Thyroxine replacement modifies changes in deiodinase and thyroid hormone transporter expression induced by subclinical hypothyroidism in rats

Autor(es)

Oliveira, Kelen Carneiro ; Laureano-Melo, Roberto ; da Conceicao, Rodrigo Rodrigues ; de Souza, Janaina Sena ; da Silva Cortes, Wellington ; Sato, Monica Akemi ; Chiamolera, Maria Izabel ; Maciel, Rui Monteiro ; Giannocco, Gisele

• Tipo de documento: Artigo Científico
• Fonte: HORMONES-INTERNATIONAL JOURNAL OF ENDOCRINOLOGY AND METABOLISM; v. 20, n. 1, p. 10-pg., 2020-09-29.

Resumo

Purpose The potential benefits of treating subclinical hypothyroidism (SCH) are unclear and still controversial. Thus, we surgically induced SCH in rats and evaluated the effects of thyroxine (T-4) replacement on the gene expression levels of deiodinases and thyroid hormone (TH) transporters in different tissues. Methods SCH was induced by hemithyroid electrocauterization. The control animals underwent the same surgical procedure but were not subjected to electrocauterization (sham). After 14 days, half of the SCH animals were treated with T-4(SCH + T-4). At the end of the experimental protocol, all of the rats were euthanized, serum hormone concentrations were measured, and RNA analyses were performed on different tissues and organs. Results Consistent with previous studies, we observed increased TSH levels, normal TH levels, and reduced hypothalamic TRH expression in the SCH group. Additionally, Dio2 mRNA expression was downregulated in the hippocampus and pituitary, and Dio1 was upregulated in the kidney and pituitary of the SCH animals. The changes in Dio3 expression were tissue-specific. Concerning TH transporters, Mct10 expression was upregulated in the pituitary, kidney, hypothalamus, and hippocampus, and Mct8 expression was downregulated in the kidney of the SCH group. Crym expression was upregulated in the kidney and pituitary. Notably, T(4)replacement significantly attenuated serum TSH levels and reverted Dio1, Dio2, Mct10, and Crym expression in the pituitary, hippocampus, and kidney to levels that were similar to the sham group. Tissue-specific responses were also observed in the liver and hypothalamus. Conclusion Our results indicate that treatment of SCH should be considered before the appearance of clinical symptoms of hypothyroidism. (AU)

• Processo FAPESP: 17/23169-1 - Efeito dos hormônios tiroidianos no encéfalo de camundongos 3xTg-AD (APPswe, PS1m146v, tauP301L) modelo da doença de Alzheimer
• Beneficiário: Gisele Giannocco
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 18/22763-0 - DNA antigo, bioengenharia e "organoides" de cérebro: estudo da homeostase do hormônio tiroidiano e marcadores da Doença de Alzheimer em células tronco com gene NOVA1 editado por CRISPR
• Beneficiário: Janaína Sena de Souza
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado
• Processo FAPESP: 17/07053-3 - Efeito do hormônio tiroidiano no encéfalo de camundongos 3xTg-AD, modelo da Doença de Alzheimer, no metabolismo da glicose e colesterol
• Beneficiário: Janaína Sena de Souza
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado