ULTRASTRUCTURAL CHANGES IN THE MYOCARDIUM IN THE ACTION OF GENERAL HYPOTHERMIA

Belimenko M. S., Kosharniy V. V., Abdul-Ogli L. V., Kushnareva K.A.

MORPHOLOGY

Scentific article

Abstract. General hypothermia is used in operations requiring a temporary arrest of blood circulation (operations on an open – “dry” – heart, aortic aneurysm operations, etc.). With a decrease in body temperature to 25° С, a possible cessation of blood circulation for 10-15 minutes. When cooling below 20°С – for 45 minutes. and even more. Hypothermia reduces the sensitivity of tissues to oxygen deprivation, which allows the brain to tolerate reduced circulation without harm. At the same time, the dynamics of morphological changes in organs under the influence of non-fatal hypothermia remains not described. In this regard, the study of the action of hypothermia is an urgent issue, both for theoretical and practical medicine. Simulation of hypothermia was performed in a refrigerator. Animals were cooled for 3 hours at a temperature of 10°C. After withdrawal from the experiment was performed histological and ultramicroscopic examination. The aim of the study was to study changes in the myocardium under the action of general hypothermia at different levels of structural organization. Our studies of the myocardium of the heart wall of rats using transmission electron microscopy showed that the use of this method allows us to assess the processes of remodeling the heart after hypothermia and confirm the completeness of the structure of the studied objects. The intercellular space between individual cardiomyocytes is increased. The oval nuclei in most cardiomyocytes are located mainly in the center of the cells, in some they are displaced to the periphery. The intercellular space between adjacent cardiomyocytes is larger than in the outer layer. On histological sections, hyperemic vessels, endothelium of small vessels and swollen capillaries were found. At the ultrastructural level, perevascular edema, edema of the mitochondrial cristae apparatus, erethrocytic sludge syndrome was revealed. In cardiomyocytes, swelling of the sarcoplasm is noted, especially in the zone of contact with the capillaries. There were few intermitochondrial contacts. Intermyofibrillar mitochondria were large, with moderately developed cristae and a transparent matrix. Among such organelles, organelles with elements of crystallization and zones of sharp enlightenment predominated matrix. The revealed changes indicate the microcirculatory bed and the cell energy supply apparatus in aggregate indicate the activation of adaptive processes arising in cardiomyocytes under the influence of general hypothermia.

myocardium, hypothermia, ultrastructure, transmission electron microscopy

1. Babiychuk VG. Ul’trastrukturnyye perestroyki miokarda molodykh i starykh krys posle ekstremal’noy krioterapii. Problemy kriobiologii. 2006;16(3):292-302. [in Ukrainian].
2. Lutsenko MT, Lutsenko MM, Shmatok MI. Povrezhdayushcheye deystviye nizkikh temperatur na miofibrilly kardiomiotsitov. Byulleten’ fiziologii i patologii dykhaniya. 2013;48:56-2. [in Russian].
3. Trofimova AV, Chizh NA, Repin NV, Belochkina IV, Sandomirskiy BP. Vliyaniye terapevticheskoy gipotermii i mezenkhimal’nykh stromal’nykh kletok na ul’trastrukturu kardiomiotsitov krys c eksperimental’nym infarktom miokarda Problemy kriobiologii i kriomeditsiny. 2017;27(2):166. DOI: https://doi.org/ 10.15407/cryo27.02.166. [in Ukrainian].
4. Pisarev VB, Novochadov VV, Zaripova IV. Ul’trastruktura kardiomiotsitov pri patologii serdtsa, vyzvannoy khronicheskoy endogennoy intoksikatsiyey i tsitostatikami. Vestnik Volgogradskogo gosudarstvennogo meditsinskogo universiteta. 2007;4(24):36-39. [in Russian].
5. Kosharniy VV, Rutgayzer VG, Abdul-Ogli LV, Kushnar’ova KA, Bondarenko NS, Tverdokhlíb ÍV. Ul’trastruktura mítokhondríal’nogo aparatu kardíomíotsitív lívogo shlunochka sertsya shchurív píslya díí̈ ríznikh yekspozitsíy yelektromagnítnogo opromínennya za umov gípotireozu. Morfologíya. 2019;13(4):16 – 23. [in Ukrainian]
6. Lutsenko MT, Lutsenko MM. Morfofunktsional’naya kharakteristika miokarda krolikov podvergshikhsya obshchemu okhlazhdeniyu. Zdorov’ye. Meditsinskaya ekologiya. Nauka. 2009;4.5(39.40):116-118. [in Russian].
7. Bilash SM, Pronina OM, Koptev MM. Comprehensive morphological studies as an intergal part of modern medical science. Literature review. Visnyk problem biolohiyi i medytsyny. 2019;2.2(151):20-3. DOI: 10.29254/2077-4214-2019-2-2-151-20-23.

«Bulletin of problems biology and medicine» Issue 1 (159), 2021 year, 197-201 pages, index UDK 616.12:616-001.8:616.127-092.4

10.29254/2077-4214-2021-1-159-197-201