Work

Methyl and propylparaben elicit distinct thyroid-disrupting effects in a rat thyroid cell model

Year: 2025

Type: article

Abstract: Parabens, including methylparaben (MtP) and propylparaben (PrP), are synthetic preservatives commonly used in cosmetics and personal care products. Increasing evidence suggests that these compounds may act as endocrine-disrupting chemicals (EDCs), but their effects on thyroid function remain incompletely understood. This study aimed to investigate the impact of MtP and PrP on cell viability, proliferation, oxidative stress, thyroid-related gene expression, genotoxicity, and effects on cAMP in differentiated FRTL-5 rat thyroid cells. FRTL-5 cells were treated with MtP or PrP at concentrations of 0, 0.001, 0.01, 0.1, 1, 10, and 100 μg/ml for 24, 48, and 72 hours. Cell viability and proliferation were assessed by WST-1 and crystal violet assays, respectively. Reactive oxygen species (ROS) generation was measured using a DCFDA-based fluorescence assay. Gene expression of thyroid-related genes ( TG , TSHR , NIS , NKX2-1 , PAX8 , TPO ) was quantified by real-time PCR. Micronuclei formation was evaluated as a marker of genotoxicity. Intracellular cAMP levels were measured using an ELISA-based method. PrP at 100 μg/ml significantly reduced cell viability (after 72 hours) and proliferation (after 48–72 hours) at difference with MtP. Both PrP 100 μg/ml and MtP 10–100 μg/ml increased ROS levels. PrP and MtP induced complex, dose-dependent, and non-monotonic changes in gene expression. Notably, PrP 10 μg/ml upregulated most thyroid-related genes, while PrP 100 μg/ml suppressed them. cAMP levels increased significantly with PrP 100 μg/ml. No significant genotoxicity was observed. In conclusion, MtP and PrP exert different effects on thyroid cells, supporting their potential role as thyroid-disrupting chemicals.

Source: Emerging contaminants

DOI: 10.1016/j.emcon.2025.100592