Maternal Exposure to Iodine Excess Throughout Pregnancy and Lactation Induces Hypothyroidism in Adult Male Rat Offspring

Author(s)

Serrano-Nascimento, Caroline ^[1] ; Salgueiro, Rafael Barrera ^[1] ; Pantaleao, Thiago ^[2] ; Correa da Costa, Vania Maria ^[2] ; Nunes, Maria Tereza ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, Sao Paulo - Brazil

^[2] Univ Fed Rio de Janeiro, Carlos Chagas Filho Biophys Inst, Rio De Janeiro - Brazil

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 7, NOV 15 2017.
• Web of Science Citations: 6

Abstract

This study aimed to investigate the consequences of maternal exposure to iodine excess (IE; 0.6 mg NaI/L) throughout pregnancy and lactation on the hypothalamus-pituitary-thyroid axis of the male offspring in adulthood. Maternal IE exposure increased hypothalamic Trh mRNA expression and pituitary Tsh expression and secretion in the adult male offspring. Moreover, the IE-exposed offspring rats presented reduced thyroid hormones levels, morphological alterations in the thyroid follicles, increased thyroid oxidative stress and decreased expression of thyroid differentiation markers (Tshr, Nis, Tg, Tpo, Mct8) and thyroid transcription factors (Nkx2.1, Pax8). Finally, the data presented here strongly suggest that epigenetic mechanisms, as increased DNA methylation, augmented DNA methyltransferases expression, hypermethylation of histone H3, hypoaceylation of histones H3 and H4, increased expression/activity of histone deacetylases and decreased expression/activity of histone acetyltransferases are involved in the repression of thyroid gene expression in the adult male offspring. In conclusion, our results indicate that rat dams' exposure to IE during pregnancy and lactation induces primary hypothyroidism and triggers several epigenetic changes in the thyroid gland of their male offspring in adulthood. (AU)

• FAPESP's process: 12/24391-6 - Impact of iodine excess exposure during pregnancy and/or lactation on the hypothalamus-pituitary-thyroid axis activity in rat dams and their offspring
• Grantee: Caroline Serrano Do Nascimento
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/05629-4 - Genomic vs nongenomic actions of thyroid hormones: changes of paradigms, physiological implications and therapeutical perspectives
• Grantee: Maria Tereza Nunes
• Support Opportunities: Research Projects - Thematic Grants