Introduction. The World Health Organization considers sensitizing effects to be effects that require close attention, especially in terms of research and regulation, due to the high allergenic background among the population, including the Russian Federation. The allergic effect of chemicals is taken into account when organizing the workflow, conducting a special assessment of working conditions, preliminary and periodic medical examinations of employees, etc. Many hygienic standards for substances in the air of the work area were justified in the 50s and 80s. of the last century and may not fully reflect the real picture of the danger. Currently, the international community has developed new approaches to testing, assessing and classifying the hazards of chemicals by sensitizing effects, and therefore the regulatory and methodological framework of the Russian Federation also requires updating.

The study aims to harmonize domestic and foreign approaches to the study and assessment of exposure and to develop a national list of chemicals that cause sensitization of the skin and/or respiratory tract, classified in accordance with the Globally Harmonized System of Hazard Classification and Labelling of Chemical Products (GHS).

Materials and methods. The experts have analyzed national and international approaches to the assessment, classification of hazards and regulation of chemicals with sensitizing effects; documents from United Nations agencies, scientific articles, monographs, information from official national and foreign databases on sensitizing effects.

Results. The article presents a phasing scheme for conducting a study on the study of sensitizing effects, in which in vivo methods are a priority. The harmonization of international approaches to the assessment of the GHS effect with domestic experimental practice has been carried out. A national list of chemicals with sensitizing effects has been formed, which includes 1186 names, of which 928 are skin sensitizers, 23 are respiratory, and 235 are substances with both skin and respiratory sensitization. The necessity of developing and (or) updating hygienic standards in the air of the working area, taking into account this type of exposure, is indicated.

Limitations. The national list of chemicals with sensitizing effects, developed on the basis of the results of experimental studies presented in open sources of information, is not exhaustive.

Conclusion. The authors have carried out the harmonization of domestic and foreign approaches to the study and assessment of the sensitizing effects of chemicals in order to update the regulatory and methodological bases of the Russian Federation. Scientists have proposed a classification of the dangers of skin sensitizers in accordance with the GHS using in vivo research methods introduced into the practice of domestic toxicology. They have compiled a national list of chemicals that cause sensitization of the skin and/or respiratory organs, which can be used to identify substances that are a priority for regulating the content in the air of the work area, and update existing regulations taking into account this type of exposure.

Ethics. The study does not require an opinion from the Bioethics Commission.

Contributions:
Khamidulina H.H. — concept and design of research, collection and processing of material, writing and editing of text;
Tarasova E.V. — concept and design of research, collection and processing of material, writing and editing of text;
Dorofeeva E.V. — writing and editing text;
Zamkova I.V. — writing and editing text;
Proskurina A.S. — writing and editing text;
Rabikova D.N. — writing and editing text;
Nazarenko A.K. — writing and editing text;
Lastovetsky M.L. — writing and editing text;
Araslanov I.N. — writing and editing text;
Aniskova Yu.Y. — writing and editing text;
Balashov P.E. — writing and editing text.

Funding. The study was carried out as part of the research project "Validation of alternative research methods in assessing the hazards and risks of exposure to chemicals on human health as a tool for regulating the safety of a chemical factor".

Conflict of interest. The authors declare no conflict of interest.

Received: 02.12.2025 / Accepted: 10.12.2025 / Published: 20.12.2025

Introduction. Cardiovascular diseases remain one of the leading causes of morbidity and mortality in the world and in the Russian Federation, which makes the problem of prevention and early detection of cardiovascular pathology a priority task of medicine. Despite significant advances in diagnosis and treatment, methods of functional assessment of the state of the body's regulatory systems are becoming particularly relevant, capable of detecting preclinical signs of disorders of the body's adaptive reserves and predicting the likelihood of developing cardiovascular diseases.

The study aims to assess the general state of regulatory systems and the level of functional reserves of the body in medical workers before and after COVID-19 infection in order to identify hidden forms of cardiovascular maladaptation based on the calculation of cardiorespiratory indices.

Materials and methods. The authors conducted a cross-epidemiological study, during which they analyzed the prevalence of chronic non-communicable diseases, working conditions and cardiorespiratory indices (Kerdo vegetative index, Myznikov index, Kvaas index, Robinson index, blood circulation efficiency coefficient and type of circulatory self-regulation) among medical workers of the regional clinical hospital before and three years after infection with COVID-19.

Experts analyzed 368 medical records of women aged 30 to 62 years, and formed groups depending on working conditions, qualifications and presence of cardiovascular diseases before COVID-19. A set of informative and significant cardiorespiratory indices in the development of hypertension has been identified, on the basis of which a prognostic model has been developed.

Results. The scientists have developed a regression model to determine the risk of hypertension based on the calculation of cardiorespiratory parameters (Myznikov index, Robinson index, blood circulation efficiency coefficient), taking into account age. If a value equal to or greater than the threshold value of 0.401 is obtained, the healthcare professional has a high risk of developing hypertension within three years. The sensitivity and specificity of the obtained predictive model are 90.5% and 90.6%, respectively.

Limitations. The study is limited by the number of people surveyed (368 people), profession, and follow-up period.

Conclusion. The developed prognostic model can be used in a comprehensive assessment of the risk of hypertension among medical workers who have suffered COVID-19.

Ethics. The study was conducted in accordance with Ethical standards and approved by the local Ethics Committee of the Izmerov Research Institute of Occupational Health in accordance with the established procedure (Protocol No. 8 of 2022). Voluntary informed consent was obtained from each participant included in the study.

Contributions:
Kuzmina L.P. — research concept and design, editing;
Osmanova P.S. — research concept and design, data collection and processing, text writing, editing;
Anokhin N.N. — research concept and design, text writing, editing;
Kislyakova A.A. — research concept and design, text writing, editing.

Funding. The study had no funding.

Conflict of interest. The authors declare no conflict of interest.

Received: 27.11.2025 / Accepted: 08.12.2025 / Published: 20.12.2025

Introduction. The problem of the high prevalence of cardiovascular diseases and related complications, leading to a decrease in working capacity and disability in working currently remains urgent. A wide variety of etiological factors are known to influence the development of chronic heart failure, one of which is a change in the autonomic regulation of the heart, and therefore the analysis of heart rate variability has proven to be an informative method for assessing the risk of developing cardiovascular complications.

The study aims to evaluate changes in heart rate variability among workers in the main professions of the coal industry with signs of diastolic dysfunction of the left ventricle.

Materials and methods. 87 employees of the main professions of the coal industry participated in the study. Ultrasound examination of the heart was performed according to generally accepted methods on a Vivid E9 ultrasound scanner. The researchers conducted an analysis of heart rate variability with the allocation of spectral and nonlinear indicators at rest and during psychoemotional stress.

Results. All the examined patients had a normal geometry and a preserved left ventricular ejection fraction. During the examination, the authors revealed diastolic dysfunction of the left ventricle in 44% of the surveyed miners in the absence of cardiovascular diseases. In miners with diastolic dysfunction, a decrease in the spectral index of high frequency was revealed, reflecting the influence of the parasympathetic division of the autonomic system. Correlation analysis confirmed the association of parasympathetic tone with myocardial relaxation in diastole. In all the surveyed miners, the authors found an increased sympathetic effect on the cardiovascular system and a decrease in adaptive capacity to stress.

Limitations. This study is limited to a sample of workers in the main professions of the coal industry without cardiovascular diseases.

Conclusion. Sympathetic activation and a decrease in parasympathetic effect on the heart, leading to dysfunction of myocardial microcirculation, changes in metabolism and apoptosis of cardiomyocytes, contribute to the formation of diastolic dysfunction of the left ventricle in workers of the main professions of the coal industry.

Ethics. The study was conducted in compliance with the standards of the Bioethical Committee of the Research Institute for Complex Problems of Hygiene and Occupational Diseases (Minutes of meeting No. 3, § 1 dated November 17, 2022), developed in accordance with the Helsinki Declaration of the World Medical Association (ed. 2013). The subjects signed an informed consent to participate in the study.

Contributions:
Martynov I.D. — data collection and processing, writing the text;
Korotenko O.Yu. — research concept and design, data collection and processing, literary data collection, text writing;
Filimonov E.S. — data collection and processing, editing.

Funding. The study had no funding.

Conflict of interest. The authors declare no conflict of interest.

Received: 06.11.2025 / Accepted: 03.12.2025 / Published: 20.12.2025

Introduction. In recent decades, the incidence of malignant neoplasms in the world has increased significantly, and environmental factors make a significant contribution to this growth. Anthropogenic air pollution is one of the most serious threats to public health worldwide. It contributes to the development of various respiratory diseases, including carcinogenesis. Currently, the experts are registering annually in the Russian Federation more than 450,000 newly diagnosed cases of malignant neoplasms.

The study aims to assess the risk of developing malignant neoplasms with inhaled carcinogens in children and adults in Nizhny Novgorod.

Materials and methods. The authors have carried out the carcinogenic risk assessment in accordance with R 2.1.10.3968-23 "Guidelines for assessing the risk to public health when exposed to chemicals that pollute the environment". Information on the concentrations of pollutants in the atmospheric air was obtained from the Verkhne-Volzhskoye UGMS. Statistical data on the morbidity of the Nizhny Novgorod population were taken from the collection "Basic indicators of public health and the activities of public medical organizations in the Nizhny Novgorod region for 2023".

Results. When assessing population risks based on data from 2023, the scientists have established that elevated concentrations of formaldehyde in the atmospheric air of Nizhny Novgorod can provoke 9 and 70 additional cases of malignant neoplasms, benzene — 6 and 64, and ethylbenzene — 3 and 9 additional cases for children and adults, respectively. Simultaneous exposure to these carcinogens will lead to 15 additional cases of cancer per year among children and 143 among adults.

Conclusion. The individual carcinogenic risk to the health of the Nizhny Novgorod population from inhaled exposure to pollutants is represented at medium (for the adult population) and low (for children) levels. However, the results of calculating the lifetime population carcinogenic risk are worrisome, which requires constant medical monitoring and systematic measures to reduce carcinogenic substances in urban air.

Ethics. This study did not require the conclusion of an Ethics Committee.

Contributions:
Bolshakova A.D. — research concept and design, material collection and processing, statistical data processing, text writing;
Zaznobina N.I. — material processing, statistical data processing, text writing, editing;
Kalashnikov I.N. — editing;
Yashanova M.I. — editing.

Funding. The study had no funding.

Conflict of interest. The authors declare no conflict of interest.

Received: 09.06.2025 / Accepted: 04.12.2025 / Published: 20.12.2025

Introduction. For the first time, researchers performed optical coherence tomography with retinal angiography (OCTA) in pilots, and they also performed a correlation analysis of OCTA results with the pilot's age and flight load.

The study aims to research the condition of the retina based on the results of OCTA in the studied group of pilots in correlation with age and flight load.

Materials and methods. The main group of the study consisted of 120 pilots in the age range of 24–45 years, whose total flight time ranged from 52 to 1600 hours. The authors divided this group into 2 subgroups depending on the flight load (no more than 60 hours per year and more than 60 hours per year). The control group consisted of 79 men aged 24 to 45 years, whose professional activity is not associated with extreme types of work. To analyze the morphometric state of retinal ganglion cells, scientists divided the main and control groups into 3 age subgroups (24–30, 31–35, 35–45 years). The results of OCTA were evaluated based on the results of examination of each eye. The scientists have performed morphological structural analysis of the areas of the central, paracentral retina and optic disc using the OCTA protocols "ONH", "RNFL", "3D Disk" and "GCC". The state of the blood supply to the retina was assessed according to the OCTA protocols "ND Angio Retina", "HD Angio Disk 4.4", "Fovea Density". The authors have conducted a statistical analysis using StatTech software version 3.1.8 (developed by Stattech LLC, Russia). "Statistics 10".

The comparison of the two quantitative groups with a normal distribution, provided that the variances were equal, was carried out using the Student's t-test, and with unequal variances, using the Welch t-test.

The comparison of the two groups by a quantitative indicator, the distribution of which differed from the normal one, was performed using the Mann-Whitney U-test.

Results. The analysis of optical coherence tomography of the retina in pilots for the first time revealed morphometric destruction (the presence of acquired increased curvature of retinal vessels, areas of reduced blood supply, local destruction of pigment epithelium, the presence of areas of retinal disorganization (DRIL)) in a certain percentage of cases, which was not related to flight load or age. These changes in pilots can be both a consequence of chronic stress and the result of hypoxia during flight.

The analysis of the blood flow status of the central and paracentral retinal zones revealed a statistically significant decrease in blood flow levels according to the indicator: Fovea VD (Vessel Density) in 70% of the pilots, where increased vascular tortuosity was diagnosed compared with the control group (p>0.001).

An analysis of the morphometric status of retinal ganglion cells in pilots based on the results of the evaluation of the OKTA "GCC" protocol revealed a significant difference in the GLV% indicator (global ganglion cell losses) compared with the control group.

Limitations. The study has professional (pilots) and gender (men) limitations. Persons with ophthalmological pathology and with an ametropia of more than 3.0 diopters are also excluded.

Conclusion. The changes in the morphofunctional state of the retina in pilots revealed by the results of optical coherence tomography reflect the individual characteristics of adaptation to extreme factors of flight load.

Morphological destructions of the retina, such as the presence of acquired increased curvature of retinal vessels, areas of reduced blood supply, local destruction of the pigment epithelium, and the presence of areas of retinal disorganization (DRIL) may indicate a decrease in the activity of autoregulatory adaptation mechanisms both at the retinal and central nervous system levels. An increase in the OCTA index (GLV%) in pilots in the age group of 25–30 years may indicate a decrease in the functional activity of the central nervous system due to stress response factors.

Ethics. The study was conducted in compliance with Ethical principles. All subjects signed a voluntary informed consent to participate in the study in accordance with the Helsinki Declaration of the World Medical Association "Ethical Principles of conducting scientific medical research involving humans as subjects." The study was approved by the local Ethics Committee of the N.N. Burdenko State Medical University (Protocol No. 262 dated 04/26/2022).

Contributions:
Podyanov D.A. — concept and design of research, collection and processing of material, final editing;
Gracheva M.A. — collection and processing of material, statistical data processing, text editing;
Kazakova A.A. — collection and processing of material;
Osetsky N.Y. — collection and processing of material, statistical data processing;
Koneva D.A. — collection and processing of material, statistical data processing;
Fomin A.V. — collection and processing of material;
Manko O.M. — research concept and design, material processing, text writing, editing.

Funding. The funding was provided as part of a research project (R&D RAS FVFR-2024-0034 (1023022700092-0-3.1.4.; 1.9; 5.1.1)).

Conflict of interest. The authors declare no conflict of interest.

Received: 01.11.2025 / Accepted: 14.11.2025 / Published: 20.12.2025

Introduction. Numerous studies demonstrate the impact of harmful occupational factors on the immune system. While these changes are adaptive in the initial stages, prolonged exposure can lead to the development of maladaptive processes, leading to functional impairment of immune cells, which can contribute to the development of pathology.

The study aims to analyze patterns of changes in immune status indicators in workers engaged in the enrichment of iron-containing ores.

Materials and methods. The main group consisted of 95 workers employed at an iron ore beneficiation plant (exposed to occupational factors: crystalline silicon dioxide (class 3.1/3.2), noise (class 3.1/3.2/3.3), general vibration (class 2/3.1), and workload severity (class 3.1)). The comparison group consisted of 85 workers in repair and maintenance occupations (workload severity (class 3.1/3.2)).

The study measured levels of immunoglobulins A, M, G, C3, and C4 complement components, interleukins (IL) 1β, 6, 8, 10, and 18, tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), and interferon gamma (IFN-γ).

Results. The workers of the main group had significantly (p<0.05) lower levels of C3 and C4 complement components, IL‑1β, IL-6, IL-10, TNF-α and higher levels of IgG, IL-18, MCP-1, IFN-γ, more often (p=0.017) the levels of IgM below the reference values were observed — in 13.7% than in the comparison group. An increase in the levels of interleukins with work experience was shown: IL-18 in the main group, IL-6 - in both the main and comparison groups. The workers of the main group showed a decrease in IL-10, IFN-γ and an increase in MCP-1 with an increase in the aerosol concentration and an increase in IL-6 and IFN-γ with an increase in the noise level. In the main group, associations of smoking and obesity with the levels of immunoglobulins and proinflammatory cytokines were found.

Limitations. The study is limited to a sample of the surveyed from one mining and processing plant.

Conclusions. The results obtained demonstrate the influence of exposure to a complex of occupational factors at an iron ore enrichment plant on changes in the immune status of workers, which determines the importance of identifying informative immunological indicators for in-depth employee examination to assess the severity of changes.

Ethics. The study was conducted in compliance with Ethical standards for conducting medical research involving humans in accordance with the requirements of the Helsinki Declaration of the World Medical Association. The study was approved by the conclusion of the local Ethics Committee of the Izmerov Research Institute of Occupational Health (protocol of meeting No. 5 dated 08/02/2023).

Contribution:
Khotuleva A.G. — collection of material, data processing, laboratory research, writing, editing;
Kuzmina L.P. — research concept and design, editing;
Khokhlova O.V. — collecting material, data processing, conducting laboratory tests, writing text;
Kolyaskina M.M. — collecting material, conducting laboratory research, editing;
Kislyakova A.A. — collecting material, conducting laboratory research, editing.

Funding. The study had no funding.

Conflict of interests. The authors declare no conflict of interest.

Received: 01.12.2025 / Accepted: 03.12.2025 / Published: 20.12.2025

Currently, the study of the work of medical workers is extremely relevant, while the study of burnout syndrome, widespread among people in the medical professions (43.2–76.9%), is of particular importance.

The study is a systematic review conducted in the international scientific citation database PubMed and the national scientific electronic library eLibrary for 2024. 150 articles suitable for analysis were found.

The study aims to summarize and analyze modern research (2024) on psychoemotional disorders and burnout syndrome in medical professionals.

The reason for the formation of burnout syndrome, first of all, is industrial stress, especially in professions with a high level of responsibility. Risk factors for the formation of psychoemotional disorders include both organizational problems and high work intensity of doctors and nurses, as well as personal lifestyle characteristics and unconstructive behaviors in dealing with stress.

Burnout syndrome can form already at the initial stage of training for doctors and nurses, which requires a comprehensive impact on all components of the educational environment, while young age is a significant risk factor for mental health problems.

The manifestations of burnout syndrome are typical for the majority of people who worked in medical organizations during the COVID-19 pandemic: for employees of the "red zone" of the hospital; doctors and paramedical staff at the outpatient clinical level; non-medical staff due to psychoemotional overloads associated with increased responsibility for the organization of the institution's activities and a large amount of work; students-medical professionals facing new challenges related to COVID-19 .

Understanding the mechanisms of burnout syndrome formation and its consequences is necessary to develop effective strategies for helping people with early signs of emotional burnout.

Funding. The study had no funding.

Conflict of interest. The author declares no conflict of interest.

Received: 18.11.2025 / Accepted: 26.11.2025 / Published: 20.12.2025

The work of surgeons is one of the most time-consuming and responsible areas of human activity. The main element of the profession is operational activity, characterized by high physical, mental and social stress. An important feature of the work of a surgeon is a prolonged stay in a forced working position, which, according to modern data, contributes to the development of diseases of the musculoskeletal system and nervous system, such as osteochondrosis, shoulder-scapular periarthrosis and tunnel syndromes. Such diseases can cause disability, a decrease in the quality of life, a reduction in career duration, and a deterioration in the quality of surgical care. Despite the importance of the problem, generally accepted methods for assessing the working posture of surgeons remain insufficiently accurate and comprehensive, which limits the possibilities for developing effective preventive measures.

A review of the literature has been conducted in order to generalize and analyze modern methods of physiological and ergonomic assessment of working posture using the example of surgeons. The publications were searched using bibliographic databases Scopus, MedLine, Web of Science, PubMed, The Cochrane Library, RSCI, Cyberleninka.

The presented data indicate a high prevalence of diseases of the musculoskeletal system among surgeons associated with prolonged exposure to high-risk forced positions, static loads and suboptimal organization of the workspace. Modern methods of physiological and ergonomic assessment of working posture include semi-direct observation methods based on visual analysis and scoring of forced posture on standardized scales, provide effective rapid diagnosis of ergonomic risk. However, these approaches do not allow tracking the dynamics of the load on the neuromuscular apparatus in real time. Direct methods based on the use of inertial measuring devices and wireless surface electromyography allow for objective, high-precision dynamic monitoring of the working posture. They provide registration of kinematic parameters (angles of flexion, extension and deviation of body segments), quantification of muscle activity (by changing the amplitude and frequency characteristics of the signal) and timing of time spent in forced poses, which allows you to stratify ergonomic risk and identify critical movement patterns. In the future, an integrated approach to assessing and optimizing the working posture of surgeons based on a combination of subjective and objective methods will not only improve the health and quality of life of surgeons, but can also increase the effectiveness and safety of surgical interventions.

Funding. The work was carried out within the framework of funds allocated for the implementation of the state task of the East-Siberian Institute of Medical and Ecological Research.

Conflict of interest. The author declares no conflict of interest.

Received: 22.10.2025 / Accepted: 24.11.2025 / Published: 20.12.2025

Introduction. Despite the widespread use of sulfuric acid in industry (acid leaching processes in copper metallurgy, extraction of rare earth elements, production of mineral fertilizers, uranium mining, production of chemical fibers, dyes, smoke-forming and explosives, etc.), there is practically no data in the literature on studies aimed at studying the effect of aerosols containing sulfuric acid vapor on the state of adaptation of workers.

The study aims to explore hormonal, hematological and immune markers to assess the adaptation processes in female workers of the copper smelter.

Materials and methods. The authors examined 54 conditionally healthy employees of the vitriol workshop of a copper smelter who were exposed to an industrial aerosol containing sulfuric acid vapors. The control group consisted of 15 conditionally healthy female workers who did not come into contact with industrial aerosols. All the surveyed are comparable in age and length of service. The experts have determined the type of overall adaptive response using the L.I. Garkavi method, which takes into account the relative number of lymphocytes. The complex of markers included: hormonal, hematological, and immunological parameters.

Results. Experts have revealed higher concentrations of cortisol and thyroid-stimulating hormone in the main group, increased indicators characterizing the body's nonspecific resistance (Harkavi index, immunoreactivity index, and lymphocyte-to monocyte ratio) and inflammation intensity (leukocyte count to erythrocyte sedimentation rate ratio), increased lymphocytes (CD3+25+) involved in differentiation and proliferation of T-lymphocytes. Four types of adaptive reactions were detected in the main and control groups with the same frequency. The researchers have found a significant dependence of cortisol concentration and the immunoreactivity index on the type of adaptation in the main group. During the stress reaction, activation of the cellular link was detected against the background of minimal cortisol levels, minimum values of the Garkavi index and the immunoreactivity index; unlike stress, the Garkavi index was increased during activation and reactivation.

Limitations. The data obtained are specific to a specific group of female copper smelter workers. The methodological approach can be applied to surveys of female workers in other occupational groups.

Conclusions. The results of the study indicate the expediency of studying hormones, immune status, and hematological parameters with the calculation of leukocyte indices as predictors of the effects of sulfuric acid on the body.

Contributions:
Sakhautdinova R.R. — concept, collection and processing of material, writing text;
Roslaya N.A. — research design, text editing;
Bushueva T.V. — writing, editing text;
Panov V.G. — statistical data processing.

Funding. The study had no funding.

Conflict of interest. The authors declare no conflict of interest.

Received: 24.11.2025 / Accepted: 02.12.2025 / Published: 20.12.2025

Introduction. Benzene and phenol are widespread toxins that enter the environment with industrial emissions, being typical representatives of coke production, as well as automobile exhaust and tobacco smoke. Their impact poses risks to public health and especially to industrial workers. The toxicity of these compounds is associated with the induction of oxidative stress, which can cause cell apoptosis. Studying the effects of benzene and phenol on the expression of genes regulating apoptosis in the liver is important for identifying the mechanisms of toxicity and searching for early biomarkers of response.

The study aims to explore changes in the expression of the p53, casp3, and casp9 genes in the liver of laboratory animals exposed to subchronic effects of phenol and/or benzene to clarify the mechanism of their isolated and combined effects.

Materials and methods. The authors conducted an experiment on white female rats, which were divided into 4 groups: "Benzene", "Phenol", "Benzene+Phenol" and "Control", 10 individuals each. The researchers carried out intoxication by intragastric administration 3 times a week for 4 weeks in a single dose of benzene — 100 mg/kg b.w. and phenol 15.85 mg/kg b.w. At the end of the experiment, the authors performed a complete decapitation of the animals and, for the analysis of gene expression, liver fragments were fixed, followed by the isolation of RNA, on the matrix of which cDNA was synthesized. The expression level of the casp3, casp9, and p53 genes was determined by quantitative real-time PCR. The scientists have conducted statistical analysis of the data using the Mann–Whitney U-test in the Statistica (StatSoft) program.

Results. The expression level of the p53 gene was significantly lower by 2.86 times in the "Benzene+Phenol" group of animals compared with the control group (p=0.0095). There was also a tendency to decrease the level of p53 expression in the liver in the group of animals exposed only to benzene, but it did not reach the level of statistical significance (p=0.057). The expression of the casp3 and casp9 genes did not significantly differ between the experimental groups and the control.

Limitations. The study was performed on female Wistar rats without taking into account possible intersex differences.

Conclusion. The combined administration of benzene and phenol suppresses the expression of the p53 gene in the liver of animals without changing the expression of the casp3 and casp9 genes, which may indicate a violation of the p53-dependent pathway of apoptosis. Further studies are needed to clarify the mechanisms of toxicity.

Ethics. Ethics approval was provided by the Ethics Committee of the Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers (protocol No. 2 of January 11, 2024).

Contributions:
Kikot A.M. — collecting material and data processing, writing text;
Bereza I.A. — collecting material and data processing, writing text;
Shaikhova D.R. — collecting material and data processing, writing text;
Sutunkova M.P. — research concept and design, editing;
Minigalieva I.A. — concept and design of research, editing;
Shabardina L.V. — collection of material and data processing, editing.

Funding. The study had no funding.

Conflict of interest. The authors declare no conflict of interest.

Received: 02.10.2025 / Accepted: 02.12.2025 / Published: 20.12.2025