A Comparative Genotoxicity Study of a Supraphysiological Dose of Triiodothyronine (T-3) in Obese Rats Subjected to Either Calorie-Restricted Diet or Hyperthyroidism

Autor(es)

De Sibio, Maria Teresa ^[1] ; Melo Luvizotto, Renata Azevedo ^[1] ; Castro Olimpio, Regiane Marques ^[1] ; Correa, Camila Renata ^[2] ; Marino, Juliana ^[1] ; de Oliveira, Miriane ^[1] ; Conde, Sandro Jose ^[1] ; dos Anjos Ferreira, Ana Lucia ^[1] ; Padovani, Carlos Roberto ^[3] ; Nogueira, Celia Regina ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo State UNESP, Botucatu Med Sch, Dept Internal Med, Botucatu, SP - Brazil

^[2] Univ Sao Paulo State UNESP, Botucatu Med Sch, Dept Pathol, Botucatu, SP - Brazil

^[3] Univ Sao Paulo State UNESP, Biosci Inst, Dept Biostat, Botucatu, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 8, n. 2 FEB 28 2013.
• Citações Web of Science: 10

Resumo

This study was designed to determine the genotoxicity of a supraphysiological dose of triiodothyronine (T-3) in both obese and calorie-restricted obese animals. Fifty male Wistar rats were randomly assigned to one of the two following groups: control (C; n = 10) and obese (OB; n = 40). The C group received standard food, whereas the OB group was fed a hypercaloric diet for 20 weeks. After this period, half of the OB animals (n = 20) were subjected to a 25%-calorie restriction of standard diet for 8 weeks forming thus a new group (OR), whereas the remaining OB animals were kept on the initial hypercaloric diet. During the following two weeks, 10 OR animals continued on the calorie restriction diet, whereas the remaining 10 rats of this group formed a new group (ORS) given a supraphysiological dose of T-3 (25 mu g/100 g body weight) along with the calorie restriction diet. Similarly, the remaining OB animals were divided into two groups, one that continued on the hypercaloric diet (OB, n = 10), and one that received the supraphysiological dose of T-3 (25 mu g/100 g body weight) along with the hypercaloric diet (OS, n = 10) for two weeks. The OB group showed weight gain, increased adiposity, insulin resistance, increased leptin levels and genotoxicity; T-3 administration in OS animals led to an increase in genotoxicity and oxidative stress when compared with the OB group. The OR group showed weight loss and normalized levels of adiposity, insulin resistance, serum leptin and genotoxicity, thus having features similar to those of the C group. On the other hand, the ORS group, compared to OR animals, showed higher genotoxicity. Our results indicate that regardless of diet, a supraphysiological dose of T-3 causes genotoxicity and potentiates oxidative stress. (AU)

• Processo FAPESP: 08/57310-3 - Efeito de diferentes doses de hormonios tireoidianos sobre dano de dna e expressao genica e proteica do transito de calcio em animais obesos e sumetidos a restricao calorica
• Beneficiário: Celia Regina Nogueira
• Modalidade de apoio: Auxílio à Pesquisa - Regular