Experimental study of the specificity of morphological changes in the cardiac muscle in the dynamics of exposure to harmful industrial factors on the body

Introduction. The systemic impact of occupational factors in the coal and metallurgical industries on the human body leads to the involvement of the heart muscle in the pathological process, with changes in its structure manifesting clinically at the stage of pronounced remodeling or decompensation. This necessitates an experimental study of early disturbances in myocardial structure under isolated exposure to the studied harmful factors.The study aims to experimentally investigate the specificity of morphological changes in the heart muscle in the dynamics of exposure to harmful occupational factors: coal rock dust, fluorine compounds, and general vibration.Materials and methods. The authors have conducted their research on male Wistar rats using three experimental models: pneumoconiosis (coal rock dust, 50 mg/m³, 4 hours per day, 5 days per week); fluoride intoxication (NaF, 10 mg/L, 1.2 mg/kg per day); vibration sickness (general vibration, 16 Hz, 120 dB, 4 hours per day, 5 days per week). The duration of exposure to harmful factors was 9–12 weeks. Histological processing of the heart muscle was carried out using standard methods.Results. Prolonged exposure of the organism to the studied production factors is accompanied by the development of morphological changes in the heart muscle, which have both universal and factor specific features. Regardless of the etiology of the damaging agent, the initial stage is the development of compensatory and adaptive reactions in weeks 1–3 of the experiment. Exposure to coal rock dust leads to an early breakdown of compensation and the formation of fibroplastic and destructive changes from the 6th week of exposure. Fluoride intoxication is characterized by the predominance of degenerative necrobiotic processes, which become evident from the 9th week, with relative preservation of the interstitium. Vibrational exposure causes progressive dystrophy of cardiomyocytes from the 6th week of the experiment, which is not accompanied by tissue fibrosis. The universal target for all studied factors is heart vessels, with the development of endotheliosis, medial hypertrophy, and microcirculation disorders.Limitations. The study is limited by the descriptive format of presenting histological changes.Conclusions. The data obtained substantiate the need to implement screening programs to identify preclinical markers of cardiopathies. This will make it possible to carry out timely, pathogenetically grounded therapeutic and preventive measures before the stage of irreversible remodeling of the heart muscle sets in.Ethics. The care, feeding, and withdrawal of animals from the experiment were carried out in accordance with the requirements of the Order of the Ministry of Health and Social Development of Russia "On Approval of the Rules of Laboratory Practice" (No. 708n dated August 22, 2010), the Decision of the Council of the Eurasian Economic Commission “On Approval of the Rules of Good Laboratory Practice of the Eurasian Economic Union in the Field of Circulation of Medicinal Products” (No. 81 dated November 3, 2016), as well as the Guide for the Care and Use of Laboratory Animals (2011). The studies were approved by the local Ethics Committee of the Federal State Budgetary Scientific Institution "Research Institute for Complex Problems of Hygiene and Occupational Diseases" (Protocol No. 3 dated 26.11.2015; Protocol No. 3 dated 26.11.2018; Protocol No. 4 § 2 dated 18.11.2021).Contributions:Bugaeva M.S. — research concept and design, data collection and processing, text writing;Zhukova A.G. — conducting an experiment, collecting and processing material;Gorokhova L.G. — conducting an experiment, collecting and processing material;Kazitskaya A.S. — conducting an experiment, collecting and processing material;Bondarev O.I. — material processing;Gostyaeva E.P. — conducting an experiment, collecting and processing material;Kizichenko N.V. — conducting an experiment, collecting material.Funding. The study had no funding.Conflict of interest. The authors declare no conflict of interest.Received: 03.07.2026 / Accepted: 15.10.2026 / Published: 03.11.2026