In vivo exposure of the marine clam Ruditapes philippinarum to zinc oxide nanoparticles: responses in gills, digestive gland and haemolymph.
Potential nanoparticle (NP) toxicity poses a growing concern in marine coastal environments. Among NPs, zinc oxide nanoparticles (nZnO) are widely used in many common products that ultimately become deposited in coastal habitats from multiple non-point sources. In this study, we evaluated the in vivo effects of nZnO in the clam Ruditapes philippinarum. Animals were exposed to nZnO (1 and 10 μg/L) and ZnCl2 (10 μg/L) for 7 days. ZnCl2 was used to compare the effects of the NPs to those of Zn(2+) and to ascertain whether nZnO toxicity is attributable to the release of ions into the aquatic medium. At differing time intervals during the exposure, several biochemical and cellular responses were evaluated in the clam gills, digestive gland, and haemolymph. The results showed that nZnO, at concentrations close to the predicted environmental levels, significantly affected various parameters in clam tissues. Significant increases in catalase and superoxide dismutase activities and a decreasing trend of glutathione S-transferase activity indicated the involvement of oxidative stress in nZnO toxicity. In clams exposed to ZnCl2, slight variations in antioxidant enzyme activities were detected with respect to nZnO-treated clams. However, no damage to lipids, proteins or DNA was revealed in all exposure conditions, suggesting a protection of antioxidant enzymes in the tissues. Of the various haemolymph parameters measured, haemocyte proliferation increased significantly, in ZnCl2-treated clams in particular. Under nZnO (10 μg/L) and ZnCl2 exposure, DNA damage in haemocytes was also revealed, but it was lower in clams exposed to ZnCl2. A decreasing trend in gill AChE activity of treated clams proposed a possible role of zinc ions in nZnO toxicity. However, the dissimilar modulation of the responses in the nZnO- and ZnCl2-exposed clams suggested different mechanisms of action, with nZnO toxicity possibly depending not only on the release of zinc ions but also on NP-specific features. Changes in the biological parameters measured in the clams were consistent with Zn accumulation in their gills and digestive glands.
Department of Biology, University of Padua, Via Ugo Bassi 58/B, 35131, Padua, Italy.
Ilaria
I
Marisa
Department of Biology, University of Padua, Via Ugo Bassi 58/B, 35131, Padua, Italy.
Valerio
V
Matozzo
Department of Biology, University of Padua, Via Ugo Bassi 58/B, 35131, Padua, Italy.
Marco
M
Munari
Department of Biosciences, University of Milan, Via Celoria 26, 20133, Milan, Italy.
Andrea
A
Binelli
Department of Biosciences, University of Milan, Via Celoria 26, 20133, Milan, Italy.
Marco
M
Parolini
Industrial Engineering Department and INSTM, University of Padua, Via Marzolo 9, 35131, Padua, Italy.
Alessandro
A
Martucci
Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Via Marzolo 5, 35131, Padua, Italy.
Erica
E
Franceschinis
Institute for Energetics and Interphases (IENI), CNR, Corso Stati Uniti 4, 35127, Padua, Italy.
Nicola
N
Brianese
Department of Biology, University of Padua, Via Ugo Bassi 58/B, 35131, Padua, Italy. mgmar@bio.unipd.it.
Maria Gabriella
MG
Marin
D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D049872:Bivalvia / Q000187:drug effects* / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D049109:Cell Proliferation; D002712:Chlorides / Q000633:toxicity; D053938:DNA Fragmentation; D004064:Digestive System / Q000187:drug effects / Q000378:metabolism; D005880:Gills / Q000187:drug effects / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006458:Hemolymph / Q000378:metabolism; D015227:Lipid Peroxidation; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D018384:Oxidative Stress; D010316:Particle Size; D050050:Protein Carbonylation; D013482:Superoxide Dismutase / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*; D017967:Zinc Compounds / Q000633:toxicity; D015034:Zinc Oxide / Q000737:chemistry / Q000633:toxicity*
D002712:Chlorides; D014874:Water Pollutants, Chemical; D017967:Zinc Compounds; C016837:zinc chloride; D002374:Catalase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D000110:Acetylcholinesterase; D015034:Zinc Oxide
Bioaccumulation; Biomarkers; Clams; Nanoparticles; Zinc; Zinc oxide nanoparticles