Nadezhda Yuryevna Khusnutdinova

Objective - To conduct a comparative evaluation of the efficacy of prophylactic correction using ademetionine and a complex of oxymethyluracil with N-acetylcysteine in a model of thioacetamide-induced toxicity. Materials and Methods. The study was performed on 56 male rats. Toxicity was induced by intraperitoneal administration of thioacetamide at 50 mg/kg body weight twice weekly for 100 days. The animals were assigned to four groups: negative control, positive control, and two experimental groups receiving thioacetamide in combination with either ademetionine or the oxymethyluracil-N-acetylcysteine complex. The corrective agents were administered one hour prior to the toxicant. On days 50 and 100, serum and urine biochemical parameters were assessed, along with gene expression in the liver and kidneys related to antioxidant defense, the glutathione system, apoptosis, and the cell cycle. Histological and morphometric tissue analyses were also performed. Results. The positive control group confirmed the development of chronic toxic hepatitis with progressive liver fibrosis. The use of a complex of oxymethyluracil and acetylcysteine demonstrated superiority over ademetionine in preventing long-term outcomes, with ademetionine primarily exerting an early metabolic effect without affecting the progression of liver fibrosis or structural tissue remodeling in the later stages. Regarding the kidneys, morphometric stress was observed by the end of the treatment period, most noticeable in the positive control group and during prophylactic administration of ademetionine. Conclusion. Under the conditions of intoxication considered, both compounds demonstrated a certain ability to modify late structural outcomes. The complex compound of oxymethyluracil with acetylcysteine demonstrated a more favorable profile at the late stage, while ademetionine was more effective at the early stages. These findings highlight the potential of antioxidant-targeted strategies for the prevention of adverse outcomes in chronic toxic injury.

The immune system is one of the most sensitive targets of the stress response, as reflected by alterations in lymphoid organs and hematological parameters. Paracetamol, one of the most widely used analgesics, is traditionally studied as a hepatotoxic agent; however, its effects on immunohematological parameters remain insufficiently explored, especially in combination with chronic stress. The aim of the study was to assess the effects of 28-day administration of paracetamol (1000 mg/kg), including under conditions of chronic unpredictable stress, on body weight, thymus and spleen weight coefficients, and hematological parameters in male and female rats. In males, chronic stress caused a significant decrease in leukocyte count (to 5,7×10 ⁹ /L; p=0,001), whereas paracetamol increased leukocyte levels compared to stress alone (p=0,001). Paracetamol reduced hemoglobin levels (129,5 g/L), while in combination with stress, hemoglobin was increased (141,1 g/L; p=0,001). In females, these changes were not observed; however, a significant decrease in platelet count was detected in all experimental groups (p=0,001). The thymus weight coefficient in females decreased after paracetamol administration (1,08; p 0,01), whereas in males it remained unchanged. A reduction in spleen weight coefficient was observed only in males under stress and combined exposure (p≤0,02).The data indicate a sex-dependent pattern of immunohematological changes associated with paracetamol administration, both alone and in combination with chronic stress. At the same time, the absence of endocrine parameter assessment does not allow the observed differences to be unequivocally interpreted as evidence of a stress-protective effect of paracetamol; these findings require further investigation with the inclusion of markers of hypothalamic-pituitary-adrenal and gonadal regulation.

Objective - The aim of the study was to experimentally assess the preventive effect of a complex of oxidized pectin and oxymethyluracil on chronic aluminum-induced hepatotoxicity in rats based on molecular and biochemical parameters. Materials and Methods. The experiment was conducted on 56 outbred female rats that received oral administration of aluminum hydroxide at a dose of 15 mg/kg and a chelate complex of oxidized pectin with oxymethyluracil (50 mg/kg) under various preventive and post-exposure regimens for 3-4 months. The expression of metallothionein genes (Mt1, Mt2, Mt3) and zinc transporter genes (Zip1, Zip8) in liver tissue was determined by real-time PCR using specific primers, SYBR Green intercalating dye, and the reference gene Gapdh. Serum activity of AST, ALT, ALP, and LDH was measured; statistical analysis was performed using IBM SPSS Statistics 21 software with one-way ANOVA at a critical significance level of p=0,05. Results. In our study, chronic aluminum exposure was associated with an increase in Zip1 gene expression in the liver, whereas continuous administration of the oxidized pectin-oxymethyluracil complex normalized its expression to control levels. The expression of Zip8 and metallothionein genes (Mt1a, Mt2a, Mt3a) did not change significantly among the experimental groups. At the biochemical level, this complex, when used preventively, contributed to a reduction in AST and LDH activity. Conclusion. The oxidized pectin-oxymethyluracil complex in a rat model of chronic aluminum hydroxide exposure normalizes Zip1 gene expression and reduces AST and LDH activity. Further studies using an expanded set of morphological and molecular markers are required to clarify the organoprotective mechanisms of the complex.

Background : Microplastic particles (MPs) are ubiquitous detected in the environment and have been shown to accumulate in animal and human tissues, inducing oxidative stress, inflammation, and other toxic effects. The accuracy of assessing their organ-specific distribution remains limited: highly sensitive spectroscopic techniques are expensive and labor-intensive, while visual histology is subjective. Objective: To develop and validate software for the automated quantitative assessment of microplastic particles in biological tissues using computer vision methods. Materials and methods : Experimental validation was conducted on biological samples obtained from laboratory animals exposed to polystyrene microplastic particles measuring of 100, 500 and 1000 nm. Microphotographs were processed using an EGFP filter set. The results of the development and validation of software for the quantitative assessment of microplastic particles in the tissue of experimental animals are presented, implemented using the OpenCV, NumPy and Tkinter libraries in Python 3.10. Results: The obtained quantitative data demonstrate that following a single systemic administration, polystyrene particles with diameters of 100, 500, and 1000 nm accumulate in the renal parenchyma, with deposition patterns dependent on their geometric parameters. The highest number of individual particles was observed in the 100 and 1000 nm groups, whereas the maximum density of conglomerates was found in the 500 nm fraction. Conclusions : The developed software provides flexibility through adjustable image processing parameters, making it applicable to various types of biological samples. The obtained data confirm the effectiveness of the proposed approach, which minimizes the influence of the human factor and enables standardization of the analysis process.

Introduction. The ovaries are among the key organs of the female reproductive system, responsible for oocyte formation and maturation, as well as the synthesis of sex hormones. Disruptions in these processes, caused by various environmental contaminants, can lead to a range of pathological conditions. Assessing the distribution of plastic microparticles of different sizes is thus critically important for predicting potential reproductive health risks in women.The aim of our study. To determine and compare the characteristics of accumulation of plastic microparticle (100, 500, and 1000 nm) in the ovaries of female Wistar rats following acute systemic administration, using a specially developed software for automated quantitative analysis of fluorescent images.Material and methods. Twelve female Wistar rats were divided into four groups; each group received an intracardiac injection of a 0.5 mL suspension of fluorescent polystyrene microparticles (MP) with diameters: 100, 500, and 1000 nm) or saline (control). Accumulation of microplastic in ovarian tissue was evaluated by fluorescent microscopy with a descriptive approach and a software designed for quantitative assessment of microparticles and their conglomerates. Data were analyzed using the Bootstrap method with Holm–Bonferroni correction; differences were considered significant at p < 0.05.Results. Only occasional background signals were registered in the control group. All experimental groups demonstrated a significant increase in both the number and total area of microparticles compared to control (p < 0.05), with the highest overall accumulation found in the “MP 1000” group. Smaller particles (100 nm) displayed a pronounced tendency to form large conglomerates, whereas 1000 nm particles were primarily present as individual deposits.Limitations. The investigation was limited to examining the distribution of three sizes of plastic MP within a single experimental series and a single animal species (laboratory rats), without accounting for the estrous cycle phase.Conclusion. Even a short-term exposure to plastic MP can result in their accumulation in ovarian tissue, with the location pattern and the likelihood of conglomerate formation depending on the particle size.Compliance with ethical standards. All experiments in this study were conducted in accordance with European Convention standards for the protection of vertebrate animals used for research and other scientific purposes. The study protocol was approved by the local ethics committee (Approval No. 01-02 from February 8, 2024).Contribution: Ryabova Yu.V. – research concept and design, writing the text, preparing figures; Muhammadieva G.F. – conducting the experiment, scientific editing of the text; Valova Ya.V. – research concept and design, data collection and processing; Khmel A.O. – conducting the experiment, data collection and processing; Repina E.F. – research concept and design; Karimov D.O. – research concept and design; Ahmadeev A.R., Khusnutdinova N.Yu., Kudoyarov E.R. – conducting the experiment. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.Conflict of interest. The authors declare no conflict of interest.Funding. The study was carried out within the framework of the sectoral research program of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing for 2021–2025.Received: April 4, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Introduction. Chronic stress and paracetamol exposure are among the most relevant factors affecting neurochemical and molecular processes in the brain in modern humans. Excessive activation of inflammatory and oxidative pathways during chronic psychosocial stress can lead to a decrease in the expression of neuroprotective and antioxidant genes, exacerbating the neurotoxic effects of drugs such as paracetamol.Objective. To assess the effect of chronic unpredictable stress and oral administration of paracetamol, as well as their combined effect on the morphological state of the brain and on the expression of genes of the antioxidant system and neurotrophic factor in the hippocampus in rats.Materials and methods. The experiment was conducted on forty eight rats (males and females in equal numbers), divided into four groups: control, chronic stress, paracetamol, combined exposure to stress and paracetamol. A complex of various stressors was used to model chronic stress. Paracetamol was administered orally at a dose of 1000 mg/kg. The morphological state of the hippocampus was assessed histologically, gene expression - by quantitative real-time PCR. Statistical analysis included bootstrapping and correction for multiple comparisons using the Holm-Bonferroni method.Results. Macroscopic and histological examination of the rat brain showed the preservation of the normal anatomical structure and integrity of the hippocampal tissues in all groups. Statistical analysis of gene expression showed animals treated with paracetamol (groups III and IV) to show a significant decrease in the mRNA levels in the Sod1 and Bdnf genes in the hippocampus compared to the control and the group exposed to stress only (group II). The expression level of Sod1 and Bdnf was significantly lower in both males and females in these groups (p = 0.001). For the Hmox1 gene, a significant decrease in expression was found only in males in the paracetamol-treated group, while no changes were noted in females.Limitations. Laboratory animals of the same biological species were used for the experiment, and the toxicant was used in only one concentration.Conclusion. Thus, paracetamol, both in isolated use and in combination with chronic stress, has a more pronounced inhibitory effect on the expression of key genes of antioxidant protection and neurotrophic support than stress alone.Compliance with ethical standards. Date of the meeting of the bioethics commission of theUfa Research Institute of Occupational Medicine and Human Ecology dated 02/08/2024 No. 01–02. Throughout the study, the animals were kept in standard conditions with 12-hour artificial lighting during the daytime, a relatively constant level of humidity (30–70%) and an air temperature of 20–25 °C. All animal manipulations were carried out in strict compliance with the rules prescribed in the basic regulatory documents, including the European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes (Strasbourg, 1986) and the Helsinki Declaration on the Humane Treatment of Animals.Contributions: Gizatullina A.A. – concept and study design, material collection and processing, statistical analysis, manuscript writing; Valova Ya.V. – material collection and processing, statistical analysis; Mukhamadieva G.F. – editing; Karimov D.O. – concept and study design, statistical analysis; Karimov D.D. – material collection and processing; Ryabova Yu.V. – material collection and processing; Khusnutdinova N.Yu. – material collection and processing; Khmel A.O. – material collection and processing. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.Conflict of interest. The authors declare no conflict of interest.Funding. Industry research program of Rospotrebnadzor for 2021–2025 “Scientific substantiation of the national system for ensuring sanitary and epidemiological welfare, managing health risks and improving the quality of life of the population of Russia”, on the topic: 6.9.1.2 “Study of the impact of chemical production factors under conditions of chronic stress” No. NIOKTR I124021200153-3.Received: April 30, 2025 / Revised: July 9, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Introduction. In conditions of high chemical load and the increasing prevalence of neurodegenerative diseases, it seems relevant to study the effect of the most common food additives on cognitive functions.The aim is to study the effect of increased doses of sodium benzoate, potassium sorbate, and ascorbic acid on the cognitive functions in white laboratory rats in a rectangular maze, taking into account the ability of the animal’s body to recover after exposure to this mixture.Materials and methods. The study of changes in the chemical composition of the brain under the influence of a mixture of food additives at different dose levels by capillary electrophoresis was carried out in a series of experiments using laboratory mice; rats were used to assess changes in cognitive function under the influence of a mixture of food additives. For statistical processing of the obtained data, the IBM SPSS Statistics 21 package was used. Comparison of groups was carried out using one-way variance analysis.Results. Dietary supplements have been shown to affect the chemical composition of the brain in mice by altering the concentrations of ascorbic (AA), sorbic (SA) and benzoic acids (BA). An increase in the concentration of AA in the brain was observed in all groups receiving additives, especially on day 30 of the experiment. The maximum concentration of SA was recorded at different time points of the experiment (day 5, day 12) depending on the dose of preservatives. An increased content of BA was shown on day 12 of the experiment. During the initial training phase, the supplement mixture improved the rats’ cognitive performance, reducing maze time in both sexes. On day 8, differences in the speed of completing the maze were noted between females and males (p=0.026). After the recovery stage, a deterioration in performance was recorded in both sexes, but more pronounced in females. On day 13, the best results in completing the maze were recorded in female rats.Limitations. The study was conducted once on two types of laboratory rodents. The results obtained on rats and mice cannot always be directly transferred to humans.Conclusions. Changes in the chemical composition of the brain in animals were observed by the 30th day of the experiment, which indirectly correlates with some changes in cognitive functions. A neuroprotective effect of ascorbic acid is assumed, but further studies are needed to clarify the potential mechanism of the processes.Compliance with ethical standards. Date of the meeting of the bioethics commission of the Ufa Research Institute of Occupational Medicine and Human Ecology 02. 08.2024 No. 01-02. The studies were carried out in accordance with the European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes (ETS N 123), Directive of the European Parliament and of the Council of the European Union 2010/63/EU of 09.22.2010 on the protection of animals used for scientific purposes.Contribution: Smolyankin D.A., Ryabova Yu.V. ‒ study concept and design, collection and processing of materials, statistical processing of data, writing, editing; Khusnutdinova N.Yu., Repina E.F., Valova Ya.V., Yakupova T.G., Khmel A.O. ‒ collection and processing of materials, editing; Kurilov M.V. ‒ collection and processing of materials, statistical processing of data, editing; Karimov D.O. ‒ study concept and design, statistical processing of data, writing, editing; Karimov D.D. ‒ collection and processing of materials, statistical processing of data; Akhmadeev A.R. ‒ collection and processing of material. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.Conflict of interest. The authors declare no conflict of interest.Funding. The work was carried out using funds from a subsidy for the implementation of a state assignment within the framework of the industry research program of Rospotrebnadzor for 2021–2025. “Scientific substantiation of the national system for ensuring sanitary and epidemiological well-being, managing health risks and improving the quality of life of the population of Russia”, paragraph 6.1.8 “Scientific substantiation of approaches to assessing the toxic effect of xenobiotics based on cellular technologies and model objects”, registration number: 121062100058-8.Received: February 2, 2025 / Accepted: June 26, 2025 / Published: March 13, 2026

Introduction. Acrylamide is widely used in various industries and is recognized as a toxic compound. Considering the potential risks of its entry into the human body, further research is required to understand the mechanisms of its toxicity and to develop effective approaches for correcting pathological conditions caused by its exposure.The purpose of the study was to evaluate changes in the morphofunctional state of the liver under the influence of acrylamide and correction with oxymethyluracil complexes in dynamics, based on biochemical, genetic and morphological parameters.Material and methods. The experimental study was conducted on outbred male rats, which were administered acrylamide intragastrically at a dose of 5 mg/kg body weight over three months. Preventive correction was performed using oxymethyluracil complexes. Biochemical, genetic, and morphological studies were performed.Results. The studies revealed that after 1.5 and 3 months, the activity of hepatic enzymes significantly increased, and minor changes were observed in the liver parenchyma. The expression of glutathione system genes decreased mid-experiment and increased by the end. Oxymethyluracil complexes demonstrated a certain hepatoprotective effect.Limitations. For a deeper study of this problem, it is necessary to consider the effect of different dosages of the hepatotoxicant and the protective effectiveness of compounds in other modes of exposure to the body.Conclusion. Long-term exposure to acrylamide at a dose of 5 mg/kg body weight had a hepatotoxic effect, manifested by increased activity of cytolysis marker enzymes, bidirectional changes in the expression of genes involved in detoxification processes depending on exposure duration, and, to a lesser extent, histological changes in organ structure. Complex compounds of oxymethyluracil exhibited hepatoprotective effects, with their corrective efficiency ranked as follows: MG-10 > MG-2 > MG-1.Compliance with ethical standards. The study was approved by the Bioethical Commission of the Ufa Research Institute of Occupational Medicine and Human Ecology (Protocol No. 01-10 dated 09.10.2024).Authors’ contribution: Khusnutdinova N.Yu. – conducting research, collecting and processing material, writing text; Ryabova Yu.V. – material processing, text writing; editing; Yakupova T.G. – conducting research, data collection and processing, statistical analysis; Karimov D.O. – research concept and design, editing; Smolyankin D.A., Akhmadeev A.R., Khmel A.O. – data collection and processing, statistical analysis; Repina E.F. – data collection and processing, editing. All co-authors – approval of the final version of the article, responsibility for the integrity of all parts of the article.Acknowledgments. The authors express their gratitude to Alfiya Raisovna Gimadieva A.R., Candidate of Chemical Sciences, Senior Researcher at the Laboratory of Pharmacophore Cyclic Systems of the Ufa Institute of Chemistry, Ufa Federal Research Center of the Russian Academy of Sciences, for the development and synthesis of oxymethyluracil complexes.Conflict of interests. The authors declare no apparent and potential conflicts of interest in relation to the publication of this article.Funding. The work was carried out as part of the state assignment for the industry research program of Rospotrebnadzor “Scientific substantiation of the national system for ensuring sanitary and epidemiological welfare, managing health risks and improving the quality of life of the population of Russia” for 2021-2025, (clause 6.1.8), state registration number 121062100058-8. The synthesis of complex compounds of oxymethyluracil was carried out in accordance with the research plan of the Ufa Institute of Chemistry of the Ufa Federal Research Center of the Russian Academy of Sciences (State Registration Number AAAA-A19-119011790021-4).Received: May 24, 2025 / Revised: June 22, 2025 / Accepted: November 25, 2025 / Published: January 15, 202

Introduction. Thioacetamide belongs to highly toxic compounds that cause significant pathological changes in organs and tissues. In the context of the widespread use of chemicals, the search for effective methods of protecting the body from their negative effects remains an urgent task. The most promising strategy is the development of methods to reduce toxic damage to the body as a result of exposure to chemicals.Material and methods. The study was performed on 56 outbred male rats in a chronic experiment lasting 100 days with an intermediate study of morphological parameters on the 50th day. The animals were divided into 4 groups (2 control and 2 experimental): rats of the second (positive control), third and fourth groups were administered thioacetamide intraperitoneally twice a week at a dose of 50 mg / kg of body weight. The first group of rats (negative control) was administered an equivalent volume of physiological solution in a similar way. One hour before the toxicant, the third experimental group was administered the comparison drug ademetionine at a dose of 25 mg / kg of body weight, the fourth – a complex compound of oxymethyluracil with acetylcysteine at a dose of 500 mg / kg of body weight. The effectiveness of the correction was assessed by pathomorphological changes in the kidneys of rats.Results. In the middle of the experiment, no pathological changes were found in the kidneys of rats of all the studied groups. By the end of the experiment, under the influence of thioacetamide, signs of damage to the renal parenchyma were observed in the form of granular dystrophy, swelling of the cytoplasm of epithelial cells, narrowing of the lumen of the tubules and the formation of protein inclusions. When corrected with a complex compound of oxymethyluracil with acetylcysteine, pathological changes in the kidneys were less pronounced. Morphometric analysis of the cross-sectional area of ​​the proximal tubules and the area of ​​the cell nuclei confirmed the results of histological studies by groups.Limitations. With long-term exposure to thioacetamide, the hepatoprotective efficacy of drugs was assessed primarily by morphological characteristics, but for a more comprehensive assessment of the correction of toxic effects, it is also necessary to take into account biochemical and functional indicators.Conclusion. Chronic administration of thioacetamide to rats at a dose of 50 mg/kg body weight has a nephrotoxic effect, which is reduced by prophylactic administration of ademetionine and a complex compound of oxymethyluracil with acetylcysteine ​​to animals. According to pathomorphological signs, the effectiveness of the nephroprotective effect of the complex compound of oxymethyluracil with acetylcysteine ​​is higher than that of ademetionine.Compliance with ethical standards. The study was approved by the bioethics committee of the Ufa Research Institute of Occupational Medicine and Human Ecology (protocol No. 01-02 dated 08.02.2024).Authors’ contribution: Khmel A.O. – collecting and processing material, writing text; Yakupova T.G., Muhammadieva G.F., Gizatullina A.A., Khusnutdinova N.Yu. – collecting and processing material; Ryabova Yu.V., Repina E.F. – editing; Karimov D.O. – research concept and design, statistical analysis. All co-authors — approval of the final version of the article, responsibility for the integrity of all parts of the article.Conflict of interests. The authors declare no apparent and potential conflicts of interest in relation to the publication of this article.Funding. The work was carried out as part of the state assignment for the industry research program of Rospotrebnadzor “Scientific justification of the national system for ensuring sanitary and epidemiological well-being, managing health risks and improving the quality of life of the population of Russia” for 2021-2025. clause 6.1.8, state no. registration 121062100058-8. Received: April 2, 2025 / Revised: May 5, 2025 / Accepted: November 25, 2025 / Published: January 15, 2026

Evaluation of rat behavior in experimental studies is important for understanding neurophysiological and psychopharmacological processes. The aim of this study is to investigate the effect of paracetamol on the behavioral responses of laboratory rats under chronic stress. Four groups of white outbred rats (N=48) were formed within the framework of the study. For statistical analysis of the data, specialized IBM SPSS Statistics version 21 software was used. The normality of distribution was checked using the Kolmogorov-Smirnov criterion. The data were then evaluated using one-way analysis of variance (ANOVA), with Tukey and Tamhane criteria used for multiple comparisons. The focus is on assessing changes in the cognitive and emotional spheres of animal behavior, as well as analyzing the possible neuroprotective properties of paracetamol under long-term stress exposure. This article describes changes in the behavioral responses of animals from different groups to objectively assess the effect of the drug on the levels of anxiety, depression, aggression and cognitive functions in rats under chronic stress. The behavior of rats on a board with holes, in a cage for measuring activity, in the Open Field and Elevated Plus Maze tests during a four-week study against the background of taking an aqueous solution of paracetamol is described. The results of this study confirm the hypothesis that the combination of stress and paracetamol intake has a significant effect on the behavioral activity of laboratory rats. This is manifested in a decrease in vertical and horizontal activity, changes in behavior in the elevated plus maze and a decrease in mobility in the open field. The obtained data can serve as a basis for further studies of the mechanisms of interaction between stress and pharmacological drugs on the central nervous system of animals.