Protection and safety of a repeated dosage of KI for iodine thyroid blocking during pregnancy

Hayat Gaouaoui-Azouaou (1) , Bruno L'Homme (1) , Mohamed‐amine Benadjaoud (2) , Amandine Sache-Aloui (3) , Romain Granger (3) , Frederic Voyer (3) , Philippe Lestaevel (4) , Gaëtan Gruel (1) , François Caire-Maurisier (5) , Caroline Crambes (5) , Stephanie Dare-Doyen (2) , Marc Benderitter (6) , Maâmar Souidi (1)

1 IRSN/PSE-SANTE/SERAMED/LRAcc - Laboratoire de Radiobiologie des expositions accidentelles
2 IRSN/PSE-SANTE/SERAMED - Service de recherche en radiobiologie et en médecine régénérative
3 IRSN/PSE-SANTE/SESANE/GSEA - Groupe de support à la recherche et à l'éthique animale
4 IRSN/PSE-SANTE/SER/BASEP - Bureau d'analyse et de suivi des expositions professionnelles
5 PCA - Pharmacie Centrale des Armées (PCA), Direction des Approvisionnements en produits de Santé des Armées, Fleury-les-Aubrais, 45404, France
6 IRSN/PSE-SANTE - Pôle Santé Environnement - Direction Santé

In case of nuclear power plant accidents resulting in the release of radioactive iodine (131 I) in large amounts, a single intake of stable iodine is recommended in order to prevent 131 I fixation to the thyroid gland. However, in situations of prolonged exposure to 131 I (e.g. Fukushima-Daiichi natural and nuclear disaster), repetitive administration of iodine may be necessary to ensure adequate protection, with acceptable safety in vulnerable populations including pregnant women. Here we conducted toxicological studies on adult rats progeny following prolonged exposure to potassium iodide (KI) in utero. Pregnant Wistar rats were treated with 1 mg kg d −1 KI or saline water for 2 or 4 d either between gestation days gestational day (GD) GD 9-12, or GD13-16. Plasma samples from the progeny were tested 30 d post-weaning for clinical biochemistry, thyroid hormones, and anti-thyroid antibody levels. Thyroid and brain were collected for gene expression analysis. The hormonal status was similar for the mothers in all experimental conditions. In the offspring, while thyroid-stimulating hormone and anti-thyroid peroxidase (anti-TPO) antibody levels were similar in all groups, a significant increase of FT3 and FT4 levels was observed in GD9-GD10 and in GD13-GD14 animals treated for 2 d, respectively. In addition, FT4 levels were mildly decreased in 4 d treated GD13-16 individuals. Moreover, a significant decrease in the expression level of thyroid genes involved in iodide metabolism, TPO and apical iodide transporter, was observed in GD13-GD14 animals treated for 2 d. We conclude that repeated KI administration for 2-4 d during gestation did not induce strong thyroid toxicity.

Mots clés: potassium iodine; gestation; thyroid hormones; progeny; nuclear accident; iodine thyroid blocking

Domaines: Sciences du Vivant [q-bio]

Hayat Gaouaoui-Azouaou, Bruno L'Homme, Mohamed‐amine Benadjaoud, Amandine Sache-Aloui, Romain Granger, et al.. Protection and safety of a repeated dosage of KI for iodine thyroid blocking during pregnancy. Journal of Radiological Protection, 2022, 42, pp.011512. ⟨10.1088/1361-6498/ac336e⟩. ⟨irsn-04166326⟩