Effects of physical exercise and thyroid hormone on myosin heavy chain expression in doxorubicin‐induced cardiotoxicity in rats

• Published in: The FASEB journal Vol. 30; no. S1
• Main Authors: Campos, Erica C, Souza, Fernanda R, Freitas, Ana C S, Ramos, Simone G, Resende, Elmiro S
• Format: Journal Article
• Language: English
• Published: 01-04-2016
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.30.1_supplement.1178.3

Abstract only
The cardiomyocytes membrane integrity and the presence of structural proteins play an essential role for cellular function. The structural proteins that maintain the sarcolemma integrity has been associated with cardiotoxic effects of doxorubicin, as example, the loss of actin‐myosin interaction. Two therapeutic options could be used to minimize the deleterious effects of cardiotoxic effects in contractile apparatus: the use of thyroid hormone and exercise. For analysis of myosin expression the animals were divided into seven groups identified as: control (C), exercise control (EC), thyroid hormone control (CHT), doxorubicin control (CDX), hormone and doxorubicin (HTDX), exercise and doxorubicin (EDX) and the hormone plus exercise and doxorubicin (HTEDX). The animals received intraperitoneal injections of doxorubicin hydrochloride three times a week, for two weeks, reaching a cumulative dose of 7.5 mg / kg. To the CHT groups, and HTDX HTEDX hormone was administered daily for four weeks, by oro gastric probe. The dose was 10 mg / 100g body weight. CE groups, EDX and HTEDX performed exercise. The swimming exercise was used, and with additional cumulative loading up to 5% of body weight. The training was conducted for 4 weeks with three weekly sessions of swimming. The expression of myosin heavy chain evaluated by Western blotting showed increase in myosin expression in HTDX and HTEDX groups. The results suggest that exposure to higher doses of thyroid hormone significantly increases the expression of myosin both in the presence and absence of exercise. Additional effects of exercise can contribute to other favorable results in cardiovascular system.
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