Experimental study of the specificity of morphological changes development in internal organs with prolonged exposure to coal-rock dust and sodium fluoride to the body

Introduction. Occupational diseases detected at occupational examinations — pneumoconiosis and fluorosis — are, as a rule, chronic, the initial stages of development are almost asymptomatic. Industrial dust affects only the respiratory organs. Specific sign of fluoride intoxication is a lesion of the musculoskeletal system. The information available in the literature on the systemic manifestations of these diseases is not numerous. In this regard, it is relevant to study the early morphological changes, the timing of their occurrence and the features of development, depending on the specificity of the production factor.

The study aims to experimentally identify the specificity of the development of morphological changes in organs and tissues under prolonged exposure to harmful production factors: coal–rock dust and sodium fluoride.

Materials and methods. The authors conducted studies on adult white male laboratory rats. Scientists studied the features of the development of morphological changes in the bronchopulmonary system, heart, liver and kidneys in the dynamics of the impact of production factors on experimental models of anthracosilicosis and chronic fluoride intoxication. For histological examination, specialists carried out organ sampling in animals after 1, 3, 6, 9, 12 weeks of the experiment.

Results. Chronic exposure to coal-rock dust, as well as sodium fluoride, leads to the development of compensatory and adaptive changes in the internal organs in the early stages of the experiment before the formation of degenerative and fibroplastic disorders of the stromal and parenchymal components in the later stages. Inhalation of coal-rock dust creates in experimental animals by an early breakdown of the adaptive mechanisms of the respiratory system and heart muscle. There is a formation from the 6th week of the experiment of pneumosclerosis with the spread to the air-conducting structures, atrophy of the bronchial mucosa, degenerative changes in cardiomyocytes. Despite the early formation of stroma fibrosis, reparative processes restrain dystrophic cell changes in the liver and kidneys. All this develops by the 9^th week of the experiment.

The accumulation of sodium fluoride leads to the early formation of pronounced protein dystrophy of the liver and kidney parenchyma with the development of necrotic changes by the 6–9 weeks of the experiment. Disorders in the bronchopulmonary system before the 9th week of exposure are of the nature of immune inflammation with the subsequent development of degenerative changes in the air-conducting structures. The heart has moderate dystrophy throughout the experiment. Regardless of the influencing factor, changes in the vessels of the studied organs at the initial stages of the experiment lead to hypertrophy of smooth muscle cells of the media and intima, followed by the development of endotheliosis and hyalinosis.

Limitations. The results of the histological examination are descriptive of pathomorphological changes in the bronchopulmonary system, heart muscle, liver and kidneys. We did not conduct a morphometry of various structures of the studied organs has not been carried out with subsequent statistical processing of the results obtained. In this regard, when studying the specifics of the development of morphological changes depending on the influencing harmful production factor, the compared indicators were the first morphological changes and the timing of their formation.

Conclusions. The obtained results have theoretical and practical significance for the development of recommendations for timely preventive and organ-specific therapeutic measures in the premorbid period of the development of occupational diseases.

Ethics. The researchers conducted maintenance, feeding and removal of animals from the experiment in accordance with the requirements of the Order of the Ministry of Health of the Russian Federation "On approval of the Rules of Good Laboratory Practice" (No. 199n of 01.04.2016), as well as the Guide for the Maintenance and Use of Laboratory Animals (Guide for the Care and Use of Laboratory Animals, 1996). Scientists received permission from the Bioethical Committee of the Research Institute of Complex Problems of Hygiene and Occupational Diseases to conduct the study.

Contribution:
Bugaeva M.S. — the concept and design of the study, data collection and processing, writing the text, editing;
Bondarev O.I. — data collection and processing;
Gorokhova L.G. — the concept and design of the study;
Kizichenko N.V. — data collection and processing;
Zhdanova N.N. — collection of literary data.

Funding. The study had no funding.

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

Received: 26.04.2022 / Accepted: 13.05.2022 / Published: 25.06.2022

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