Introduction. The work covers data on the most common forms of functional disorders of the thyroid gland – hypothyroidism and a laboratory research on myocardium, performed on baby rat’s hearts to study dystrophic changes observed in a state of hypothyroidism. The aim of the research is to reveal and analyze dystrophic changes observed in a state of hypothyroidism, which developed as a result of a long-term persistent deficiency of thyroid hormones or decreasing their biological effect on the cellular level. Material and methods. The object of the study was the hearts of 50 white outbred rats of the following age groups: 3, 7, 14, 21, 30 days. Animals were divided into 3 groups. After every experimental week, the hormone level from the rat caudate vein was determined. The control and experimental groups of animals were kept in the same vivarium conditions. At the end of the experiment, the baby rats of the experimental and control groups were killed under anesthesia, the heart was kept in 10% neutral formalin, followed by piping in alcohols, pouring in paraffin and preparing histological sections. Sections of 8-10 microns thick were prepared from paraffin blocks. Microsections were stained with hematoxylin and eosin, van Gieson. Results and discussion. The study process of growth dynamics of the wall thickness of both the left and right ventricles of baby rats’ heart in hypothyroidism state, depending on different parts of the heart, showed that the wall thickness of all departments was less than the control indices. Comparing the thicknesses of wall of the right and left ventricles of the baby rats of the experimental group with the control group, a significant lag in myocardial indices was revealed. Those changes were most pronounced in 14-day-old baby rats, manifested by perivascular and interstitial lymphohistiocytic infiltrate. Conclusion. The intensity and prevalence of morphological changes are less pronounced, destructive changes in the myocardium are not detected. The use of antioxidants in analysis of experimental hypothyroidism on laboratory animals has a protective effect and prevents the development of severe destructive changes in the myocardium.
1. Abohashem-Aly, A.A., Meng, X., Li, J., Sadaria, M.R., L Ao, Wennergren, J., Fullerton, D.A., Raeburn, C.D., 2011. DITPA. A thyroid hormone analog, reduces infarct size and attenuates the inflammatory response following myocardial ischemia. J. Surg. Res. 171, 379– 385. 2. Bocos-Terraz JP., Izquierdo-Alvarez S., Bancalero-Flores JL. et al. Thyroid hormones according to gestational age in pregnant Spanish women // BMC Res Notes. 2009. Vol. 26 (2). P.237. 3. Castillo Lara M., Vilar Sánchez Á., Cañavate Solano C. et al. Hypothyroidism screening during first trimester of pregnancy // BMC Pregnancy Childbirth. 2017. Vol. 17 (1). P.438. 4. Li C., Shan Z., Mao J. et al. Assessment of thyroid function during first trimester pregnancy: what is the rational upper limit of serum TSH during the first trimester in Chinese pregnant women? // J Clin Endocrinol Metab. 2014. Vol. 99. Р.73. 5. Morkin, E., Pennock, G.D., Spooner, P.H., Bahl, J.J., Goldman, S., 2002. Clinical and experimental studies on the use of 3,5-diiodothyropropionic acid, a thyroid hormone analogue, in heart failure. Thyroid 12, 527 –533 . 6. Quan, Z. Disi junyi daxue xuebao / Z. Quan, L. Zhi-Liang, W. Su- Hua, L. Qing // J. Forth Milit. Med. Univ. - 2001. - Vol. 22, № 15. _ p. 1388¬1391. 7. Ribeiro, M.O., Carvalho, S.D., Schultz, J.J., Chiellini, G., Scanlan, T.S., Bianco, A.C., Brent, G.A., 2001. Thyroid hormone — sympathetic interaction and adaptive thermogenesis are thyroid hormone receptor isoform —specific. J. Clin. Invest. 108, 97 – 105. 8. Schiros, C.G., Ahmed, M.I., Sanagala, T., Zha, W., Mcgiffin, D.C., Bamman, M.M., Gupta, H., Lloyd, S.G., Denney, T.S.J., Dell'italia, L.J., 2013. Importance of three-dimensional geometric analysis in the assessment of the athlete's heart. Am. J. Cardiol. 111, 1067 – 1072 . 9. Sedmera, D., Thompson, R.P., Kolar, F., 2003. Effect of increased pressure loading on heart growth in neonatal rats. J. Mol. Cell. Cardiol. 35, 301 –309 10. Segar, J.L., Volk, K.A., Lipman, M.H., Scholz, T.D., 2013. Thyroid hormone is required for growth adaptation to pressure load in the ovine fetal heart. Exp. Physiol. 98, p.722– 733. 11. Skřivánek A., Lubušký M., Studničková M. ey al. Epidemiology and management of thyroid disorders in pregnancy // Ceska Gynekol. 2013. Vol. 78 (1). Р.62-67 12. Stagrano-Green A., Abalovich M., Alexander E. et al. Guidline of of the American Thyroid Assosiation for the diagnosis and management of Thyroid disease during pregnancy and postpartum // Thyroid. 2011. Vol. 21 (10). P.1086‒1088. 13. White, P., Burton, K.A., Fowden, A.L., Dauncey, M.J., 2001. Developmental expression analysis of thyroid hormone receptor isoforms reveals new insights into their essential functions in cardiac and skeletal muscles. FASEB J. 15, 1367 – 1376. 14. Yang, X., Rodriguez, M., Pabon, L., Fischer, K.A., Reinecke, H., Regnier, M., Sniadecki, N.J., Ruohola-Baker, H., Murry, C.E., 2014. Tri-iodo-l-thyronine promotes the maturation of human cardiomyocytes-derived from induced pluripotent stem cells. J. Mol. Cell. Cardiol. 72, p. 296 – 304.
Mirsharopov, Utkur M.; Usmonov, Ravshan J.; Teshaev, Octyabr R.; and Mirzamuhamedov, Odil Kh.
"MORPHOLOGICAL CHANGE OF MYOCARDIUM IN HYPOTHYROIDISM,"
Central Asian Journal of Medicine: Vol. 2020
, Article 8.
Available at: https://uzjournals.edu.uz/tma/vol2020/iss1/8