Analysis of changes in the rat cardiovascular system under the action of lead intoxication and muscular exercise

Introduction. One of the risk factors for cardiovascular diseases is the toxic metal pollution of the industrial area and the environment. Lead is the most critical of toxic metals. In industrial conditions, the body’s exposure to harmful substances is often combined with muscular work of varying severity. It has not been studied enough how these combinations influence the development of pathological processes associated with harmful exposure.

Materials and methods. The subchronic experiment was carried out on white outbred male rats for six weeks. Intoxication was simulated by repeated intraperitoneal injections of lead acetate three times a week. Running was chosen to model the muscle exercise at a 25 m/min speed for 10 minutes 5 days a week. We performed biochemical and electrocardiographic studies. Blood pressure parameters were recorded. Muscle contractility was studied on isolated multicellular preparations of the right ventricular myocardium in isometric and physiological contraction modes. The ratio of myosin heavy chains was determined by the polyacrylamide gel electrophoresis. The sliding velocity of reconstituted thin filaments on myosin using an in vitro motility assay. 

Results. Physical exercise under lead intoxication normalized the level of calcium and the angiotensin-converting enzyme activity in the blood serum, the voltage of the isoelectric line and the amplitude of the T wave on the electrocardiogram. The combined action of lead and physical exercise showed an increase in the creatinine kinase-MB level. We found that the effect of exercise under lead intoxication on myocardial contractility was ambiguous. The maximum isotonic shortening velocity in trabeculae was normalized, but the maximum rate of strength development in the isometric mode in the papillary muscles decreased to a greater extent than under lead intoxication. The maximum sliding velocity of reconstituted thin filaments and myosin and the heavy chain ratio was partly normalized. 

Conclusion. In general, muscle exercise attenuated the lead cardiotoxic effects.

Contribution:

Klinova S.V. — collection of literature data, collection and processing of material, writing a text;

Minigalieva I.A., Protsenko Yu.L., Nikitina L.V. — the concept and design of the study, editing;

Sutunkova M.P., Privalova L.I. — the concept and design of the study;

Ryabova Iu.V. — collection of literature data, collection and processing of material;

Gerzen O.P. — collection of literature data, writing a text;

Nabiev S.R., Balakin A.A., Lookin O.N., Lisin R.V., Kuznetsov D.A., Chernyshov I.N. — collection and processing of material;

Panov V.G. — statistical and mathematical processing;

Katsnelson L.B. — the concept and design of the study, writing a text, editing.

All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version

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

Acknowledgement. The study had no sponsorship.

Conclusion of the Local Ethics Committee of the Federal Service for Supervision of Consumer Rights Protection and Human Well-Being: Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers,of the Federal Service for Supervision in Protection of the Rights of Consumer and Man Wellbeing: keeping, feeding, caring for animals and removing them from the experiment was carried out in accordance with the requirements of the Declaration of Helsinki and “International guiding principles for biomedical research involving animals” developed by the Council for International Organizations of Medical Sciences and the International Council for Laboratory Animal Science (2012). The studies were approved by the Local Ethics Committee of the Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers,of the Federal Service for Supervision in Protection of the Rights of Consumer and Man Wellbeing (protocol No. 8 of 08.11.2018).

Received: October 19, 2021 / Accepted: November, 2021 / Published: December 30, 2021