Postnatal development of male rat offspring exposed to peat fire smoke: an experimental model of reproductive toxicity

Introduction. The occupational safety system of firefighters involved in extinguishing forest fires focuses on injuries, burns, and acute intoxication, while the effect of smoke from forest fires on offspring and their development remains poorly understood. The development of methods for identifying biomarkers capable of predicting an unfavorable outcome for offspring is an important task of preventive medicine and occupational pathology.

The study aims to evaluate the effect of peat fire smoke on the postnatal development of the offspring of exposed males.

Materials and methods. The authors carried out the inhalation effect of peat smoke on male rats in inhalation chambers for 4 hours for five days. The CO content was 21(13;28) mg/m³, PM_2.5 — 0.09(0.04;0.19) mg/m³. After mating with intact females, offspring were obtained in which survival, physical development, and sensorimotor parameters in the early postnatal period were studied.

Results. The inhalation effect of peat smoke on male rats had no negative effect on their ability to reproduce. The mortality rate of offspring by the 21^st day of life in the experimental group exceeded the level in the control group. In rat pups whose fathers were exposed to peat smoke, there was a delay in the timing of eruption of the lower incisors, eye opening, later maturation of sensory-motor reflexes and a decrease in locomotor activity. In general, the work substantiates the patterns of formation of long-term consequences of exposure to smoke from landscape fires, manifested by a decrease in survival, impaired development of sensory motor skills and the neurobiology of offspring behavior.

Limitations. The study was performed on a rodent model (Wistar rats), which may limit the extrapolation of the results to other species and to humans. The study is limited to the study of physical development and sensorimotor reflexes in rats in the early postnatal period, born to mature adult males exposed to peat smoke, and does not take into account possible long-term effects. In this work, the coefficients of physical and harmonious development of offspring were not used and will be included in subsequent studies focused on a more detailed quantitative assessment of reproductive toxicity. It should also be considered that direct correlations with the human population require validation in clinical and epidemiological studies.

Conclusions. Based on the revealed patterns, the researchers developed criteria for detecting the reproductive toxicity of smoke from landscape fires: increased mortality; impaired physical development (weight gain, late eruption of incisors); delayed maturation of sensorimotor reflexes; decreased muscle strength; decreased motor activity and increased stress levels. Broadcasting the results of the experimental study will make it possible to assess the risk of developmental disorders in young children among fire extinguishers. The consequences of postnatal disorders can be permanently fixed in ontogenesis and persist until puberty, burdening the process of learning and social integration and contributing to the development of increased anxiety and depression.

Ethics. The study was conducted in accordance with the European Convention for the Protection of Vertebrate Animals Used for Experiments or Other Scientific Purposes (ETS No. 123), Directive 2010/63/EC of the European Parliament and of the Council of the European Union of 22.09.2010 on the protection of animals used for scientific purposes. The study was approved by the local Ethics Committee of the East-Siberian Institute of Medical and Ecological Research (Protocol No. 7 dated December 15, 2023).

Contributions:
Sosedova L.M. — research concept and design, literature review on the topic of the article, data analysis and interpretation, text writing, editing;
Vokina V.E. — research concept and design, experiment, statistical data processing, data analysis and interpretation, literature review on the topic of the article;
Pankova A.A. — conducting an experiment, collecting and primary processing of material, statistical data processing.

Funding. The work was carried out according to the research plan within the Framework of the state assignment.

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

Received: 08.07.2026 / Accepted: 23.07.2026 / Published: 11.08.2026

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