Chronic PFOS Exposure Disrupts Thyroid Structure and Function in Zebrafish

Perfluorooctane sulfonic acid (PFOS), as a potential endocrine disrupting chemical, is widely detected in the environment, wildlife and human. Currently few studies have documented the effects of chronic PFOS exposure on thyroid in aquatic organisms and the underlying mechanisms are largely unknown. The present study assessed the effect of chronic PFOS exposure on thyroid structure and function using zebrafish model. Zebrafish at 8 h post fertilization (hpf) were exposed to PFOS (250 µg/l) until 120 d post fertilization (dpf). Thyroid hormone (T₃ and T₄) level, thyroid morphology and thyroid function related gene expression were evaluated in zebrafish at 120 dpf. Our findings demonstrated that chronic PFOS exposure altered thyroid hormone level, thyroid follicular cell structure and thyroid hormone related gene expression, suggesting the validity of zebrafish as an alternative model for PFOS chronic toxicity screening.