The Dynamic Effect of Hypothermia on Structural Changes in the Left Ventricular Myocardium of Wistar Rats

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DOI: 10.22138/2500-0918-2026-23-3-356-366

V.V. Matvienko, G.S. Soloviev, O.V. Rashevskikh, V.A. Shidin, M.E. Martirosyan, I.V. Nemtsova

Tyumen State Medical University, Tyumen, Russian Federation

Abstract

Introduction. Hypothermia is a complex factor significantly affecting the cardiovascular system. The myocardial response to this factor includes not only functional but also profound structural changes. The aim of this study was to comprehensively investigate structural changes in left ventricular (LV) cardiomyocytes and the intercellular matrix during cold exposure. Materials and Methods. The study was conducted on male Wistar rats weighing 150-180 g. The material (left ventricular myocardium) was collected on days 3, 7, and 15 after the onset of cold exposure. The preparations were prepared using standard methods and analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results. Early in cold exposure (day 3), SEM and TEM reveal signs of an acute stress response, which is predominantly reversible. On day 7 of hypothermia, the damage is more systemic and profound, affecting key cellular systems. On day 15, the process transitions to a phase of chronic left ventricular myocardial remodeling. Conclusion. The combined use of SEM and TEM allowed us to establish the staging and multicomponent nature of ultrastructural remodeling of left ventricular components under hypothermia. First, the signs of acute cellular stress are outlined, with activation of energy metabolism, initial microcirculation disturbances, and reversible organelle changes. The next stage is characterized by profound damage to intracellular systems, the onset of an inflammatory response, and the initiation of fibrosis. The chronic remodeling stage is characterized by the persistence of destructive processes, cellular attempts to adapt calcium homeostasis systems, and the progression of fibrosis.

Keywords: cold exposure, rat left ventricular myocardium, cardiomyocytes, cardiomyocyte nuclei, scanning and transmission electron microscopy

There is no conflict of interest.

Contact information of the author responsible for correspondence

Viktor V. Matvienko
matvienko-51@mail.ru
Received: 08.07.2026

For citation

Matvienko V.V., Soloviev G.S., Rashevskikh O.V., Shidin V.A., Martirosyan M.E., Nemtsova I.V. The dynamic effect of hypothermia on structural changes in the left ventricular myocardium of Wistar rats. Vestn. Ural. Med. Akad. Nauki. = Journal of Ural Medical Academic Science. 2026, Vol. 23, no. 3, pp. 356-366. DOI: 10.22138/2500-0918-2026-23-3-356-366 (In Russ)

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Authors

Viktor V. Matvienko
Cand. Sci. (Biol.), Associate Professor, Department of Histology and Embryology named after P.V. Dunaev
matvienko-51@mail.ru
ORCID ID: 0000-0003-4540-2153

Georgy S. Soloviev
MD, Professor, Department of Histology and Embryology named after P.V. Dunaev
solovyev@tyumsmu.ru
ORCID ID: 0000-0003-4553-0569

Olga V. Rashevskikh
Cand. Sci. (Med.), Senior Lecturer, Department of Nursing
kirnmld@mail.ru
ORCID ID: 0000-0002-1002-3535

Vladimir A. Shidin
MD, Professor, Department of Histology and Embryology named after P.V. Dunaev
vshidin@mail.ru
ORCID ID: 0000-0003-1396-5381

Migran E. Martirosyan
Applicant, Department of Histology and Embryology named after P.V. Dunaev
Migran-m@mail.ru
ORCID ID: 0009-0000-9709-5031

Irina V. Nemtsova
Postgraduate Student, Department of Histology and Embryology named after P.V. Dunaev
74174180@mail.ru
ORCID ID: 0000-0003-4146-2933

Tyumen State Medical University
Tyumen, Russian Federation

 
 
 

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