Body Of Laboratory Animals Research Articles

Assessment of the biological effect of natural silicon when entering the body of experimental animals with drinking water. Part 1

Introduction. The biological effect of natural silicon (Si) and its hygienic regulation in drinking water still remain subjects of controversy in the scientific literature and in the practice of providing favourable conditions for water use by the population. In this regard, an assessment was made of the effect of natural silicon contained in drinking water in concentrations close to the maximum permissible concentration on the body of laboratory animals.
 Materials and methods. Drinking waters containing natural Si at MPC levels in water were studied, their effect was assessed in a three-month experiment on 80 white outbred male rats. Observations were made of the general condition, appearance of the animals, body weight dynamics, water consumption. 
 The morphological composition of whole blood was studied. Biochemical indices of the condition of internal organs, including the liver, were determined 
 in serum samples (the ALT and AST activity, the level of total protein and albumin), pancreas (α-amylase activity), kidneys (creatinine content), as well as lactate dehydrogenase activity as a nonspecific indicator of tissue damage.
 Results. In animals received 17±3.4 mg/L silicon with drinking water at a hardness of 2.25±0.47 mg-eq/L, a significant decrease in ALT activity was found on the 30th and 90th days of the experiment, AST – on 90th day, increase in the content of total protein and albumin in the serum on the 30th day of the experiment. Drinking water with silicon concentrations of 20.5±4.1 mg/L and hardness 3.55±0.76 mg-eq/L decreased ALT activity and serum creatinine concentration on the 30th day and increased amylase activity on the 90th day of the experiment. The animals had the highest water consumption and intake of silicon from drinking water over the first month of the experiment.
 Limitations. Limitations of the study are related to the short duration of observation and the small number of points for determining biochemical parameters over time.
 Conclusion. Consumption of drinking water containing natural silicon for 90 days led to changes in biochemical indices, largely indicating the positive effect of the element in concentrations of 17±3.4 mg/L and 20.5±4.1 mg/L on the body of laboratory animals.

The results of an experimental toxicological assessment of the pharmaceutical substance ambroxol hydrochloride, justification of the maximum permissible content in the air of the working area

Introduction. Ambroxol hydrochloride is a biologically active substance used as a pharmaceutical substance in the manufacture of medicines for secretolytic therapy in the case of acute and chronic bronchopulmonary diseases. To date, there is no hygienic standard for the safe content of substances in the air of the working area in the republic.
 The study aims to substantiate and develop the maximum permissible concentrations and hazard class of the pharmaceutical substance ambroxol hydrochloride in the air of the working area.
 Materials and methods. The authors have conducted experimental toxicological studies of the pharmaceutical substance on animals (rats, mice, rabbits) in accordance with the requirements of technical regulatory legal acts and recommendations of methodological documents regulating the justification of hygienic standards.
 Results. Scientists have found that the pharmaceutical substance ambroxol hydrochloride, when injected into the stomach and inhaled, is classified as a low-hazard substance at an average lethal dose/concentration (according to GOST 12.1.007-76), has a mild irritant effect on the skin and moderate on the mucous membranes of the eyes, does not exhibit a skin-resorptive effect, is characterized by a weak cumulative effect and does not it has sensitizing activity. Under the conditions of inhalation of the substance into the body of laboratory animals (rats), the threshold values of acute and chronic harmful effects of this pharmaceutical substance were at the level of 90 mg/m3 (in terms of the effect on the functional state of the nervous activity of rats) and 30 mg/m3, respectively (in terms of changes in behavioral indicators, weight and mass coefficient spleen, blood glucose, alanine aminotransferases and urea) accordingly.
 Conclusion. Based on the experimental results of the toxicological assessment, the authors have justified the standard of permissible content of the pharmaceutical substance ambroxol hydrochloride in the air of the working area at the level of 4.0 mg/m3, they also have established the hazard class of the substance according to GOST 12.1.007-76 (class 3, medium-hazard substances).
 Ethics. The Bioethics Commission of the State Enterprise "SPCH” has approved the use of laboratory animals for experimental purposes (Protocol No. 1 dated 03/04/2020). The treatment of animals was in accordance with the provisions of Directive 2010/63/EU of the European Parliament and of the Council of the European Union of September 22, 2010 on the protection of animals used for scientific purposes.

Adaptation of epizootic brucella strains to the conditions of artificial nutrient media and the body of experimentally infected animals

Brucellosis remains an urgent problem to date. The preservation of brucellosis infection foci in regions with traditionally developed animal husbandry poses a danger of introducing the pathogen into safe territories, spreading among susceptible livestock and the risk of human infection. When fresh foci of brucellosis occur in an area with long-term well-being, objective data on the causative agent of infection are of great importance. The purpose of the research is to obtain an objective result of laboratory studies when diagnosing brucellosis in cattle in a fresh outbreak of infection and to evaluate the effectiveness of a set of diagnostic methods used in the work. The research was carried out in production veterinary and scientific laboratories. It was found that brucella, forming a fresh source of infection in cattle herds against the background of long-term well-being, had active antigenic properties. In 42% of infected animals (5 out of 12 animals), brucella of the epizootic strain caused the synthesis of specific immunoglobulins. Isolated brucella cultures were characterized by a weakly expressed ability to adapt to the conditions of an artificial nutrient medium and the body of laboratory animals. In the conducted studies, the probability of isolating the causative agent of brucellosis from animals that respond positively to serological examination was 20%. The objective data obtained on the properties of brucellosis pathogens circulating among susceptible animals in a fresh outbreak of infection made it possible to determine its species differences; establish factors and ways of introducing brucella, predict the course of infectious and epizootic processes, make a timely decision on carrying out health and preventive measures using effective methods and means.

Research on the specific toxicity of the drug “BTF plus” – a means for nor-malizing metabolic processes in animals and poultry

Laboratory studies were conducted to determine the subacute toxicity and tolerance of the veterinary drug “BTF plus” on white rats, dogs, and guinea pigs. The “BTF plus” preparation is a complex vitamin and mineral preparation based on butophosphane, L-carnitine, and cyanocobalamin, which normalizes and corrects metabolic processes in animals and poultry. The drug is used for various types of animals and poultry as a stimulating, tonic and general strengthening agent for obstetric pathologies (difficult births, postpartum complications, paresis, eclampsia, sexual cycle disorders); metabolic disorders caused by irrational feeding, malnutrition, asthenic syndrome, etc.; anemia with helminthiasis; secondary anemias, as an additional means in the treatment of magnesium and calcium deficiency; to increase muscle activity, with significant loads, overstrain and exhaustion in animals; to increase the body's resistance to various pathogens; to stimulate growth, development and live weight gain in young animals and poultry; as an additional means in the treatment of diseases caused by various factors (infectious and non-infectious origin). When administered subcutaneously to rats, the drug “BTF plus” under the conditions of a subacute toxicological experiment in doses (by absolute weight of the drug) of 200.0, 1000.0, and 2000.0 mg/kg of body weight does not cause hemo-, hepato- and nephrotoxic effects on the body of laboratory animals, but on the contrary, stimulates hematopoietic processes and has a positive effect on metabolic processes in their body. Subcutaneous administration of the drug “BTF plus” to dogs in doses (by absolute weight of the drug) of 200.0, 1000.0, and 2000 mg/kg of body weight for ten days does not cause hepatotoxic and nephrotoxic effects on the body under the conditions of a subacute toxicological experiment, but on the contrary, stimulates hematopoietic processes and has a positive effect on metabolic processes in the body of target animals. The tolerance of guinea pigs to the drug “BTF plus” was studied. It was established that the drug does not hurt the body and behavior of ants when administered subcutaneously in doses (based on the absolute weight of the drug) (5000,0–15000,0) mg/kg of body weight. Further studies will be the next stage of pre-registration tests aimed at studying the embryotoxic and carcinogenic effect of “BTF plus”, which is mandatory material of the “Safety and residue studies” section of the dossier for this medicinal product.

Toxicological studies of additives feed endoforce multi on laboratory animals

The creation of new drugs and feed additives is an urgent task that contributes to the growth of the efficiency of the livestock and poultry industries of agriculture, especially during the period of import substitution in the Russian Federation. An experimental study of possible changes in the body of laboratory animals after single or multiple uses of new feed additives is necessary for the toxicological assessment of newly created products. Single intragastric administration of feed additive Endoforce Multi containing live vegetative cells and spores of cultures: Bacillus subtilis B-5449, Bacillus subtilis B-1323, Bacillus subtilis B-3679 - 5.0 109 CFU / ml, at a dose many times higher than recommended, did not lead to the death of laboratory animals, which confirmed the absence of its acute toxicity. Over the entire observation period, the authors did not note any disturbances in the rats’ behavioural reactions and physiological states. Determination of chronic toxicity was carried out for 30 days. The studied suspension of the feed additive was given with water to rats of the experimental groups at doses: 1st - 100 mg, 2nd - 150 mg and 3rd - 200 mg per head. At the end of the empirical study, an increase in the number of erythrocytes by 2.68–3.72 1012/l, haemoglobin - by 41.50–61.58 g/l in laboratory animals of the experimental groups compared with the control ones was revealed, which indicated an increase in blood oxygenation and the organism as a whole. In addition, in the rats of the experimental groups, a decrease in the content of urea in the blood to 3.14 ± 0.53 - 4.68 ± 0.41 mmol / l and creatinine to 32.26 ± 5.18 - 48.13 ± 6.23 µmol/l. The opposite trend was observed when determining the serum activity of alkaline phosphatase, which increased by 39.0–52.6% in intact individuals, which indicated dynamic processes of growth, formation and development of the skeleton. According to the results of the autopsy of the rats of the studied groups, regardless of the dose of the introduction of the feed additive Endoforce Multi, no pathological changes in the colour, consistency and size of the internal organs were registered.

Evaluation of modern enterosorbents: possibilities and prospects

Absolutely all preclinical studies involve three groups of experiments: preclinical studies of the pharmacokinetics of the substance, including toxicokinetics, preclinical studies of the pharmacokinetics of the drug and the clinical study of pharmacokinetics on target animals. Pharmacokinetic studies of native drugs are complex because they usually involve the administration of complex components. Thus, only the use of the whole complex of pharmacognostic, chemical, spectral, physicochemical and biological methods can provide an objective assessment of the authenticity and quality of medicinal herbal raw materials and medicinal herbal preparations. The study used Wistar white rats, weight 150-160g according to the Guidelines for Evaluation of Medicinal Products (3). The purpose of the study was to evaluate the pharmacokinetic properties of a new feed additive in the form of a premix of sorbents and phytocompositions: milk thistle (DV-silibinin, Pharmcenter VILAR CJSC), thyme (DV-timol, Akhma100). Supplements in the form of finished dosage forms were standardized for the active substance, and have a constant composition. Thus, it allowed to create a study design for a new substance in one animal species. Since the composition of the sorption component was studied earlier, the introduced substances were considered separately and in combination with sorbents. After a single injection, the linearity of the pharmacokinetics was assessed, based on the administered different doses, the analysis of the main biochemical parameters of the blood was carried out, and the bioavailability was also calculated. Thus, the new premix based on sorbents and plant substances in the form of milk thistle and thyme does not have a negative effect on the body of laboratory animals. As a result of the studies, LD50 and LD100 were not established for the drug, the drug is classified as low-toxic, belongs to the fourth hazard class according to GOST 12.1.007-76 "Harmful substances", which allows further toxico-therapeutic tests.

Assessment of the toxic effect of 3-methylaminopropiophenone hydrochloride on the body

Introduction. In modern medical practice, fluoxetine hydrochloride (prozac), referred to the group of highly effective antidepressants, is widely used for the treatment of mental disorders. In Russia, the domestic production of the drug with an economically feasible production technology has been managed. In the synthesis of fluoxetine, the most important stage is the preparation of the main intermediate – 3-methylaminopropiophenone hydrochloride. Data on the toxic effect of this substance on the body in the open press, including in the international database PubChem, are not available. The research aim was the study on the toxic effect of 3-methylaminopropiophenone hydrochloride on the body of laboratory animals. Materials and methods. When studying the toxic effect of 3-methylaminopropiophenone hydrochloride in experiments on rats, the modes of single inhalation and subacute intragastric methods of exposure were reproduced. The effect of the substance on the condition of animals was assessed by the results of peripheral blood studies, biochemical blood serum parameters, morphological changes in internal organs including liver, kidneys, heart, stomach, pancreas and thyroid glands. Integral parameters were also used. Results. The results of the examination of animals subjected to acute inhalation intoxication and subacute intragastric exposure showed the same type of the changes in the peripheral blood and biochemical profile. The intake of 3-methylaminopropiophenone hydrochloride did not cause significant changes in the peripheral blood. The biochemical profile of the animals showed an increased activity of AST, ALT and alkaline phosphatase. In the blood serum of the primed rats, an increased content of total cholesterol, triglycerides and urea with a reduced content of protein and bilirubin was found. The impact of 3-methylaminopropiophenone hydrochloride at the morphological level revealed vascular disorders in all internal organs and moderately severe fatty degeneration of the liver and kidneys. In some parts of the liver, there was small-focus multi-lacular necrosis which covered groups of hepatocytes. Limitations. The investigation is limited to the study on the toxicological characteristics of 3-methylaminopropiophenone hydrochloride. In accordance with the directive documents on the protection of experimental animals, the number of in vivo experiments is limited which is connected with the dangers of animals and with public ethical views on in vivo experiments. Conclusion. Different methods of intake of 3-methylaminopropiophenone hydrochloride under the conditions of acute inhalation and subacute intragastric experiments lead to a number of disorders of the hepatobiliary system with a negative impact on the common health status of the body. As an additional preventive measure to minimize the risk of acute and chronic intoxication in industries where contact with the substance is possible, including those involved in the synthesis of fluoxetine, an extended list of biochemical blood tests, ultrasound obsservation of the liver as part of periodic medical examinations of workers can be offered.

Features of the Distribution of Mast Cell Populations in Lungs and Spleen During Simulated Hypoxic Hypoxia

The aim of research was to study the distribution of mast cell populations in the lungs and spleen depending on their expression of proteases in normal conditions and different periods of simulated hypoxic hypoxia.Material and methods. Hypoxic hypoxia was modeled on 87 outbred male rats using 200 liter chambers. The animals were under experimental conditions for four months. Rats were removed from the experiment after 30, 60, 90 and 120 days. After the animals were removed from the experiment, the lungs and the spleen were removed and fixed in 10% neutral buffer solution of Labiko formalin. Lung and spleen preparations were stained with hematoxylin and eosin and according to Van Gieson. For immunohistochemical studies, a panel of monoclonal antibodies was used: Anti-Mast Cell Tryptase antibody, Anti-Mast Cell Chymase antibody.Results. When modeling hypoxia in the structures of the lungs at the terms of 30 and 60 days, the content of predominantly tryptase-positive cells increased, and by the 90th and 120th days, the content of chymase-positive cells increased. By the end of the experimental exposure, the number of tryptase-positive cells increased by 3 times, and chymase-positive – by 7,7 times compared with the control. As the duration of the experiment increased, the presence of tryptase-positive cells in the spleen increased by 3,5 times, chymase-positive cells – by 7 times in the structures of the red and white pulp.Conclusion. During the formation of chronic hypoxic hypoxia in the body of laboratory animals, there is a redistribution of mast cells expressing tryptase and chymase. The most significant increase in the number of chymase-positive mast cells was noted both in the lungs and in the spleen.

Analysis of the pharmacokinetic properties of a native drug on the basis of a complex of sorbents

Absolutely all preclinical studies involve three groups of experiments: preclinical studies of the pharmacokinetics of the substance, including toxicokinetics, preclinical studies of the pharmacokinetics of the drug and the clinical study of pharmacokinetics on target animals. Pharmacokinetic studies of native drugs are complex because they usually involve the administration of complex components. Thus, only the use of the whole complex of pharmacognostic, chemical, spectral, physicochemical and biological methods can provide an objective assessment of the authenticity and quality of medicinal herbal raw materials and medicinal herbal preparations. The study used Wistar white rats, weight 150-160g according to the Guidelines for Evaluation of Medicinal Products (3).The purpose of the study was to evaluate the pharmacokinetic properties of a new feed additive in the form of a premix of sorbents and phytocompositions: milk thistle (DV-silibinin, Pharmcenter VILAR CJSC), thyme (DV-timol, Akhma100). Supplements in the form of finished dosage forms were standardized for the active substance, and have a constant composition. Thus, it allowed to create a study design for a new substance in one animal species. Since the composition of the sorption component was studied earlier, the introduced substances were considered separately and in combination with sorbents.After a single injection, the linearity of the pharmacokinetics was assessed, based on the administered different doses, the analysis of the main biochemical parameters of the blood was carried out, and the bioavailability was also calculated. Thus, the new premix based on sorbents and plant substances in the form of milk thistle and thyme does not have a negative effect on the body of laboratory animals. As a result of the studies, LD50 and LD100 were not established for the drug, the drug is classified as low-toxic, belongs to the fourth hazard class according to GOST 12.1.007-76 "Harmful substances", which allows further toxico-therapeutic tests.

On the issue of hygienic safety of new complex fertilizers with trace elements

Introduction. Currently, the most popular in agricultural production are complex chlorine-free mineral fertilizers with trace elements. The inclusion of trace elements in fertilizers improves plant nutrition, optimizes the effect of fertilizers. At the same time, trace elements are added to the fertilizer in the form of salts, in ionic form, most often, sulfates belonging to substances of hazard class 1-2, which can affect the toxicity of fertilizers and the safety of their production and use. To prevent a possible negative impact on human health and the environment for production, sale and use, it is necessary to conduct toxicological studies included in the state registration procedure. The aim of the study is to study the nature of the toxic effect on the body of laboratory animals (rats, rabbits, guinea pigs) of new complex chlorine-free mineral fertilizers with trace elements. Material and methods. Samples of liquid agrochemicals (preparations No. 1, No. 4, No. 5) and solid (preparations No. 2, No. 3) with different nitrogen, phosphorus and potassium content and different composition of trace elements in the form of salts were taken for research. The experimental work was performed on 90 nonlinear, sexually mature white male rats weighing 200-220 g, 30 purebred male rabbits weighing 3000-3500 g and 90 male guinea pigs weighing 350-400 g. During the work, existing methodological approaches and recommendations were used, including generally accepted informative methods of toxicological and statistical studies. Results. Based on the conducted studies, the parameters of acute oral and dermal toxicity, irritating effect on the skin and mucous membranes of the eyes, sensitizing effect of 5 samples of complex chlorine-free mineral fertilizers with trace elements were established. For all studied drugs, acute oral toxicity (LD50) > 5000 mg/kg body weight, acute dermal toxicity (LD50) > 2500 mg/kg body weight, mild irritating effect on the skin of rats (the average group-wide total score of the severity of the skin-irritating effect was 0.7 points for drugs No. 1, No. 4, No. 5 and 0.5 points for drugs No. 2 and No. 3), mild irritating effect on the mucous membranes rabbit eye shells (the average cumulative score of the severity of the irritating effect of samples of liquid fertilizers No. 1, No. 4, No. 5 was 1-3 points, solid fertilizers No. 2, No. 3 - 1-2 points), the absence of a sensitizing effect in guinea pigs within the standard research protocol (reactions of specific leukocyte lysis (RSLL) showed negative skin tests in guinea pigs of all experimental groups; the relative percentage of lysis did not exceed 10%). Research limitation. The definition of the hazard class was revealed in the study of the acute toxic effect of new complex chlorine-free mineral fertilizers with trace elements on the body of laboratory animals. Conclusion. Generalization of all the obtained results of experimental toxicological studies of complex chlorine-free nitrogen-phosphorus-potassium fertilizers with trace elements from the point of view of hygienic safety allows them to be classified as moderately dangerous substances (hazard class - 3).

Safety and Pharmacokinetics of the Substance of the Anti-Smallpox Drug NIOCH-14 after Oral Administration to Laboratory Animals.

Since most of the modern human population has no anti-smallpox immunity, it is extremely important to develop and implement effective drugs for the treatment of smallpox and other orthopoxvirus infections. The objective of this study is to determine the main characteristics of the chemical substance NIOCH-14 and its safety and bioavailability in the body of laboratory animals. The safety of NIOCH-14 upon single- or multiple-dose intragastric administration was assessed according to its effect on the main hematological and pathomorphological parameters of laboratory mice and rats. In order to evaluate the pharmacokinetic parameters of NIOCH-14 administered orally, a concentration of ST-246, the active metabolite of NIOCH-14, in mouse blood and organs was determined by tandem mass spectrometry and liquid chromatography. The intragastric administration of NIOCH-14 at a dose of 5 g/kg body weight caused neither death nor signs of intoxication in mice. The intragastric administration of NIOCH-14 to mice and rats at doses of 50 and 150 µg/g body weight either as a single dose or once daily during 30 days did not cause animal death or critical changes in hematological parameters and the microstructure of internal organs. The tissue availability of NIOCH-14 administered orally to the mice at a dose of 50 µg/g body weight, which was calculated according to concentrations of its active metabolite ST-246 for the lungs, liver, kidney, brain, and spleen, was 100, 69.6, 63.3, 26.8 and 20.3%, respectively. The absolute bioavailability of the NIOCH-14 administered orally to mice at a dose of 50 µg/g body weight was 22.8%. Along with the previously determined efficacy against orthopoxviruses, including the smallpox virus, the substance NIOCH-14 was shown to be safe and bioavailable in laboratory animal experiments.

Расчёт фармакокинетических и дозиметрических характеристик Lu-177-ЭДТМФ – потенциального препарата для радионуклидной терапии костных метастазов

Phosphonic acids labeled with beta-emitting radionuclides are promising radiopharmaceutical drugs for palliative therapy of bone metastases. Currently, the possibility of using a new osteotropic compound N,N,N’,N’-ethylenediaminetetrakis (methylene phosphonic acid) with lutetium-177 (177Lu-EDTMP) is being studied. The aim of the work is to develop a compartment mathematical model of the kinetics of 177Lu labeled osteotropic radiopharmaceutical drugs in the body of laboratory animals and calculate their pharmacokinetic and dosimetric characteristics based on it. To assess the stability of 177Lu-EDTMP in vivo, the characteristics of the distribution of free lutetium in the form of 177LuCl3 were also studied. To identify the model parameters and calculate the characteristics of radiopharmaceutical drugs, quantitative data on the bio-distribution of 177Lu-EDTMP and 177LuCl3 in the body of intact Wistar rats were used. A compartment model of kinetics has been developed and two approaches to the identification of its transport constants have been proposed – through the residual functional and using approximation by monoexponential functions. According to pharmacokinetic modeling, it was found that 177Lu-EDTMP is deposited in bone tissues (up to 55% of the administered dose). The calculated value of the apparent volume of distribution of 177Lu-EDTMP is approximately 200 times greater than the volume of blood plasma, the values of biological half-lives from bone tissues are 10-20 times higher than from internal organs. The excretion of 177Lu-EDTMP from the body occurs mainly through renal clearance. Comparative modeling with 177LuCl3 revealed high resistance of 177Lu-EDTMP in vivo. The highest values of absorbed doses are formed in the skeleton and kidneys with minimal radiation load on other internal organs and blood. The results obtained indicate the prospects for further studies of 177Lu-EDTMP and the possibility of its clinical application for the treatment of skeletal metastases.

Сравнительный анализ воздействия экспериментальных моделей светового десинхроноза на агрегационную активность тромбоцитов

The effect of different models of artificial light exposure on the aggregation activity of platelets of white male rats using a continuous Light-Light (LL) lighting model and models with alternating Light-Dark (12:10) and Light-Dark (18:6) light and dark modes was studied. Analysis of platelet aggregation activity was performed with a computerized 230LA "Biola" aggregation analyzer using the method of V.A. Gabbasov. It was found that under light exposure in the body of laboratory animals there is an increase of platelet aggregation activity accompanied by an increase in the parameters of the weighted average radius curve and the parameters of the light transmittance curve. Alteration of circadian rhythms in the form of impaired photoperiodism leads to an increase in platelet aggregation activity and provokes the development of microcirculatory disorders. The most pronounced changes in the microcirculatory bed by day 10 of the experiment are formed using the Light-Dark model (18:6).

Immunogenic properties of B. suis 245 strain brucellle culture

The article presents materials of study of antigenic, virulent and immunogenic properties of B. suis 245 strain brucelle culture in a comparative aspect with other vaccine strains in the body of laboratory animals. Transfers were made from the strains B. suis 245, B. abortus 19, 82, B. melitensis Rev-1 on dense nutrient medium after growth of lyophilized cultures of brucellas. A bacteriological study was conducted on meat-pepton glucose-glycerin broth (one test tube per object) and meat-pepton hepatic-glucose-glycerin agar (two test tubes per object) of pathological material (ten objects from each of the test animals). The identification of the isolated cultures of microorganisms was carried out by establishing an agglutination reaction on the glass with S- and R-anti-brucellosis serums. Regardless of the vaccine injection method, all animals that have been vaccinated with the B. suis 245 vaccine have shown resistance to artificial infection with virulent brucellosis. It was noted that in the group of guinea pigs vaccinated with a drug from the B. melitensis Rev-1 strain, resistance to infection was quite high. The protective properties of brucellosis vaccines are monitored in mice 10 days after vaccination. The test animals follow the observation for 7-10 days.

Microstructural assessment of organs and tissues in experimental immunosuppression and correction in animals

Abstract. Modern technological conditions of keeping and exploitation of animals and poultry do not exclude the negative impact of stress on their body. This leads to a decrease in the body’s resistance, an increase in morbidity and mortality. In addition, the quantity and quality of the products obtained are reduced. Stress prevention helps to increase the natural resistance of the body. The search for effective means of preventing stress reactions of the body in animal husbandry and poultry farming is an urgent problem of practical veterinary medicine. Polymineral feed additives of natural and artificial origin may exhibit adaptogenic properties. The purpose of this study was to give a microhistochemical assessment of the effectiveness of a mineral feed additive on some internal organs during experimental immunosuppression in laboratory animals. In the conditions of experimental immunosuppression, to identify the effect of a feed additive on the structure of organ cells and their metabolism. Materials and methods. To confirm the effectiveness of the mineral adaptogen, histological, morphometric and histochemical studies of stress-determining organs (adrenal glands), organs of excretion of metabolic products (kidneys) and the central organ of homeostasis (liver) were performed. As a result of the conducted studies, the organoprotective role of the mineral adaptogen was revealed. The most sensitive organs to the action of adverse factors (liver, kidneys, adrenal glands) have been identified. Morphometrically determined the reliability of morphological changes in them. During prophylactic feeding of mineral adaptogen in the studied organs, the revealed changes did not have total destruction, approaching the structure and metabolic processes in cells to the structure of these organs in intact animals. Scientific novelty. For the first time, a comparative microstructural, histochemical and morphometric assessment of some internal organs in the body of laboratory animals under conditions of artificially induced immunosuppression was carried out, confirming the organoprotective effect of a mineral adaptogen – a feed mineral additive of domestic production.

Морфогистохимическая оценка влияния кормовой минеральной добавки на органы пищеварения при экспериментальной иммуносупрессии у животных

Abstract. The conditions of keeping animals and birds are increasingly provoking stressful situations for them. The occurrence of stress helps to reduce the body's resistance and creates conditions for the development of diseases of various etiologies. With a decrease in resistance, the quantity of products and their quality decreases. It is possible to prevent stress in animals and poultry by using adaptogens of various origins. The search for optimal means that meet all the requirements of prevention remains to this day an urgent problem of practical veterinary medicine. The purpose of this study was to give a morphohistochemical assessment of the effect of a feed mineral supplement on the digestive organs during experimental immunosuppression in laboratory animals. In the conditions of experimental immunosuppression, to identify the effect of mineral feed additives on the structure of organ cells and their metabolism. Methods. To confirm the effectiveness of the mineral adaptogen, histological, morphometric and histochemical studies of the digestive organs were performed. As a result of the conducted research on preventive feeding of a feed mineral supplement of domestic production, its immune- and organoprotective role was revealed. The most sensitive organs to the action of adverse factors (lymphoid formations in the intestinal wall) have been identified. Morphometrically and histochemically determined the reliability of morphological changes in them. During prophylactic feeding of a feed mineral supplement of domestic production in the digestive organs, the revealed changes did not have total destruction, approaching the structure and metabolic processes in cells to the structure of these organs in intact animals. Scientific novelty. For the first time, a comparative microstructural, histochemical and morphometric assessment of the digestive organs in the body of laboratory animals under conditions of artificially induced immunosuppression was carried out, confirming the immune- and organoprotective effect of a feed mineral supplement of domestic production, which can be considered as a mineral adaptogen.

Results of pre-registration studies of the vaccine against Strangles of horses

Horse breeding in Yakutia is associated with year-round grazing and tebenevok keeping of horses. In herd horse breeding, the most common infectious disease is Strangles horses. In the republic, the incidence of Strangles from the total number of young horses is 57.8-62.7%, mortality - 4.0-22.0%. An effective method of combating this infection is vaccination. Based on this, we have developed a new inactivated vaccine against Strangles horses with an immunomodulator, made from the bacterial strain Str. equi "H-5/1", as an immunomodulator added centrate strain of bacteria Bac. subtilis TNP-3. Preclinical trials on laboratory animals (white mice, rabbits) showed that the vaccine protects up to 90% of white mice from experimental infection with a pathogenic strain of mytaceous streptococcus. According to the results of clinical observation, pathoanatomical autopsy, histological examination, it was established that the vaccine does not negatively affect the general condition of animals, does not have allergenic properties, does not cause pathological changes in organs and tissues, and does not have a toxic effect on the body of laboratory animals. Clinical trials were carried out on foals 6-8 months of age. The efficiency of immunization was 97.6%. With the introduction of the development in a separate farm, the economic effect per head will be 3.99 thousand rubles, per 1 ruble of costs - 6.65 rubles. In general, the republic will receive an economic effect in the amount of 49 million 356 thousand rubles. Thus, the method of specific prevention of Strangles horses developed by us is environmentally safe, highly immunogenic and cost-effective. Scientific and technical documentation and the vaccine against myta successfully passed the examination of the VGNKI of veterinary drugs. The vaccine is registered in the register of medicinal products for veterinary use (Rosselkhoznadzor of the Russian Federation) under registration number No. 71-1-27.21-4828 No. PVR-1-27.21/03691 dated 08.12.2021.

ТОКСИКОЛОГИЧЕСКАЯ ХАРАКТЕРИСТИКА, КЛАССИФИКАЦИЯ ОПАСНОСТИ И ОБОСНОВАНИЕ ПРЕДЕЛЬНО ДОПУСТИМЫХ КОНЦЕНТРАЦИЙ ФАРМАЦЕВТИЧЕСКОЙ СУБСТАНЦИИ МЕТФОРМИНА ГИДРОХЛОРИД В ВОЗДУХЕ РАБОЧЕЙ ЗОНЫ И АТМОСФЕРЫ

A toxicological and hygienic assessment of the pharmaceutical substance of metformin hydrochloride was performed using various regimens, doses and ways of entry into the body of laboratory animals. The conducted studies allowed us to establish the parameters of the toxicometry of metformin and the features of its biological action, which consist in the absence of an irritating effect on the skin and skin-resorptive properties, an allergenic effect on the body and weak cumulative properties and irritant effect on the mucous membranes of the eyes. Hazard classes of the metformin hydrochloride and hygienic regulations for this substance content in the air of the working area and atmosphere have been developed.

Сравнительный анализ применения наркозно-дыхательных контуров для ингаляционной анестезии у лабораторных животных

The article presents a study on the effect of inhalation anesthetics on the body of laboratory animals, depending on the choice of the respiratory circuit. As a result of the research, it was found that the most suitable circuit for inhalation anesthesia in laboratory animals is a semi-open breathing circuit.

Features of the course of metabolic processes in the body of laboratory animals with additional feeding of manganese asparaginate

Features of the course of metabolic processes in the body of laboratory animals with additional feeding of manganese asparaginate