Relevant dose of the environmental contaminant, tributyltin, promotes histomorphological changes in the thyroid gland of male rats

• Published in: Molecular and cellular endocrinology 2020-02, Vol.502, p.110677-110677, Article 110677
• Main Authors: Rodrigues-Pereira, Paula, Macedo, Sofia, Gaspar, Tiago Bordeira, Canberk, Sule, Selmi-Ruby, Samia, Máximo, Valdemar, Soares, Paula, Miranda-Alves, Leandro
• Format: Article
• Language: English
• Subjects: Environmental relevant concentration; Environmental relevant dose; Histology; Morphology; Morphometry; Thyroid; Tributyltin
• ISSN: 0303-7207; 1872-8057
• DOI: 10.1016/j.mce.2019.110677

Organotin compounds, such as tributyltin (TBT), are common environmental contaminants and suspected endocrine-disrupting chemicals. Tributyltin is found in antifouling paints, widely used in ships and other vessels. The present study evaluated whether a 15-day treatment with TBT at a dose of 100 ng/kg/day could induce histomorphological changes in the thyroid gland of rats. TBT promoted relevant alterations in the thyroid architecture, being the most relevant histological findings the presence of increased number of small-size follicles in the treated group. In qualitative analyses, colloid vacuolization, papillary budging structures, cystic degeneration and chronic thyroiditis, were observed. Moreover, histomorphometric analysis showed statistically significant changes in the follicular architecture of TBT-treated rats, mainly a decrease in the follicle area (colloid) and an increased epithelial height that resulted in an increased epithelial height/colloid ratio. Augmented collagen deposition was also seen in the thyroids of treated groups. In immunohistochemical (IHC) analyses, the localization of NIS protein was described and a significant increased proliferation index (evaluated by Ki67 positive cells) in the treated group was reported. As an indirect measurement of oxidative stress, mitochondrial protein SDHA was also analyzed by IHC analysis. Although the cytoplasmic expression of SDHA was observed in both groups, the staining intensity score was higher in TBT-treated group. Our results suggest that besides causing histomorphological changes, environmental relevant dose of TBT treatment can also induce oxidative alterations. •Subacute exposure to low dose of TBT promoted alterations in the thyroid cytoarchitecture.•Subacute exposure to low dose of TBT caused a significant increase of interstitial collagen deposition.•Thyrocytes proliferation index was increased and expression of SDHA was higher in TBT-treated group.