Introduction. Improving the accuracy, effectiveness, and safety of magnetic contrast media for MRI diagnostics is an urgent task for both clinical medicine and researcher. Therefore, the introduction of new innovative drugs opens up additional opportunities for assessing the functional state of organs and tissues, significantly increasing the accuracy of diagnosis and the effectiveness of treatment.Materials and methods. The parameters of acute toxicity, species and sexual sensitivity to an innovative drug containing gadolinium nanoparticles stabilized with arabinogalactane (GD-AH) and a commercial drug for MRI studies, Gadodiamide (a reference drug), were evaluated using the intragastric route of administration in outbred rats of both sexes at a dose of 2000 mg/kg body weight (b.w.). Additionally, acute toxicity assessment for the innovative drug GD-AG was performed with intraperitoneal administration in mice at doses of 2000 and 300 mg/kg b.w.Results. Intragastric administration of Gadodiamide and the innovative Gd-AG nanocomposite to rats of both sexes caused neither the death of animals nor changes in internal organs during macroscopic examination. Intraperitoneal administration of 2000 mg/kg b.w. GD-AG to mice resulted in 100% death. A dose of 300 mg/kg b.w. did not cause death, but macroscopic changes in internal organs were observed.Limitations. The study is limited to studying the acute toxicity parameters of an innovative drug containing gadolinium nanoparticles stabilized with arabinogalactane (GD-AG) and a commercial drug for MRI studies, Gadodiamide.Conclusion. According to the toxicometric parameters of acute toxicity, the average lethal doses for intragastric administration of the commercial drug Gadodiamide and the innovative nanocomposite Gd-AG to rats do not differ from each other and are definted as >2000 mg/kg b.w., which characterizes them as substances with a low risk of acute toxicity (hazard class V). The average lethal dose for the intraperitoneal route of administration of Gd-AG nanocomposite is in the range of 300 mg/kg b.w. < LD50 < 2000 mg/kg b.w., which belongs to the IV class of acute toxicity according to the classification of K.K.Sidorov and is defined as a substance with low toxicity.Compliance with ethical standards. The study was approved by the local Ethics Committee of the FSBSI VSIMEI (Protocol No. 8 dated 12/15/2023), conducted in accordance with the European Convention for the Protection of Vertebrate Animals Used for Experiments or Other Scientific Purposes (ETS N 123), Directive of the European Parliament and of the Council of the European Union 2010/63/EC dated 09/22/2010 on the protection of animals used for scientific purposes.Contribution: Sosedova L.M. – research concept and design, statistical data processing, text writing, editing; Novikov M.A. – data collection and processing, statistical data processing, text writing; Titov E.A. – literary study, data collection and processing, statistical data processing; Pankova A.A. – data collection and processing, statistical data processing; Vokina V.A. – data collection and processing, statistical data processing, text writing; Konkova T.V. – data collection and processing, synthesis of nanocomposite, statistical data processing; Sukhov B.G. – research concept and design, editing. 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 had no sponsorship.Received: July 8, 2025 / Accepted: October 15, 2025 / Published: April 17, 2026

Introduction. Exposure to smoke from natural peat fires during the early postnatal period leads to the development of a wide range of pathological conditions, among which the long-term effects of smoke on the central nervous system (CNS) remain the least studied.Materials and methods. Inhalation exposure of newborn rats to peat smoke was carried out during critical periods of ontogenesis – from the 23rd to the 27th day of life. The CO concentration in the inhalation chambers was 21 (13; 28) mg/m³, and the PM2.5 concentration was 0.09 (0.04; 0.19) mg/m³. At 3 months of age, the functional state of the CNS was assessed in the rats. The examination included open field behavioral testing, EEG recording, and histological examination of the cerebral cortex.Results. Males exhibited a sharp reduction in time spent in the center of the arena and a decrease in the exploratory area, indicating suppression of the active-searching component of behavior. EEG results in males showed a decrease in EEG amplitude characteristics, primarily due to waves in the low-frequency range (delta and theta rhythms). In females, conversely, an increase in amplitude and index was observed, largely due to fast-wave beta rhythm activity. No changes in nervous tissue structure were detected.Limitations. This study is limited to adult sexually mature white rats exposed to peat smoke from 23rd to 27th postnatal day.Conclusion. Exposure to peat smoke in the early postnatal period leads to impairments in species-specific behavior and the amplitude-frequency properties of the total bioelectrical activity of the cerebral cortex in adult sexually mature rats. The most significant shifts in CNS impairment are observed in male white rats.Compliance with ethical standards. The study was approved by the Local Ethics Committee of the East-Siberian Institute of Medical and Ecological Research (Protocol No. 32 dated 01/10/2023) and was conducted in accordance with the European Convention for the Protection of Vertebrate Animals used for Experimental and Other Scientific Purposes (ETS No. 123) and 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.Contributions: Sosedova L.M. – study concept and design, literature review, manuscript writing; Vokina V.A. – study concept and design, experiment conduction, data processing, analysis and interpretation, literature review, manuscript writing; Pankova A.A. – experiment conduction, data collection and primary processing, statistical analysis; Titov E.A. – histological specimen preparation and processing, data processing, statistical analysis; Novikov M.A. – histological specimen preparation and processing, data processing, statistical analysis; Savchenkov M.F. – editing, approval of the final version of the manuscript, responsibility for the integrity of all parts of the manuscript. Conflict of interest. The authors declare no conflict of interest.Funding. The study had no sponsorship.Received: March 24, 2026 / Revised: May 18, 2026 / Accepted: June 18, 2026 / Published: July 31, 2026

Introduction. The lack of information about the health safety of firefighters and those taking part in extinguishing landscape fires from short-term exposure to sublethal concentrations of carbon monoxide determines the relevance of this work. Material and methods. The study on rats used methods for assessing the state of the central nervous system, including behavioral tests, electroencephalography, morphology of the cerebral cortex, cardiac tissue, testes and liver. Chemical research methods included the determination of the content of CO and PM2.5 in the air of the exposure chamber. Genotoxicity on blood cells was determined by the DNA comet method. Results. The experiment showed that exposure to peat smoke with a level of CO=99±2.5 mg/m3 and PM2.5=0.72±0.3 mg/m3 for 30 minutes had no pronounced adverse effect on male rats. The results of studying the motor research behavior of animals, EEG parameters, the structure of cardiomyocytes, epicardium, myocardium and pericardium did not differ from those in control rats. In the tissue of the sensorimotor cortex of the rats of the experimental group, an increase in the number of acts of neuronophagy was revealed, and in the liver tissue – a decrease in the number of polynuclear hepatocytes. In animals exposed to peat smoke, a decrease in the spermatogenesis index was revealed, which demonstrates a violation of the formation of germ cells of the final stages of spermatogenesis. No genotoxic effect was detected. Collectively, the identified changes may indicate a compensatory reaction of the rat body when ingested with toxicants. Conclusion. The toxicity of a multicomponent mixture of forest biomass combustion products with short-term exposure, containing a CO concentration of 100 mg/m3, may be underestimated when predicting long-term effects on the reproductive potential of the adult population. Limitation. It is caused by a number of uncertainties related to insufficient information about the short-term effects of high concentrations of CO and solid particles PM2.5 in the smoke of landscape fires on the nervous, reproductive, genome/epigenome system of male rats.

Introduction. Currently, the problem of wildfires is acquiring a global scale, and in the conditions of climate change, their further increase is predicted. The constant increase in the scale of wildfires and long-term annual smoke pollution of vast territories dictate the need to study the mechanisms of combustion products toxicity, including the assessment of their neurotoxic effect. The study aims to assess the effect of acute peat smoke intoxication on the indices of the functional state of the central nervous system of white rats. Materials and methods. The studies were performed on 20 white outbred male rats exposed to peat smoke for 4 hours. A day after the end of the exposure, the animals were examined using the open field and Morris water maze tests. EEG indices were also assessed. Results. Exposure to peat smoke for 4 hours was accompanied by a pronounced inhibition of the motor and exploratory activity of white rats, as evidenced by a decrease in the distance traveled and a decrease in the area of the studied arena compared to the control group. The results of electroencephalography revealed a statistically significant decrease in the average EEG amplitude in the left and right hemispheres by 23% and 20%, and a decrease in the average signal power in the θ-frequency range by 10–11%, α-rhythm and β1-rhythm — by 22-27%. Conclusion. Our results indicate that a single 4-hour inhalation exposure to smoke from thermal destruction of peat containing the main components: CO — 24 mg/m3 and PM2.5 — 0.32 mg/m3 causes changes in both the rats' behavior and EEG parameters. In the formation of neurotoxicity in rats when inhaling smoke from thermal destruction of peat, the leading role belongs to solid particles with a diameter of less than 2.5 μm (PM2.5). Even though the CO content in the air of the inoculation chambers was close to the maximum permissible level in the air of the working area, in combination with PM2.5 and other gases of the smoke fraction, the occurrence of a potentiation of the toxic effect is likely. Limitations. The study is limited to examining behavioral and electroencephalographic parameters in male albino rats exposed to peat smoke for 4 hours. Ethics. The study was carried out in compliance with the principles set out in the European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes ETS N123, GOST 33215-2014 and approved by the Ethics Committee of the East Siberian Institute of Medical and Ecological Research (Protocol No. 7 dated December 15, 2023).

Introduction. Long-term smoke from landscape fires causes various health problems, primarily affecting the respiratory, cardiovascular, and nervous systems. To substantiate safe levels of exposure to smoke from landscape fires, it is necessary to create an adequate biological model for smoke that is close to natural conditions. The aim of the study is to develop and test methodological approaches to creating a biological model for smoke during landscape fires to substantiate safe levels of exposure. Materials and methods. Using the developed biological model, we studied the effects of smoke from landscape fires on white rats. We assessed the functional state of the central nervous system based on rat behaviour and EEG examination results, conducted a morphological study of the cerebral cortex and testes of white rats, and examined the offspring immediately after birth and at puberty. Results. We studied the biological response of white rats exposed to inhalation smoke from landscape fires for different durations. The main criterion indicators of health disorders in the central nervous and reproductive systems of animals were identified. Limitations. The study is limited by the lack of data on safe levels of exposure to smoke from landscape fires on the central nervous system and reproductive toxicity. Conclusion. Testing of the developed method allowed identifying the exposure load of carbon monoxide and ultrafine particles PM2.5, at which changes in the nervous and reproductive systems are minimal. A method for calculating safe levels of exposure for the central nervous and reproductive systems, as well as for the effect on offspring, is proposed. An algorithm for conducting research in studying the effect of smoke from landscape fires on the body has been developed.

Introduction. A promising area of nanotoxicology is the study of the effects of gadolinium nanoparticles on a living organism, which will allow achieving high image contrast when performing MRI with a significantly smaller amount of the injected substance. This is possible using high-molecular compounds, for example, arabinogalactan of Siberian larch, which has a stabilizing effect for nanoparticles. Materials and methods. Experimental studies were performed on ninety six mongrel white male rats weighing 180–240 g, divided into 3 groups (one control and two experimental). A water-based solution was used as the exposed substance, which included gadolinium nanoparticles, as well as a nanostabilizing matrix – the natural polysaccharide arabinogalactan. The solution was administered orally for 10 days in two doses – 500 and 5000 mcg of gadolinium per 1 kg of animal body weight. After the introduction, some of the animals were withdrawn from the experiment and made up the early examination period, the remaining part of the animals were left to survive for 6 months and made up the long-term examination period, and subsequently were also withdrawn from the experiment. The work used a set of studies aimed at determining neurotoxicity – the “Open Field” test, EEG examination, morphological and morphometric methods. Results. The structural and functional features of the effect of gadolinium nanocomposite on the central nervous system were expressed in an increase in the number of degeneratively altered neurons when administered a solution at a dose of 500 mcg of gadolinium per 1 kg of animal body weight in the early period of examination, while indices reflecting approximate research activity, behaviour and EEG indices, compared with the control, did not changed. Limitations. When studying the effects of gadolinium nanoparticles encapsulated in the polysaccharide arabinogalactan on 96 outbred male rats, which is sufficient to use a set of methods to determine the functional state of the central nervous system and structural changes in nervous tissue. Conclusion. Thus, the subacute effect of gadolinium nanoparticles encapsulated in the arabinogalactan matrix causes structural changes in the nervous tissue, while functional changes in the central nervous system were not observed.

first_page Download PDF settings Order Article Reprints Font Type: Arial Georgia Verdana Font Size: Aa Aa Aa Line Spacing:    Column Width:    Background: Open AccessAbstract Effects of Wildfire Smoke on the Reproductive Potential of Male Rats † by Vera A. VokinaVera A. Vokina SciProfiles Scilit Preprints.org Google Scholar *, Larisa M. SosedovaLarisa M. Sosedova SciProfiles Scilit Preprints.org Google Scholar , Elizaveta S. AndreevaElizaveta S. Andreeva SciProfiles Scilit Preprints.org Google Scholar , Mikhail A. NovikovMikhail A. Novikov SciProfiles Scilit Preprints.org Google Scholar and Evgeniy A. TitovEvgeniy A. Titov SciProfiles Scilit Preprints.org Google Scholar FSBSI East-Siberian Institute of Medical and Ecological Research, 665827 Angarsk, Russia * Author to whom correspondence should be addressed. † Presented at the 1st International Electronic Conference on Toxics, 20–22 March 2024; Available online: https://sciforum.net/event/IECTO2024. Proceedings 2024, 102(1), 14; https://doi.org/10.3390/proceedings2024102014 Published: 3 April 2024 Download keyboard_arrow_down Download PDF Download PDF with Cover Download XML Download Epub Versions Notes Keywords: wildfire smoke; rats; offspring; reprotoxicity Introduction. The negative impact of wildfire smoke on human health is a unique interdisciplinary problem for the modern scientific community. Despite the fact that wildfires have recently become global, many aspects of the toxic effects of smoke and its components on human health remain unknown. Epidemiological data today convincingly prove the negative impact of smoke from wildfires on human health. At the same time, the multi-component composition of smoke and the presence of potential repro- and genotoxicants determines the need for a comprehensive study of the toxic effects of smoke on the reproductive system, including remote effects manifested in the offspring.Methods. Adult Wistar male rats were exposed to wildfire smoke inhalation for 1 day, 1 week and 4 weeks (4 h/day, 5 days/week). A histological examination of the gonads and the survival and postnatal development of offspring was carried out.Results. Smoke exposure for 1 day and 7 days did not reveal a pronounced effect on spermatogenesis parameters. However, increasing the duration of exposure to 4 weeks led to a decrease in the spermatogenesis index and Leydig cells. With exposure to smoke for 4 weeks, the incidence of stillbirth was more pronounced and amounted to 29.4%, while the rate of death of rat pups in the first week of life was 3.6%.Conclusion. The results obtained can be considered as a fundamental basis for the development of preventive health-saving measures for both the general population and forest firefighters. In addition, the identified dependencies will make it possible to contribute to the assessment of environmental damage from natural fires when assessing the potential ability of small mammals to reproduce. Author ContributionsConceptualization, V.A.V. and L.M.S.; methodology, L.M.S.; software, V.A.V., L.M.S. and M.A.N.; validation, V.A.V. and M.A.N.; formal analysis, M.A.N.; investigation, V.A.V., E.A.T., E.S.A. and M.A.N.; resources, L.M.S.; data curation, V.A.V.; writing—original draft preparation, L.M.S. and V.A.V.; writing—review and editing V.A.V.; visualization, V.A.V.; supervision L.M.S.; project administration, V.A.V.; funding acquisition, L.M.S. All authors have read and agreed to the published version of the manuscript.FundingThe work was carried out according to the research plan within the framework of the state task and was supported by the Ministry of Science and Higher Education of the Russian Federation, the grant No. 075-15-2020-787 for implementation of Major scientific projects on priority areas of scientific and technological development (the project «Fundamentals, methods and technologies for digital monitoring and forecasting of the environmental situation on the Baikal natural territory»).Institutional Review Board StatementThe study was conducted according to the guidelines of the Declaration of Helsinki and was approved by Ethics Committee of FSBSI East-Siberian Institute of Medical and Ecological Research (protocol code E32/19; date of approval: 10 September 2019).Informed Consent StatementNot applicable.Data Availability StatementThe data presented in this study are available on request from the corresponding author.Conflicts of InterestThe authors declare no conflict of interest.Disclaimer/Publisher's Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Share and Cite MDPI and ACS Style Vokina, V.A.; Sosedova, L.M.; Andreeva, E.S.; Novikov, M.A.; Titov, E.A. Effects of Wildfire Smoke on the Reproductive Potential of Male Rats. Proceedings 2024, 102, 14. https://doi.org/10.3390/proceedings2024102014 AMA Style Vokina VA, Sosedova LM, Andreeva ES, Novikov MA, Titov EA. Effects of Wildfire Smoke on the Reproductive Potential of Male Rats. Proceedings. 2024; 102(1):14. https://doi.org/10.3390/proceedings2024102014 Chicago/Turabian Style Vokina, Vera A., Larisa M. Sosedova, Elizaveta S. Andreeva, Mikhail A. Novikov, and Evgeniy A. Titov. 2024. "Effects of Wildfire Smoke on the Reproductive Potential of Male Rats" Proceedings 102, no. 1: 14. https://doi.org/10.3390/proceedings2024102014 Article Metrics No No Article Access Statistics Multiple requests from the same IP address are counted as one view.

Exposure of Parental Rats to Mercury Chloride during Progenesis Affects the CNS Parameters of the Adult Offspring

Introduction. An increase in the number of wildfires, along with the lack of a chemical control system for the quality of the atmosphere during smoke, leads to a risk of developing health disorders for rescuers and firefighters exposed to high concentrations of toxic smoke components. The study aims to identify causal relationships based on experimental modeling between exposure to natural fire smoke and the functional state of the nervous and reproductive systems. Materials and methods. The authors conducted studies on white rats of both sexes. The animals were placed in inhalation chambers and exposed to forest fire smoke of varying concentrations and duration of exposure. The scientists examined the functional state of the nervous system (open field method, Morris test, electroencephalography, histology of nervous tissue), the reproductive system (number of Leydig cells, average number of spermatogonia, spermatogenesis index), the presence of genotoxicity (DNA comet method), DNA methylation and the effect on offspring (postnatal development, species-specific behavior). We calculated the total exposure limit in each group of animals in accordance with the indicators of CO and PM2.5 content in the chambers. Results. The researchers found that with a total exposure load of 0.03–0.22 mg, there were initial changes in the morphofunctional state of the central nervous system. With an increase in the load to 4 mg, violations of the indicators of behavior and electrical activity of the brain were accompanied by significant changes in the structure of the nervous tissue of the rat brain. The reproductive function of rats under the influence of smoke changed, starting with a total exposure dose of 10.8 mg. We observed a decrease in spermatogenesis and a change in the cyclic function of the ovaries. A violation of the postnatal development of offspring has already been detected with a total dose of 0.22 to 4 mg. Prolonged exposure to tobacco smoke for one month was accompanied by a pronounced violation of the spermatogenetic function of the testicles and an increase in neonatal mortality in offspring, as well as a violation of the structure of behavior and spatial memory in adulthood. The genotoxic effect of smoke was not detected, and a change in DNA methylation in blood cells was detected at the maximum total dose of smoke components. Limitation. The study is limited to studying the effect of wildfire smoke on the nervous and reproductive systems of mongrel white male rats. Conclusion. The results obtained are a fundamental foundation for solving such tasks as the development of risk-oriented preventive health-saving measures for workers in extreme situations in conditions of smoke during wildfires and making effective management decisions. Ethics. The study was approved by the local Ethics Committee of the East-Siberian Institute of Medical and Ecological Research (Protocol LK of East-Siberian Institute of Medical and Ecological Research No. 32/19 dated 09/10/2019), conducted in accordance with the European Convention for the Protection of Vertebrates Used for Experiments or Other Scientific Purposes (ETS No. 123), Directive of the European Parliament and the Council of the European Union 2010/63/EC dated 09/22/2010 on the protection of animals used for scientific purposes.

Climate change is intensifying the global activity of wildfires, in connection with which the liquidators of the Ministry of Emergency Situations are increasingly exposed to dangerous air pollution during large-scale smoke. Objective: to conduct a comparative characterization of the burning products effect released during wildfires of different duration on the functional state of the reproductive system of white rats. Materials and methods. Experimental studies were carried out on 230 mongrel white sexually mature rats. The duration of exposure was carried out in 3 different exposure modes, for 1 day, 7 days for 4 hours a day and 4 weeks for 5 days a week for 4 hours a day. After the end of exposure, the functional activity of the sexual gonads of animals, mating for offspring and evaluation of their postnatal development were evaluated. 19 Results. It was found that prolonged exposure to smoke for 4 weeks, 5 days a week, has the most pronounced effect on the spermatogenesis indicators of mature male rats. Exposure to smoke for 1 day and 7 days did not have a significant effect on the spermatogenesis of white rats, however, an increase in postnatal mortality was found in the offspring of the first generation, which was observed in all exposure modes. Conclusions. Exposure to the smoke of a natural fire affects the male reproductive potential of animals, resulting in a decrease in the survival rate of their newborn offspring.

Introduction. The impact of combustion products of organic substances on the body is known to be accompanied by the accumulation of DNA damage, which can lead to mutations and pathological changes in the cell and the whole organism. The prevalence and scale of this phenomenon poses an important task for studying the consequences that occur in smoke-exposed organisms and their offspring. Materials and methods. The conditions of real peat smoke were reproduced for 40 minutes with a CO concentration of 99±2.5 mg/m3 with using of experimental bio modelling. The genotoxicity of peat fire smoke after exposure to male white rats was assessed by the occurrence of DNA damage in blood cells using the DNA comet method in the alkaline version. In the first part of the experiment, males were directly exposed to the smoke of a peat fire; in the second part – their sexually mature offspring of both sexes were examined for the occurrence of DNA damage in blood cells. Results. The males of the parental generation and offspring were found to be resistant to the effects of smoke components, which was confirmed by the absence of statistical significance in terms of «% DNA in the comet tail» compared with the control. At the same time, females of the received generation showed a statistically significant increase in blood cell DNA damage compared to the control group. Limitations. The study was limited to the study of DNA fragmentation after a single 40-minute exposure to peat smoke in male white rats and their intact offspring. Conclusion. The data obtained in this investigation indicate that damage to the DNA structure in the offspring of male rats exposed to peat smoke containing CO at a concentration of 99±2.5 mg/m3 can be considered as a bioindicator of genotoxic effects induced in the next generation.

We studied the cytotoxic effect of gadolinium nanocomposite on cultured mouse fibroblasts 3T3-SV40 and histological changes in the liver tissue of albino rats after its administration. For in vitro experiment, gadolinium nanocomposite on the natural matrix of arabinogalactan (nGd-AG) was dissolved in DMEM nutrient medium to concentrations of 0.005, 0.02, 0.5, 2, and 5 mM. In in vivo experiment, a nGd-AG solution was orally administered to rats through a tube in a dose of 500 μg Gd/kg in 1 ml of 0.9% NaCl for 10 days. The pattern and degree of influence of the gadolinium nanocomposite on the studied cell culture depended on the concentration and duration of exposure. IC50 of nGd-AG determined after cell incubation for 24, 48, and 72 h were 616 μg/kg (3.9 mM), 302 μg/kg (1.9 mM), and 222 μg/kg (1.4 mM), respectively. Histological changes in the liver of white rats induced by exposure to nanocomposite attested to the development of a compensatory reaction of the organ.

Introduction. The regular occurrence of large-scale peat fires is an urgent medical and environmental problem of the modern scientific community. The peat smoke is a complex mixture of pollutants that have a serious impact on air quality and public health. Materials and methods. Adult male rats were exposed to peat smoke for 24 hours, the concentrations of PM2.5 and CO were 0.92±0.08 mg/m3 and 40.8±1.9 mg/m3, respectively. After exposure an open field examination, EEG examination and histological analysis of the testes and brain were performed, after which they were mated with intact females. Postnatal death of offspring in the first week of life, body weight, behaviour and electroencephalography indicators during puberty were evaluated. Results. There was showed an increase in motor activity, anxiety, and violation of EEG indicators in rat males exposed to peat smoke. Both an increase in shadow cells and degeneratively altered neurons in the nervous tissue were found. No changes were detected in the testes. Exposure to peat smoke during conception increased stillbirth and mortality of offspring during the first week of life, but did not affect weight gain. Violation of behaviour structure was recorded only in females offspring. An increase in slow-wave activity of the brain in males offspring was revealed. Limitations. The study was limited to studying the effects of a single 24-hour exposure to peat smoke on outbred white rats. Conclusion. A single peat smoke exposure for 24 hours at a concentration of PM2.5=0.92±0.08 mg/m3 and CO=40.8±1.9 mg/m3 leads to significant morphological and functional changes in the CNS. In the absence of a gonadotoxic effect, peat smoke exposure on males before mating causes specific changes in the behavior and bioelectrical activity of the brain of their offspring.

Introduction. The relevance of this work is due to the growing environmental problem associated with large-scale forest fires and insufficient knowledge of the survival, adaptation and reproduction of animals after prolonged exposure to harmful smoke components. The aim of the review is to collect and analyze information on environmental pollution due to smoke from forest fires and their impact on animals in the smoke zone. Material and methods. The material for the analysis was the literature sources published for the period up to 2022, in publications indexed in the Scopus, Web of Science, Publons, Springer, PubMed databases, including domestic and foreign research scientists on this topic. Results. When forest fires occur, a mixture of gaseous compounds is released into the environment, containing ultrafine solid particles, carbon monoxide, ozone, polycyclic aromatic hydrocarbons, nitrogen and sulfur dioxide, aldehydes, chlorinated dioxins, free radicals and many other compounds. At the same time, significant damage is caused to a wide biodiversity of the animal world, which is an extremely important indicator link in almost any biocenosis. Conclusions. The increase in large-scale smoke is increasingly leading to the risk of extinction of wildlife exposed to high concentrations of toxic components of smoke. It is necessary to constantly maintain and restore the biotic potential of populations of endangered species in forest ecosystems, as well as a deeper study of the mechanisms of the occurrence of consequences that are dangerous for the animal organism when exposed to forest fire smoke.

We studied the reproductive function of albino male rats after long-term exposure to wildfire smoke and the species-specific behavior of their sexually mature offspring. After the end of exposure, the mean number of spermatogonia and the relative number of Leydig cells in rat testes decreased and the index of spermatogenesis decreased. The offspring of exposed males mated with intact females demonstrated impaired cognitive abilities and disturbances of species-specific behavior. The severity of these changes depended on time interval between the end of the inhalation exposure and mating.

This study aimed to follow the neurotoxic effect of peat smoke on adult outbred rats and its influence on central nervous system (CNS) parameters in first-generation offspring. Under experimental conditions, exposure to peat smoke was carried out on adult male Wistar rats for 24 h. After the end of the exposure, an open field test (OFT), electroencephalography (EEG), and histological analysis of the testes and brains of smoke-exposed males were performed, after which they were mated with intact females to obtain F1 offspring. Stillbirth, neonatal mortality, and body weight at 4, 7, 14, and 21 postnatal days, as well as behavior in the OFT and EEG parameters during puberty (3 months), were assessed. The results of the examination of F0 males showed a significant increase in motor activity and anxiety in the open field test and a violation of EEG parameters. Histopathologically, peat smoke caused a sharp increase in shadow cells (homogeneous cells with pale-stained cytoplasm, in which the cell and nuclear membranes are not visualized) and degeneratively altered neurons in the brain; we found no changes in the testicles. Peat smoke exposure during preconception did not affect neonatal mortality and weight gain in F1 offspring. Adult females born to peat-smoke-exposed males showed an increase in locomotor activity, and the behavior of adult F1 males did not differ from the control. In F1 males, a statistically significant increase in slow-wave activity indices in the delta band was observed.

Introduction. In landscape fires, the question of the nature and character of the formed organic substances remains unexplored. The method of gas chromatography with mass spectrometric detection (GC-MS) has long been used in environmental analysis to identify organic compounds in complex multicomponent mixtures. Depending on the volatility and polarity of the components of organic compounds, air sampling is carried out on a solid sorbent, liquid absorber, fiber filter. The purpose of this study is to develop a comprehensive procedure for the identification of organic compounds by gas chromatography-mass spectrometry with sampling into different absorption media. Materials and methods. The studies were carried out in laboratory conditions specially created in the smoldering plant, seed chamber, chemical-analytical equipment. Biomass consisting of forest litter was used as a fuel substrate: moss, lichen, tree litter, branches, pieces of bark. An Agilent 5975 gas chromatography-mass spectrometer was used for GC-MS identification. An aspirator, a gas pipette, a Richter absorber with distilled water, and an AFA-HP-20 fiber filter were used to select the air medium. Sample preparation of concentrated air was carried out using microfibre “85 microns Carboxen/PDMS”, thermostat, vials for vapor phase analysis, ultrasonic bath, derivatizing reagent - o-pentafluorobenzylhydroxylamine, hexane. Results. A proposed complex procedure includes sampling into different absorption media, various sample preparation options. Extraction of organic compounds from absorption media was carried out by methods of solid-phase microextraction, derivatization, and liquid extraction. Volatile organic compounds were extracted from a gas bulb by the method of solid-phase microextraction on microfibre“85 microns Carboxen/PDMS”. Aldehydes and ketones were found in distilled water due to the derivatization of o-pentafluorobenzylhydroxylamine. Semi-volatile compounds were detected on the AFA-HP-20 filter due to liquid extraction in ultrasound. Limitations. The limitations of the study are related to the need to select the products of decay of a sample of forest litter under model conditions. Conclusion. The identification results showed that the following classes of substances released into the air during the burning of forest litter are present in the maximum amount: aldehydes, phenols, terpenes. The coefficient of coincidence of mass spectra also confirmed by the coincidence of experimental and library retention indices also confirmed by the coincidence of experimental and library retention indices is more than 90%.

The assessment of the indicators of the reproductive potential of male white rats exposed to smoke for 1 month was carried out. Examination of exposed animals included determination of the spermatogenesis index and the level of DNA fragmentation and methylation in the testes and blood. A statistically signifi-cant increase in the level of genome-wide methylation in the blood of rats exposed to smoke was revealed. A morphometric study of the testis tissue revealed a violation of spermatogenesis indices in exposed rats.

Introduction. The adverse negative effect of forest fire smoke on human health represents a unique interdisciplinary challenge to the scientific community. The influence of forest fire smoke on locomotor activity, cognitive indices, and brain bioelectrical activity parameters in exposed rats is presented. Materials and methods. Experimental studies were carried out on outbred white male rats. The animals of the experimental group were exposed to smoke inhalation forest fire for one day. Immediately after the end of the exposure, the animals were examined, including testing in an open field and Morris water maze, as well as an electroencephalographic examination. Results. At twenty-four-hour exposure to wildfire smoke in the model, conditions showed increasing motor and research activity of male rats against the backdrop of growing anxiety. Disorders of indicators of spatial memory and navigation learning were not revealed. On the encephalogram of the exposed animals, in comparison with the control group, the δ-rhythm range predominated, more pronounced in the leads of the right hemisphere. A decrease in the power spectrum and the average amplitude β1-rhythm, as well as a tendency to decrease the average amplitude of θ-rhythm, were revealed. The indices of the primary EEG rhythms did not have statistically significant differences when compared with the control group. Conclusion. The results showed that forest fire smoke leads to changes in the bioelectric activity of brain structures and dysregulation of individual behaviour in animals, all of which may indicate the formation of increased levels of stressing beyond physiological adaptation.

The use of a developed experimental model of a natural fire made it possible to assess the consequences of 24 h exposure to peat combustion products in albino rats. Peat smoke exposure leads to behavioral disturbances in rats, characterized by an increase in locomotor activity and an increased level of anxiety. Indicators of brain bioelectrical activity of the exposed animals supported the state of anxiety and psychoemotional stress. Epigenetic changes in the blood cells of exposed animals were revealed under 24 h exposure to peat smoke, characterized by a decrease in the level of global DNA methylation.