Effects of polymer-coated metal oxide nanoparticles on goldfish (Carassius auratus L.) neutrophil viability and function

Abstract

Exposure effects from polyacrylic acid (PAA) metal-oxide nanoparticles (TiO₂, CeO₂, Fe₂O₃, ZnO) on fish neutrophil viability and effector functions (degranulation, respiratory burst, inflammatory gene expression) were investigated using primary kidney goldfish (Carassius auratus L.) neutrophils as a model. Several studies have reported cytotoxic effects of NPs but there are limited reports on their potential to perturb the innate immune system of aquatic organisms. PAA-TiO₂ significantly decreased neutrophil viability in a time and dose-dependent manner at all measured time points (0–48 h) and concentrations (0–200 µg/mL). Maximum viability decreased by (mean ± SEM): 67.1 ± 3.3%, 78.4 ± 4.2% and 74.9 ± 5.0% when exposed to 50, 100 and 200 µg/mL for 48 h, respectively. PAA-ZnO also significantly decreased neutrophil viability but only at 48 h exposures at higher concentrations. Neutrophil degranulation increased by approximately 3% after 30 min and by 8% after 4 h when exposed to sublethal doses (10 µg/mL) of PAA-CeO₂ or PAA-Fe₂O₃. All PAA-NPs induced an increase in neutrophil respiratory burst when exposed to 10 µg/mL for 30 and 60 min, however, PAA-Fe₂O₃ was the only NP where the response was significant. Lastly, NPs altered the expression of a number of pro-inflammatory and immune genes, where PAA-TiO₂ most significantly increased the mRNA levels of pro-inflammatory genes (il-1b, ifng) in neutrophils by 3 and 2.5 times, respectively. Together, these data demonstrate that goldfish neutrophils can be negatively affected from exposures to PAA-coated NPs and are functionally responsive to specific core-material properties at sublethal doses. These changes could perturb the innate response and affect the ability of fish to respond to pathogens.

• Degranulation
• immunotoxicology
• inflammation
• respiratory burst
• toxicology

Acknowledgements

Authors thank Dr. D. Boyle for critical comments on the manuscript, Dr. M. Iqbal for providing TEM images of the PAA-NPs and Dr. Jon Veinot for access to NP characterization equipment.

Declaration of interest

The authors declare that there is no conflict of interest.

This work was supported by grants from the Natural Sciences and Engineering Research Council (NSERC) of Canada to JLS, MB and GGG and the NNBNI Environment Canada, and NRC Nanotechnology Initiative (Grant #RES0002319) to JLS and GGG as well as the Alberta Innovates Technology Futures nanoWorks collaborative research agreement (CRA Reference #200900065) to GGG. BAK was supported by NSERC and Alberta Innovates doctoral scholarships. VAO was supported by NSERC post-graduate doctoral scholarship

Supplementary material available online

Supplementary Table S1

Supplementary Figures S1–S2