Assessing neurotoxity of peat thermal degradation products in experimental modeling

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).