Combined effects of nonylphenol and bisphenol a on the human prostate epithelial cell line RWPE-1.

Weidong Gan,Dongmei Li,Ming Zhou,Xiaodong Han,Zou Xiang

doi:10.3390/ijerph120404141

Abstract

The xenoestrogens nonylphenol (NP) and bisphenol A (BPA) are regarded as endocrine disrupting chemicals (EDCs) which have widespread occurrence in our daily life. In the present study, the purpose was to analyze the combined effects of NP and BPA on the human prostate epithelial cell line RWPE-1 using two mathematical models based on the Loewe additivity (LA) theory and the Bliss independence (BI) theory. RWPE-1 cells were treated with NP (0.01–100 µM) and BPA (1–5000 µM) in either a single or a combined format. A cell viability assay and lactate dehydrogenase (LDH) leakage rate assay were employed as endpoints. As predicted by the two models and based on the cell viability assay, significant synergism between NP and BPA were observed. However, based on the LDH assay, the trends were reversed. Given that environmental contaminants are frequently encountered simultaneously, these data indicated that there were potential interactions between NP and BPA, and the combined effects of the chemical mixture might be stronger than the additive values of individual chemicals combined, which should be taken into consideration for the risk assessment of EDCs.

Highlights

It is known that all living organisms are constantly and unavoidably exposed to a variety of synthetic chemicals through food, air, water and dermal contact
The toxicity ranking for the individual contaminant is NP > Bisphenol A (BPA), with NP being at least 30 times more active in the assay than BPA
The viability assay and lactate dehydrogenase (LDH) leakage rate assay were chosen as two endpoints for a sensible testing approach because both assays provided reproducible quantitative data with relatively few variations and could detect small changes among different dose-groups, which makes the assessment more credible and precise

Summary

Introduction

It is known that all living organisms are constantly and unavoidably exposed to a variety of synthetic chemicals through food, air, water and dermal contact. BPA has been widely used for its cross-linking properties in the manufacture of polycarbonate plastics and epoxy resins. Because of incomplete polymerization and degradation of the polymers, BPA has been found to leach in microgram amounts from polycarbonate plastics and epoxy resins into food and water supplies [2]. Exposure to NP and BPA is nearly ubiquitous, and urinary analysis revealed that NP was detected in 51% of the samples from a population of 394 adults and BPA is detected in >93% of the population in the United States [3,4] The human body is exposed to concentration of 7.5 μg/day of NP and 10 μg/kg/day BPA in the way which they leach from the lining of plastic packages, cans and baby bottles, and pipe walls [3,5]

Methods

Results

Conclusion