Hemodynamic Parameters in Spontaneously Hypertensive Rats with Obesity and Chemically Induced Colitis during Probiotic Therapy.

We studied the dynamics of the main hemodynamic parameters in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats with visceral obesity and chemically induced colitis (CIC) against the background of probiotic therapy. Systolic BP, HR, and body temperature were recorded over 36 days using a wireless telemetry system. During 8 days (3 days before CIC induction and until the end of the experiment) the animals were intragastrically administered a probiotic based on Lactobacillus delbrueckii D5 strain. At baseline, systolic BP was significantly higher in the SHR group, while HR and body temperature did not differ in SHR and WKY rats. On day 8 after CIC induction, systolic BP, HR, and body temperature in SHR were significantly increased in comparison with the initial values. In the group of WKY rats, all indices at the end of the experiment remained at the initial levels. Probiotic therapy in SHR, in contrast to WKY rats, did not lead to normalization of body temperature and hemodynamic disorders resulting from CIC.

The Pattern of Granuloma Formation in the Liver of Rats as a Reflection of the Mechanism of Internalization of Submicron Silicon Particles.

A morphological analysis of the liver of Wistar rats was performed 2 months after a single intravenous injection of porous silicon particles of different sizes (60-80, 250-300, and 500-600 nm; 2 mg/ml, 1 ml). Histological, immunohistochemical, and electron microscopic methods showed the development of CD68+ granulomas in all experimental groups. Injection of 60-80-nm porous silicon particles led to the formation of single large granulomas (>2000 µm2), while 500-600-nm nanoparticles caused the formation of numerous smaller granulomas. The mechanism of involution of granulomas by apoptosis of Kupffer cells and the absence of subsequent connective tissue remodeling of the organ tissue is shown.

Influence of Interleukin-2 and Brain-Derived Neurotrophic Factor (BDNF) on the Size of Myocardial Infarction in Rats with Systemic Inflammatory Response.

We studied the influence of recombinant IL-2 and brain-derived neurotrophic factor (BDNF) on the size of the myocardial necrosis zone of rats with systemic inflammatory response syndrome (SIRS). A significant increase in the necrosis zone and the levels of proinflammatory cytokines was revealed in animals with SIRS in comparison with the control. The administration of IL-2 to animals with SIRS significantly reduced the size of the necrosis zone, which was paralleled by a pronounced increase in IL-2 and BDNF in comparison with the corresponding parameters in rats with SIRS that did not receive IL-2. Administration of BDNF to animals with SIRS was followed by normalization of TNFα and IL-1α levels, but did not lead to a decrease in the size of the necrosis zone.

The Use of Microencapsulated Autologous Thrombi for Modelling Chronic Thromboembolic Pulmonary Hypertension in Rats.

Here we developed a model of chronic thromboembolic pulmonary hypertension (CTEPH) using repeated intravenous administration of microencapsulated thrombi with a controlled rate of biodegradation. Autologous thrombi encapsulated in alginate microspheres with a diameter of 190±48 µm were intravenously injected to rats 8 times every 4 days. In the comparison group, nonmodified thrombi were injected. After 6 weeks, a significant increase in systolic pressure in the right ventricle, a decrease in exercise tolerance, and an increase in the index of vascular wall hypertrophy were revealed in the group receiving injections of microencapsulated thrombi in comparison with the group receiving nonmodified thrombi and healthy animals. Thus, the developed representative CTEPH model can be used to test promising pharmacological substances.

Effect of Probiotic Therapy on Hemodynamic Response Associated with Systemic Inflammatory Reaction and Antibiotic-Induced Dysbiosis in Chronic Experiments in Rats.

The effect of probiotic therapy on the main hemodynamic parameters was studied in Wistar rats with modeled syndrome of systemic inflammatory response resulting from chemically induced colitis complicated by antibiotic-induced dysbiosis. Using a wireless telemetry monitoring system in round-the-clock mode, the mean systolic and diastolic BP, HR, and body temperature were measured over 27 days. In the group of animals receiving no probiotics, a significant decrease in feed consumption and body weight loss were observed. By the end of the experiment, BP in this group was lower by 12% and HR was higher by 10% than in the control. In animals treated with a mixture of probiotic strains Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis, all the studied parameters returned to the initial values. Thus, we demonstrated the possibility of using probiotic drugs for the treatment of acute systemic inflammatory process, which should be considered in the development of new treatment protocols in veterinary and medicine.

Acute Effect of Selective Chemical Inactivation of Sympathetic or Parasympathetic Atrial Ganglionated Plexus Structures on Atrial Fibrillation Inducibility in Pigs.

We studied the role of both parts of the autonomic intracardiac nervous system in the pathogenesis of atrial fibrillation (AF). In 12 pigs weighing 39±3 kg, AF was induced by burst stimulation. Chemical inactivation of intrinsic cardiac neurons within the right atria was performed by transendocardial injections of liposomal neuromodulators into the dorsal part of the right atrial wall. Sympathetic and parasympathetic terminals were inactivated with 6-hydroxydopamine (6-OHDA, n=6) and ethylcholine aziridinium ion (AF64A, n=6), respectively. Neuromodulators were encapsulated in liposomes (LS) with diameters of 310±50 nm for OHDA and 290±50 nm for AF64A. LS-6-OHDA and LS-AF64A were injected into the ganglionated plexuses after measuring the baseline effective refractory period and assessing myocardial resistance to AF. These measurements were repeated 90 min after the injections. The optimal doses were 0.2 mg/kg for LS-6-OHDA and 0.4 mg/kg for LS-AF64A (in 4 ml of suspension). Immediately after injections of liposomal neuromodulators, almost all pigs showed an increase in HR, and a short-term BP elevation was observed in the LS-AF64A group. At the end of the experiment, similar decrease in the effective refractory period and similar increase in the resistance to AF were observed in all animals. Thus, selective chemical inactivation of cholinergic and adrenergic terminals of the intracardiac nervous system with liposomal neuromodulators increased the resistance to AF in an acute experiment. However, the short observation period does not allow making a definite conclusion about the role of the autonomic nervous system in the pathogenesis of AF, which requires verification of the obtained data in a chronic experiment.

Effect of Azithromycin on Myocardial Resistance to Ischemia/Reperfusion in Systemic Inflammatory Response Syndrome and Alimentary Obesity.

The study focuses on the effects of azithromycin on severity of ischemia/reperfusion myocardial injury during simulated systemic inflammatory response syndrome (SIRS) in primary visceral obesity (PVO). Total ischemia/reperfusion was modeled by Langendorff perfusion of isolated heart with following estimation of the size of myocardial infarction. SIRS was accompanied by an increase in blood levels of proinflammatory cytokines and LPS. Combination of PVO and SIRS produced no significant changes in the infarct size compared to the control. Administration of azithromycin to rats with PVO and SIRS resulted in pronounced alterations of biochemical and immunological parameters, although it did not affect the infarct size. In contrast, the use of tetracycline increased the size of myocardial infarction. This phenomenon should be taken into consideration in antimicrobial therapy.

Modeling of Acute Pulmonary Arterial Hypertension in Pigs Using a Stable Thromboxane A2 Analogue (U46619): Dose Adjustment and Assessment of Hemodynamic Reactions.

U46619, a synthetic analogue of thromboxane A2 was used for modeling acute stable and reversible pulmonary arterial hypertension. Administration of U46619 in high doses led to vascular collapse and inhibition of cardiac function. The doses of U46619 were empirically selected that allow attaining the target level of pulmonary hypertension without systemic hemodynamic disturbances. The possibility of attaining the target level of pulmonary hypertension and reversibility of changes after termination of U46619 infusion make this model attractive for evaluation of the efficiency of different therapeutic methods of treatment of pulmonary hypertension in large animals.

Morphological Analysis of the Respiratory Tract of Rats after Parenteral Administration of Silicon Dioxide Nanoparticles.

Morphological analysis of the respiratory tract of Wistar rats was performed after a single parenteral administration of 12-nm silicon dioxide nanoparticles (1 ml, 2 mg/ml, intravenously) was performed. On day 21 and in 2, 4, and 6 months after the administration of nanoparticles, the development of macrophage infiltration in the interstitium of the respiratory tract was demonstrated by histological and immunohistochemical methods. The pool of alveolar macrophages increased in 4 months after administration (p=0.004) and returned to the control values in 6 months. The number of mast cells did not significantly change at all stages of the experiment. Connective tissue remodeling in the interstitium of the respiratory tract was not observed throughout the observation period.

Restoration of ß-Adrenergic Signaling and Activity of Akt-Kinase and AMP-Activated Protein Kinase with Metformin in the Myocardium of Diabetic Rats.

We studied the effect of metformin (100 and 200 mg/kg/day, 4 weeks) on the adenylyl cyclasestimulating effects of ß-agonists and relaxin in the myocardial membranes and on activities of Akt-kinase, an effector component of insulin signaling, and AMP-activated protein kinase (AMPK), a cellular energy sensor, in the myocardium of rats with type 2 diabetes mellitus induced by high-fat diet and streptozotocin. Metformin normalized the ratio of adenylyl cyclase effects of ß1/2- and ß3-agonists in the myocardial membranes, that is reduced in DM2, and restored phosphorylation of Akt-kinase by Ser473 and AMPK by Thr172 in the myocardium of diabetic rats. The effect of metformin in a dose of 200 mg/kg/day was more pronounced. Thus, the cardioprotective effect of metformin is due to its ability to restore the adrenergic and insulin regulation in cardiomyocytes and their energy status.

Effect of Combined Antimicrobial Therapy on Ischemia/Reperfusion Myocardial Injury in Rats with Acute Inflammation of the Large Intestine against the Background of Alimentary Obesity.

We studied the effect of combined antimicrobial therapy with amoxicillin, metronidazole, and clarithromycin on the severity of ischemia/reperfusion myocardial injury in Wistar rats with alimentary obesity and acute inflammation of the large intestine. General ischemia/reperfusion was reproduced on Langendorff-perfused isolated hearts and infarct size was estimated. Acute inflammation of the large intestine was accompanied by an increase in the blood levels of proinflammatory cytokines. The presence of obesity and acute inflammation of the large intestine did not significantly affect the infarct size in comparison with the control. Administration of antimicrobial drugs to animals with obesity and acute inflammation of the large intestine led to a significant increase in the infarct size, which should be considered when prescribing antimicrobial therapy to patients with comorbidity.

Perivascular Innervation of the Pulmonary Artery in Human and Swine: A Comparative Study for the Development of an Experimental Model of Denervation.

For studying the possibility of using catheter denervation of the pulmonary artery for the treatment of pulmonary hypertension, large animals, such as pigs, are more suitable, because the diameter of the pulmonary artery in this case allows manipulation of the ablation catheter. The study of the perivascular adipose tissue of the trunk and bifurcation of the pulmonary artery in humans and pigs revealed differences in the density and diameter of nerve fibers, but their depth did not differ. Immunohistochemical analysis with different markers of the autonomic nervous system receptors revealed similar receptor profile in human and pigs, though the expression of all studied markers in pigs was less pronounced than in humans. These findings attest to similarity of the innervation of the pulmonary arteries in humans and pigs under normal conditions.

[Effects of hyper- and hypothermia on hemodynamic parameters in people of different age groups. Meta-analysis.]

Age-related changes in thermoregulation occur due to the deterioration of the adaptive capacity of the cardiovascular system caused by remodeling of the vascular wall and myocardium, capillary density reduction, changes in the synthesis and clearance of neurotransmitters and vasoactive substances, as well as the inhibition of the vegetative mechanisms of hemodynamic parameters regulation. A common way to simulate hyper- and hypothermal conditions is to use a suit with tubes to fill with water at different temperatures. The purpose of this work is to conduct a meta-analysis of the hemodynamic parameters shifts when modeling hyper- and hypothermia using such a suit in people of different age groups. As a result of the meta-analysis, it was found that heating the whole body is accompanied by a decrease in blood pressure (BP) and an increase in heart rate (HR). The reaction of hemodynamic parameters to hyperthermia does not significantly change with aging. Cooling of the whole body is accompanied by an increase in BP without changing the HR. In hypothermia, the amplitude of the elevation of the systolic BP is greater in older people.

[The effect of different types of bariatric surgery on the metabolic and hormonal parameters in rats with decompensed form of type 2 diabetes mellitus.]

Currently, one of the approaches to correct metabolic disorders in the type 2 diabetes mellitus (DM2) with obesity are bariatric surgery (BS), including sleeve gastrectomy (SG), gastric bypass (GB) and ileal transposition (IT). However, their effectiveness and impact on the hypothalamic signaling and hormonal status in severe forms of DM2 without obesity remain little studied. The aim of the work was to study the effect of IT, SG and GB on the insulin, leptin, ghrelin and glucagon-like peptide-1 (GLP-1) levels in the blood and on the expression of the genes encoding the main components of the hypothalamic signaling systems in rats with decompensated form of DM2, which was induced by a high-fat diet (3 months) and a single low dose of streptozotocin (25 mg/kg, 2 months after the start of the diet). In diabetic rats, a significantly expressed hyperglycemia, an impaired glucose tolerance, a decrease in glucose-stimulated GLP-1 level, a slight decrease in the insulin and leptin levels and an slight increase in ghrelin level were detected. In the hypothalamus, the expression of the genes encoding GLP-1 receptor, orexigenic agouti-related peptide (AgRP), as well as phosphotyrosine phosphatase 1B and SOCS3, the negative regulators of the leptin and insulin pathways was increased. In diabetic rats, the IT reduced the glucose levels 120 minutes after glucose load, increased the basal and glucose-stimulated GLP-1 levels, normalized the gene expression for phosphotyrosine phosphatase 1B, SOCS3, AgRP and GLP-1 receptor, which indicates the restoration of the hypothalamic signaling responsible for the control of energy metabolism and insulin sensitivity. In the case of SG and GB, an improvement in the glucose tolerance was found, and in the case of SG, an increase in the basal and glucose-stimulated GLP-1 levels was shown. However, no significant effect on the expression of the hypothalamic genes in SG and GB was found. Thus, IT is the most effective of all studied BS in the treatment of severe forms of DM2 without obesity.

Effect of Antiobiotic-Induced Disbiosis and Its Correction with Probiotics on Myocardial Tolerance to Ischemia-Reperfusion Injury in SPF Rats.

Changes in morphofunctional parameters of the isolated heart subjected to global ischemia-reperfusion were studied in SPF Wistar rats with antibiotic-induced dysbiosis (AID) treated with lyophilized yeast Saccharomyces boulardii and inactivated probiotic bacteria Lactobacillus reuteri KR2017. In contrast to S. boulardii, correction of dysbiosis with L. reuteri KR2017 against the background of gastric hypersecretion and standard antimicrobial therapy led to an increase in fat content and a decrease in free and bound water in tissues and to a significant reduction in myocardial infarct size caused by ischemia/ reperfusion injury.

Effects of Bariatric Surgeries on the Size of Myocardial Infarction and Ghrelin Level in Rats with Experimental Decompensated Type 2 Diabetes Mellitus.

The effects of bariatric surgeries (sleeve gastrectomy and ileal transposition) on the dynamics of changes in ghrelin level were studied in rats with severe decompensated type 2 diabetes mellitus under conditions of glucose challenge as well as on the size of myocardial infarction in these animals. Diabetes was modelled by high fat diet and a single administration of streptozotocin (25 mg/kg, intraperitoneally). Both bariatric surgeries significantly decreased glucose-induced ghrelin level in the blood of rats with type 2 diabetes mellitus, which attested to an increase in the tissue sensitivity to ghrelin. Sleeve gastrectomy resulted in a decrease in the size of myocardial infarction in diabetic rats, which was calculated as the ratio of the necrosis zone to the zone of the risk of myocardial infarction. Ileal transposition had no effect on this parameter. Our data can be used as the basis for optimization of treatment approaches when using bariatric surgery in the treatment of patients with severe forms of type 2 diabetes mellitus with a high risk of cardiovascular diseases.

Effects of Inhibitors of Necroptosis and Autophagy on Morphofunctional Characteristics of the Myocardium during Static Cold Storage of Donor Rat Heart.

Cardioprotective effects of necrostatin-1 (necroptosis inhibitor) and 3-methyladenine (autophagy inhibitor) were studied on the model of long-term cold preservation of rat heart. Addition of necrostatin-1 (490 nmol/liter) or 3-methyladenine (4.5 mmol/liter) to custodiol preserving solution reduced myocardial infarction size and improved left-ventricular function during reperfusion after 8-h preservation at 4°C. Inhibition of necroptosis and autophagy contributed to the cardioprotective effect under conditions of cold preservation of the donor heart.

Stimulation of Proliferation and Differentiation of Rat Resident Myocardial Cells with Apoptotic Bodies of Cardiomyocytes.

Using the cell model of regenerative cardiomyogenesis (formation of contracting cardiomyocyte colonies from resident stem cells), we found that the addition of cardiomyocyte-derived apoptotic bodies to the culture of neonatal myocardial cells stimulated proliferation and differentiation of cardiomyocyte precursors and the frequency of their contraction was 1.5-fold higher than in the control. Systemic administration of cardiomyocyte-derived apoptotic bodies to Wistar rats with chronic postinfarction heart failure during the early period of myocardial remodeling considerably improved the contractile function of the heart.

[CHANGE IN BCL-2 PROTEIN EXPRESSION IN NEURONS OF THE HIPPOCAMPAL AREAS AFTER THE APPLICATION OF ISCHEMIC CEREBRAL POSTCONDITIONING].

Bcl-2 protein expression was studied in hippocampal CA1, CA2, CA3 and CA4 pyramidal neurons in Mongolian gerbils (Meriones unguiculatus), of the in in the early (Day 2) and late (Day 7) reperfusion period after a 7-minute forebrain ischemia and following ischemic postconditioning (IPostC), as well as in sham-operated animals (n=60). In the latter, the highest level, of Bcl-2-expression was found in CA4 neurons, while the lowest--in-CA1 neurons (P<0.01). Reversible ischemic brain damage led to the increasing deficit of morphologically unchanged hippocampal neurons with the increasing duration of reperfusion period. This was accompanied by a significant decrease in expression of Bcl-2 in the early reperfusion period, but in the late reperfu- sion period this decrease largely disappeared. IPostC, applied as three episodes of ischemia-reperfusion lasting 15/15 seconds, contributed to significant increase in the number of morphologically unchanged CA1 and CA3 neurons in the early reperfusion period, while the expression of Bel-2 was increased in morphologically unchanged neurons in all the hippocampal areas. In the late reperfusion period after IPostC, the number of unchanged neurons was increased in hippocampal areas CA1, CA3 and CA4 (P<0.05), while a significant increase in Bcl-2 expression (by 12.7%, P<0.01) was detected only in CA1 neurons. The results suggest that the cytoprotective effect of IPostC in hippocampal CA1 area is realized through a mechanism leading to increased expression of Bcl-2 protein, i.e., by blocking apoptosis.

[Possibilities of cryopreservation of ovarian tissue for fertility preservation in cancer patients].

One of the effective methods of fertility preservation is an autologous transplantation of cryopreserved ovarian tissue. Currently, according to the world literature, after orthotopic autotransplantation of ovarian tissue 37 healthy children were born. In 2014 at the North-West Federal Medical Research Center it was established Cryobank of ovarian tissue, which is now kept 50 samples of ovarian tissue of man. Cryoconservation is performed by standard slow freezing. Autotransplantation of cryopreserved ovarian tissue has unique advantages over other methods of fertility preservation. This method does not lead to the postponement of anticancer therapy, safe for hormone-dependent cancer and can be performed regardless of the day of menstrual cycle and it is the only option for fertility preservation in prepubertal girls. The use of this method in clinical practice leads to restoration of endocrine function of the ovaries as well as of fertility in the future.