Assessment of the safety of short-term exposure of peat thermal degradation products in sublethal concentrations on rats

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 PM_2.5 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 PM_2.5=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 PM_2.5 in the smoke of landscape fires on the nervous, reproductive, genome/epigenome system of male rats.

Compliance with ethical standards. The study was carried out in accordance with the rules of bioethics approved by the European Convention for the Protection of Vertebrates Used for Experimental and Other Purposes and approved by the Local Independent Ethical Committee of the Federal State Budgetary Scientific Institution “East Siberian Institute of Medical and Ecological Research” (Protocol No. 32 of 10.01.2023).

Author contribution:
Sosedova L.M. – concept, literature search, writing, article design, responsibility for the integrity of all parts of the article;
Vokina V.A. – concept, literature search, conducting an experiment, writing, statistical processing, editing an article;
Titov E.A., Novikov M.A., Tyutrina V.A. – collection and processing of material, statistical analysis.
All co-authors – approval of the final version of the article.

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

Acknowledgment. Thework was carried out according to the research plan within the framework of the state assignment.

Received: July 19, 2024 / Revised: November 2, 2024/ Accepted: December 18, 2024 / Published: February 25, 2025