Comparative oxygen radical formation and toxicity of BDE 47 in rainbow trout cell lines

Abstract

The polybrominated diphenyl ethers (PBDEs) constitute a class of flame retardants whose residues have markedly increased in fish and human tissues during the last decade. In particular, the levels of certain PBDE congeners in salmon have raised concern regarding potential risks associated with dietary PBDE exposures. However, little is known regarding PBDE-mediated cell injury in relevant in vitro cell models. We conducted a comparative study of oxyradical production and cell injury in rainbow trout gill (RTgill-W1) and trout liver cells (RTL-W1) exposed to 2,2′,4,4′-tetrabromodiphenyl ether (BDE 47), a predominant BDE residue found in fish tissues such as salmonids. Exposure to low micromolar concentrations of BDE 47 elicited a significant loss in RTgill-W1 and RTL-W1 cell viability as measured by alamarBlue assay. The dose-response of BDE toxicity differed among the two cell lines, with the RTL-W1 liver cells showing greater resistance to toxicity at lower BDE 47 doses, but a more dramatic loss of viability relative to gill cells when challenged with higher (50 μM) doses. The sensitivity of the trout liver cells at higher BDE 47 exposures was reflected by a higher basal production of oxygen radical production by 6-carboxy-2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescence that was markedly enhanced in the presence of BDE 47, suggesting an overwhelming of trout liver cell antioxidant defense pathways. Collectively, our data indicate that RTgill-W1 and RTL-W1 liver cells are sensitive to BDE 47-mediated cell injury through a mechanism that may involve oxidative stress. Our data also provide an in vitro basis for potential tissue differences in BDE 47-mediated cell injury.

Developmental retardation, reduced fecundity, and modulated expression of the defensome in the intertidal copepod Tigriopus japonicus exposed to BDE-47 and PFOS

“…In copepods, radiation (e.g., UV and gamma ray), endocrine disrupting chemicals (EDCs), and metals induced repercussions on the life cycle and reproduction associated with an increase in ROS levels in both T. japonicus (Han et al, 2014a,b) and Paracyclopina nana . BDE-47 also induced ROS in a rainbow trout cell line and tissues of the mussel Mytilus galloprovincialis (Shao et al, 2008;Ji et al, 2013), whereas PFOS induced ROS in the freshwater tilapia Oreochromis niloticus and the zebrafish embryo (Liu et al, 2007;Shi and Zhou, 2010). The induction of ROS by BDE-47 and PFOS in T. japonicus had adverse effects on normal growth and reproduction.…”

Applications and potential uses of fish gill cell lines: examples with RTgill-W1

“…Most recently, Bopp et al (2008) used RTgill-W1 cells to further evaluate toxicity of copper and hypothesized that copperinduced loss in viability and genotoxicity in trout gills may partially be triggered by the generation of reactive oxygen species. Similarly, the toxicity of polibrominated diphenyl ethers (PBDEs) when tested with RTgill-W1 (Shao et al 2008) as well as with the trout liver cell line RTL-W1, suggest that these compounds mediate cell injury through a mechanism that may involve oxidative stress.…”

PBDE flame retardants

“…While these are often the primary endpoints of focus, other toxicity outcomes have been observed in fish as well, including immunotoxicity 42,43 and oxidative stress. [44][45][46] The PentaBDE commercial mixture and its component congeners have been the subject of most study to date, with less known about the toxicity of BDE-209 and the other higher MW PBDE congeners. However, BDE-209 is the only PBDE that has been evaluated for carcinogenicity with "suggestive evidence of carcinogenic potential" based on increased thyroid cell hyperplasia and thyroid adenomas/carcinomas in male mice and liver tumors in male rats.…”