Inhibition of Xenobiotics Transporters' Efflux Ability after Nanoplastics Exposure in Larval Japanese Medaka

Nanoplastics can enter into the aquatic environment as primary nano-sized or fragmented from larger-sized plastic particles, and their ecological effects and environmental fate have aroused increasing public concerns. Here, we identified the disruption of ATP-binding cassette (ABC) efflux after polystyrene (PS) nanoplastics (76 +/- 7 nm) exposure in larval Japanese medaka (Oryzias latipes). Nanoplastics (0.001-10 mu g/mL) caused 3-6-fold higher lipid peroxidation in fish larvae than the control, with concomitant downregulated expression of efflux transporter-related genes (abcb6a, abcc2, abcg2). Two probes of rhodamine (indicative of p-glycoprotein function for parent compounds' efflux, P-gp) and fluorescein (indicative of multidrug resistance-associated protein function for metabolites' efflux, MRP) were further used to verify the inhibited ABC efflux ability, via rhodamine and fluorescein bioaccumulation results. Three-fold higher accumulation of rhodamine was observed following treatment with 10 mu g/mL of nanoplastics. Excessive accumulation also occurred for fluorescein, with 1.7-1.8-fold higher concentrations than controls in larvae treated with 0.01-0.1 mu g/mL of nanoplastics. Although the inhibition of ABC transporters diminished after two hours of depuration, the co-existence of nanoplastics and other contaminants still raises concerns. Collectively, this study suggests that nanoplastics can negatively impact ABC transporters' efflux ability and could cause unanticipated accumulation of co-existing organic pollutants in aquatic organisms.

Automated summary

This study reveals that nanoplastics can disrupt the ATP-binding cassette (ABC) efflux ability in larval Japanese medaka, leading to increased lipid peroxidation. The inhibited ABC efflux ability was verified through the accumulation of rhodamine and fluorescein. Although the inhibition of ABC transporters diminished after two hours of depuration, the co-existence of nanoplastics and other contaminants still raises concerns.