Heart cardiolipin content in thyroid dis-orders thyrotropin modulates calcium handling and contractility in adult rat cardiac myocytes.

ABRAMOVICI BLASCO A, MARTINEZ C, D ́ANGELO V, LISTA F, BALASZCZUK AM; FERNÁNDEZ MC; ARRECHE N; BURGOS JI, VILAPETROFF M; FELLET AL.

CABA

Congreso; Reunión Anual de Sociedades de Biociencia SAIC. SAI. SAFIS; 2020

Functional mitochondrial network is important to preserve cell viability and cardiac performance in response to thyroid desorder. In the mitochondrial membrane cardiolipin plays an important role in energy metabolism. The aim of this study was to examine: (1) whether thyroid hormones affects cardiac function affecting cardiac calcium handling in young rats and (2) whether this thyroid desorders alters cardiolipin mitochondrial heart content. Male Sprague?Dawley rats weighing approximately 50 g were used in this study and were randomly assigned to one of the three groups: (1) euthyroid rats (received SC injections of 0.9 NaCl (0.1 ml/100 g body weight), (2) hiperthyroid rats (received SC injections of T3, 20ug/100g body weight) and (3) hipothyroid rats (received 0.02% methimazole in drinking wáter). T3 and methimazole treatments were during 60 days. Cardiac myocytes were isolated by collagenase-based enzymatic digestion. Free cytosolic Ca2+, sarcoplasmic-reticulum Ca2+ content, cardiomyocyte shortening and relaxation measurements were performed. Cardiolipin content was measured by TLC. Contractility alterations induced by thyroid disorder were associated with altered free cytosolic and sarcoplasmic-reticulum Ca2+ content. Hormonal deficiencies also altered the time to 50% Ca2+ decay. Cardiomyocyte relaxation as revealed by a reduction in the time to 50% relengthening was also altered in both endocrinal alterations. The number of spontaneous releases per minute was significantly increased in the cardiomyocytes of the hypo and hyper rats. Cardiolipin content was reduced in hipothyroid rats but it was increased in hyperthyroidism. Maintenance of euthyroidism is of crucial importance to preserve cardiac performance. An imbalance in relation to phospholipids of the mitochondrial membrane such as cardiolipin, is related to defects in the mitochondrial function. T3-dependent cardiolipin signals contribute to the maintenance of mitochondrial homeostasis and involved Ca+2 handling.