Co-exposure to polystyrene plastic beads and polycyclic aromatic hydrocarbon contaminants in fish gill (RTgill-W1) and intestinal (RTgutGC) epithelial cells derived from rainbow trout (Oncorhynchus mykiss)

Daniel Bussolaro,Stephanie L Wright,Sabine Schnell,Kristin Schirmer,Nicolas R Bury,Volker M Arlt

doi:10.1016/j.envpol.2019.02.066

Abstract

Microscopic plastic (MP) particles are a ubiquitous contaminant in aquatic environments, which may bind hydrophobic chemicals, such as polycyclic aromatic hydrocarbons (PAHs), altering their environmental fate and interactions with biota. Using rainbow trout gill (RTgill-W1) and intestinal (RTgutGC) epithelial cells we investigated the effects of polystyrene microbeads (PS-MBs; 220 nm) on the cyto- and genotoxicity of the environmental pollutants benzo[a]pyrene (BaP) and 3-nitrobenzanthrone (3-NBA) over 48 h (0, 0.1, 1 and 10 μM). The Alamar Blue bioassay, used to assess cytotoxicity, showed that both pollutants significantly decreased cell viability by 10–20% at 10 μM in both cell lines after 48 h whereas PS-MBs (5 or 50 μg mL−1) were non-toxic. Cytotoxicity in cells treated with PS-MBs together with BaP or 3-NBA were similar to those observed after exposure to BaP or 3-NBA alone. Using the formamidopyrimidine-DNA glycosylase (FPG)-modified comet assay 3-NBA, but not BaP, induced DNA damage in RTgutGC cells at 10 μM (∼10% tail DNA in the absence and ∼15% tail DNA in the presence of FPG versus ∼1% in controls), whereas PS-MBs alone showed no detrimental effects. Interestingly, comet formation was substantially increased (∼4-fold) when RTgutGC cells were exposed to PS-MBs (50 μg mL−1) and 10 μM 3-NBA compared to cells treated with 3-NBA alone. Further, using 32P-postlabelling we observed strong DNA adduct formation in 3-NBA-exposed RTgutGC cells (∼900 adducts/108 nucleotides). 3-NBA-derived DNA adduct formation was significantly decreased (∼20%) when RTgutGC cells were exposed to MB and 3-NBA compared to cells treated with 3-NBA alone. Our results show that PS-MBs impact on the genotoxicity of 3-NBA, causing a significant increase in DNA damage as measured by the comet assay in the intestinal cell line, providing proof of principle that MPs may alter the genotoxic potential of PAHs in fish cells.

Highlights

The contamination of the aquatic environment with plastic debris is a globally recognised problem (Moore, 2008; Jambeck et al, 2015)
Our results show that polystyrene microbeads (PS-MBs) impact on the genotoxicity of 3-NBA, causing a significant increase in DNA damage as measured by the comet assay in the intestinal cell line, providing proof of principle that Microscopic plastic (MP) may alter the genotoxic potential of polycyclic aromatic hydrocarbons (PAHs) in fish cells
The present study aimed to evaluate the influence of micro-plastics (220 nm PS-MBs) on the toxicity of BaP and 3NBA in two epithelial cell lines derived from rainbow trout gill and gut tissue, RTgill-W1 and RTgutGC

Summary

Introduction

The contamination of the aquatic environment with plastic debris is a globally recognised problem (Moore, 2008; Jambeck et al, 2015). In recent years microplastics (MPs; defined as 0.1–5000 μm in diameter) have received increased attention because there is an urgent need to assess the risk they pose to the environment and human health (Wright et al, 2013a; Wright and Kelly, 2017). These primarily originate from the breakdown of larger plastic items (Thompson et al, 2004; Roy et al, 2011), potentially down to the nano-scale (Lambert and Wagner, 2016). These particles consist of many different types such as polyethylene terephthalate (PET), polyvinylchloride (PVC), polystyrene (PS), and polypropylene (PP) amongst others (Kanhai et al, 2017)

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Discussion

Conclusion