Structural and functional disorders of the respiratory system in laboratory animals when intoxicated by pyrolysis products of chlorine-containing polymer materials

Relevance. The widespread use of chlorine-containing polymer materials in the modern world is due to their various advantages over natural analogues. Given the continuing large number of fires, there is still a high risk of exposure to pyrolysis products of chlorine-containing polymer materials, primarily hydrogen chloride and carbon monoxide on the victims. The complexity of determining the toxic effect of pyrolysis products of chlorine-containing polymers makes it necessary to conduct toxicological experimental studies.

Intention. The goal is to evaluate the structural and functional disorders of the respiratory system in laboratory animals when intoxicated by pyrolysis products of chlorine-containing polymer materials.

Methodology. In an experimental study, pyrolysis of chlorine-containing polymer materials was performed. The study was performed on 96 male rats, in which vital function indicators, pulmonary coefficient, parameters of oxygenation and acid-base state of arterial blood were determined, and histological examination of tracheal and lung tissues was performed.

Results and Discussion. It was found that the pyrolysis of chlorinated paraffin (CP-70) with a mass of 7 g and sawdust with a mass of 3 g produces thermal degradation products containing hydrogen chloride at a concentration of 7325 ppm and carbon monoxide at a concentration of 1000 ppm. Exposure to pyrolysis products in laboratory animals resulted in a pronounced irritant effect during intoxication and in the early post-intoxication period. Microscopic examination of lung tissue 48 hours after exposure showed histological signs of interstitial phase of toxic pulmonary edema. We found a decrease in vital functions (heart rate, respiratory rate, rectal temperature) 24, 48 and 72 hours after exposure. Exposure to pyrolysis products led to a violation of gas exchange through the alveolar-capillary membrane, which was confirmed by a decrease in the index of oxygenation and saturation. Violation of the integrity of the alveolar-capillary membrane contributed to the penetration of fluid into the interstitial and alveolar space and the development of toxic pulmonary edema. An increase in the pulmonary coefficient (p < 0.05) was observed, after 24 and 48 hours, respectively.

Conclusion. As a result of the study, toxic pulmonary edema was simulated in laboratory animals by inhalation of pyrolysis products of chlorine-containing polymer materials, and structural and functional disorders of the respiratory system were determined. It was found that intoxication with pyrolysis products of chlorine-containing materials led to the development of inflammatory changes in the trachea and the manifestation of interstitial pulmonary edema. These changes were accompanied by the development of bradycardia, bradypnea, a decrease in body temperature, as well as an increase (p < 0.05) in the pulmonary coefficient, and the development of decompensated respiratory acidosis. The obtained results indicate that the formation of a toxic effect when exposed to pyrolysis products is due to the combined action of hydrogen chloride and carbon monoxide.