetes demonstrated high self-maintenance potential. In contrast to pegGLP-1, native GLP-1 did not affect β cell precursors in diabetic animals. Treatment of a culture of β cell precursors from mice with diabetes induced the yield of dithizone-stained mononuclears. In conditioned mediums of dithizone-positive cells obtained as a result of differentiation of β cell precursors from mice with diabetes, insulin was detected after administration of pegGLP-1 (10^—7 M) and glucose (3 mmol/liter); the level of insulin increased with increasing glucose concentration (to 20 mmol/liter). The in vitro effect of pegGLP-1 did not differ from the effect of GLP-1 (10^—7 M).

JAK/STAT signaling pathway was examined comparatively during realization of growth potential of mesenchymal progenitor cells stimulated with diterpene alkaloid songorine or fibroblast growth factor. The stimulating role of JAKs and STAT3 on the mitotic activity and differentiation of progenitor cells cultured with songorine was revealed. Under these conditions, the study demonstrated suppression of fibroblast colony formation against the background of reduced number of actively proliferating CFU-fibroblasts and a drop of differentiation index of progenitor cells induced by pan-JAKs and STAT3 inhibitors. The observed changes were in almost complete agreement with the character of functional reactions of the progenitor elements in response to blockade of JAKs and STAT3 with fibroblast growth factor. In addition, blockade of JAKs with this factor enhanced the differentiation rate of the progenitor cells.

The function of synaptic transmission and presynaptic vesicular cycle in the neuromuscular synapses of the diaphragm was studied in transgenic APP/PS1 mice (Alzheimer’s disease model). The decrease in the quantal content of end-plate potential, intense depression of the amplitude of terminal plate potentials under conditions of lasting high frequency stimulation (50 Hz), a drastic prolongation of the synaptic vesicle recycling time in APP/PS1 mice in comparison with wild type mice were detected. Manifest dysfunction of the neuromuscular synapses, caused by disordered neurosecretion and recycling of the synaptic vesicles in the presynaptic nerve endings, was detected in the Alzheimer’s disease model on transgenic APP/PS1 mice. The study supplemented the notions on the pathogenesis of Alzheimer’s disease as a systemic disease, while the detected phenomena could just partially explain the development of motor disorders in this disease.

Immunohistochemical and morphometric analysis of the microcirculatory bed in the tumor and non-tumor parenchyma of the prostate was carried out with the use of endothelial cell marker CD34 in patients treated by high-intensity focused ultrasound (HIFU). The numerical density of microvessels in the adenocarcinoma focus did not correlate with the degree of its differentiation, while high values of this parameter were associated with lower incidence of local progression after HIFU. Effective HIFU ablation led to progressive fibrosis and significant reduction of the microcirculatory bed in zones of intact non-tumor glands in control samples; an inverse relationship between the degree of reduction of the microcirculatory bed and the probability of relapse was revealed. The use of HIFU in combination with androgen deprivation was associated with a decrease in numerical density of microvessels in zones of tumor and non-tumor parenchyma in patients with relapses.

Changes in the structure and cell composition of carinal lymph nodes were studied in humans during aging. Replacement of node parenchyma with fibrous connective tissue progressing with age was demonstrated. The medullary matter significantly prevailed over the cortical substance. The lymph nodes in the cortical substance were small and had no light centers; the concentration of mature CD20⁺ B cells was high; the paracortical area was fragmented and thinned and contained no CD4⁺ T helpers. Ki-67⁺ cells were absent in all structural components of the lymph nodes reflecting exhaustion of lymphopoietic function, which was determined by the replacement of the reticular tissue of the microenvironment with the connective tissue and by the absence of CD4⁺ T cells regulating cellular and humoral immunity. The disintegration of the reticular stroma in the sinus system that acts as a biological filter impairs the function of lymph purification.

Some electrocardiograms, e.g. electrocardiograms recorded in patients with atrial fibrillation, myocardial infarction, or receiving some medications, contain waves of small amplitude. Despite low amplitude, these waves can significantly affect correct identification of the pathological process and diagnosis. The approach proposed by us allows studying these small waves using the wavelet analysis by constructing the corresponding wavelet image of ECG using special software. Two examples of construction of wavelet images of ECG in atrial fibrillation and myocardial infarction are presented.