ISSN 2415-3060 (print), ISSN 2522-4972 (online)
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УЖМБС 2021, 6(2): 31–36
Experimental Medicine and Morphology

Morphometric Indicators of Rat Myocardium under the Action of General Hypothermia

Belimenko M. S., Kosharniy V. V., Abdul-Ogly L. V., Kozlovskaya G. O.

Hypothermia is a situation in which the internal body temperature drops below 35 degrees Celsius. The article presents the relevance, theoretical aspects and features of the action of general hypothermia on the heart in general and cardiomyocytes in particular. The purpose of the study was to study the changes in the myocardium under the action of general hypothermia at different levels of structural organization. The object of the study were the hearts of laboratory adult rats. The study involved 20 animals. The longitudinal section shows that the right ventricle is much thinner than the left and its cavity is presented in the form of a crescent. The interventricular septum is thicker than the wall of the right ventricle and goes into its cavity. Results. To establish the shape of the heart and track the dynamic changes at the organ level, we calculated an index showing the ratio of the width of the heart to its length. In 80% of cases, the heart shape of intact rats was conical, the index averaged 55%, only 20% elliptical, the index was more than 65%. We did not observe other forms of heart in the group of intact rats. In the experimental groups, a spherical heart shape appeared. The thickness of the anterior wall of the left ventricle for 10 days from the beginning of the experiment was 3.15±0.11 mm, the side wall 3.1±0.11 mm, the posterior wall 2.45±0.04 mm, interventricular septum 2.95±0.09 mm. In the right ventricle, the thickness of the anterior wall is 1.04±0.03 mm, the posterior wall is 1.36±0.04 mm. On the 30th day from the beginning of the experiment, the thickness of the anterior wall of the left ventricle was 3.21±0.11 mm, the side wall 2.65±0.06 mm, the posterior wall 3.27±0.09 mm, the interventricular septum 3.14±0.13 mm. In the right ventricle, the thickness of the anterior wall is 1.09±0.04 mm, the posterior wall is 1.38±0.03 mm. Conclusions. The increase in heart mass, change in its shape due to changes in the middle third of the heart wall of both the left and right ventricles. The highest rates were in the middle third of the heart (zone "B"): In all layers of the myocardium there is an increase in the diameter of cardiomyocytes, a decrease in the distance between individual cardiomyocytes and their groups. The distance between adjacent cardiomyocytes in the left ventricle is: in the outer layer 1/8 of the diameter of the cardiomyocyte, between groups of cardiomyocytes 1/4 of the diameter of the cardiomyocyte

Keywords: myocardium, hypothermia, morphometry

Full text: PDF (Ukr) 369K

  1. Dietrichs ES, Tveita T, Smith G. Hypothermia and cardiac electrophysiology: a systematic review of clinical and experimental data. Cardiovasc Res. 2019 Mar 1; 115(3): 501-509. PMID: 30544147.
  2. Doshi HH, Giudici MC. The EKG in hypothermia and hyperthermia. J Electrocardiol. 2015 Mar-Apr; 48(2): 203-9. PMID: 25537312. .jelectrocard.2014.12.001
  3. Miki T, Liu GS, Cohen MV, Downey JM. Mild hypothermia reduces infarct size in the beating rabbit heart: a practical intervention for acute myocardial infarction? Basic Res Cardiol. 1998 Oct; 93(5): 372-83. PMID: 9833149.
  4. 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 [Ultrastructure of the mitochondrial apparatus of the cardiomyocytes of the left ventricle of the heart of rats after the action of different exposures of electromagnetic radiation during hypothyroidism]. Morfologíya. 2019; 13(4): 16–23. [Ukrainian]
  5. Lutsenko MT, Lutsenko MM. Morfofunktsional'naya kharakteristika miokarda krolikov podvergshikhsya obshchemu okhlazhdeniyu [Morphofunctional characteristics of myocardium rabbits undergoing general cooling]. Zdorov'ye. Meditsinskaya ekologiya. Nauka. 2009; 39-40(4-5): 116-8. [Russian]
  6. Lin YK, Sung FC, Honda Y, Chen YJ, Wang YC. Comparative assessments of mortality from and morbidity of circulatory diseases in association with extreme temperatures. Sci Total Environ. 2020 Jun 25; 723: 138012. PMID: 32217384.
  7. Ghani N, Tariq F, Javed H, Nisar N, Tahir A. Low-temperature health hazards among workers of cold storage facilities in Lahore, Pakistan. Med Pr. 2020 Jan 20; 71(1): 1-7. PMID: 31793557.
  8. Isei MO, Kamunde C. Effects of copper and temperature on heart mitochondrial hydrogen peroxide production. Free Radic Biol Med. 2020 Feb 1; 147: 114-128. PMID: 31825803.
  9. Fu XK, Liu YQ, Gao H, Wang GL, Li HY, Dai DJ. [Effects of hypothermia on the repolarization duration of ventricular myocytes in rats and its mechanism]. Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2020 May; 36(3): 228-231. [Chinese]. PMID: 32981277.
  10. Liu Y, Wang P, Wen C, Zheng H, Tang X, Ling Q, et al. Endovascular hypothermia improves post-resuscitation myocardial dysfunction by increasing mitochondrial biogenesis in a pig model of cardiac arrest. Cryobiology. 2019 Aug; 89:6-13. PMID: 31283936.