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Mechanisms of Toxicity of Ag Nanoparticles in Comparison to Bulk and Ionic Ag on Mussel Hemocytes and Gill Cells.

Katsumiti A, Gilliland D, Arostegui I, Cajaraville MP - PLoS ONE (2015)

Bottom Line: Maltose alone provoked minor effects on cell viability.Similar effects were observed after exposure to ionic and bulk Ag in the two cell types, although generally effects were more marked for the ionic form.In conclusion, results suggest that most observed responses were due at least in part to dissolved Ag.

View Article: PubMed Central - PubMed

Affiliation: CBET Research Group, Department of Zoology and Animal Cell Biology, Faculty of Science and Technology and Research Centre for Experimental Marine Biology and Biotechnology PIE, University of the Basque Country UPV/EHU, Plentzia, Spain.

ABSTRACT
Silver nanoparticles (Ag NPs) are increasingly used in many products and are expected to end up in the aquatic environment. Mussels have been proposed as marine model species to evaluate NP toxicity in vitro. The objective of this work was to assess the mechanisms of toxicity of Ag NPs on mussel hemocytes and gill cells, in comparison to ionic and bulk Ag. Firstly, cytotoxicity of commercial and maltose stabilized Ag NPs was screened in parallel with the ionic and bulk forms at a wide range of concentrations in isolated mussel cells using cell viability assays. Toxicity of maltose alone was also tested. LC50 values were calculated and the most toxic Ag NPs tested were selected for a second step where sublethal concentrations of each Ag form were tested using a wide array of mechanistic tests in both cell types. Maltose-stabilized Ag NPs showed size-dependent cytotoxicity, smaller (20 nm) NPs being more toxic than larger (40 and 100 nm) NPs. Maltose alone provoked minor effects on cell viability. Ionic Ag was the most cytotoxic Ag form tested whereas bulk Ag showed similar cytotoxicity to the commercial Ag NPs. Main mechanisms of action of Ag NPs involved oxidative stress and genotoxicity in the two cell types, activation of lysosomal AcP activity, disruption of actin cytoskeleton and stimulation of phagocytosis in hemocytes and increase of MXR transport activity and inhibition of Na-K-ATPase in gill cells. Similar effects were observed after exposure to ionic and bulk Ag in the two cell types, although generally effects were more marked for the ionic form. In conclusion, results suggest that most observed responses were due at least in part to dissolved Ag.

No MeSH data available.


Related in: MedlinePlus

Effects of ionic Ag, bulk Ag and Ag NPs on MXR activity in mussel cells.MXR transport activity in mussel hemocytes and gill cells exposed to ionic Ag (A), bulk Ag (B) and Ag20-Mal NPs (C) for 24 h. Data are given as fluorescence values (means ± confidence intervals). Stars indicate significant differences (p<0.05) in treated cells with respect to controls according to the bootstrap analysis followed by Bonferroni’s correction. n = 6 replicates per treatment.
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pone.0129039.g012: Effects of ionic Ag, bulk Ag and Ag NPs on MXR activity in mussel cells.MXR transport activity in mussel hemocytes and gill cells exposed to ionic Ag (A), bulk Ag (B) and Ag20-Mal NPs (C) for 24 h. Data are given as fluorescence values (means ± confidence intervals). Stars indicate significant differences (p<0.05) in treated cells with respect to controls according to the bootstrap analysis followed by Bonferroni’s correction. n = 6 replicates per treatment.

Mentions: MXR transport activity increased in gill cells exposed to the three forms of Ag while in hemocytes MXR activity increased only in ionic Ag exposure (Fig 12). Ionic Ag increased hemocytes MXR activity at 0.25 and 0.5 mg Ag/L (60% increase) (p<0.05) (Fig 12A). In gill cells, MXR activity increased when exposed to concentrations starting at 0.06 mg Ag/L (30–59% increase) (p<0.05) (Fig 12A). Bulk Ag increased gill cells MXR activity at 0.62 mg Ag/L and then at 5 and 10 mg Ag/L (16–42% increase) (p<0.05) (Fig 12B). Ag20-Mal NPs increased gill cells MXR activity at concentrations starting at 0.31 mg Ag/L (14–35% increase) (p<0.05) (Fig 12C).


Mechanisms of Toxicity of Ag Nanoparticles in Comparison to Bulk and Ionic Ag on Mussel Hemocytes and Gill Cells.

Katsumiti A, Gilliland D, Arostegui I, Cajaraville MP - PLoS ONE (2015)

Effects of ionic Ag, bulk Ag and Ag NPs on MXR activity in mussel cells.MXR transport activity in mussel hemocytes and gill cells exposed to ionic Ag (A), bulk Ag (B) and Ag20-Mal NPs (C) for 24 h. Data are given as fluorescence values (means ± confidence intervals). Stars indicate significant differences (p<0.05) in treated cells with respect to controls according to the bootstrap analysis followed by Bonferroni’s correction. n = 6 replicates per treatment.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4465040&req=5

pone.0129039.g012: Effects of ionic Ag, bulk Ag and Ag NPs on MXR activity in mussel cells.MXR transport activity in mussel hemocytes and gill cells exposed to ionic Ag (A), bulk Ag (B) and Ag20-Mal NPs (C) for 24 h. Data are given as fluorescence values (means ± confidence intervals). Stars indicate significant differences (p<0.05) in treated cells with respect to controls according to the bootstrap analysis followed by Bonferroni’s correction. n = 6 replicates per treatment.
Mentions: MXR transport activity increased in gill cells exposed to the three forms of Ag while in hemocytes MXR activity increased only in ionic Ag exposure (Fig 12). Ionic Ag increased hemocytes MXR activity at 0.25 and 0.5 mg Ag/L (60% increase) (p<0.05) (Fig 12A). In gill cells, MXR activity increased when exposed to concentrations starting at 0.06 mg Ag/L (30–59% increase) (p<0.05) (Fig 12A). Bulk Ag increased gill cells MXR activity at 0.62 mg Ag/L and then at 5 and 10 mg Ag/L (16–42% increase) (p<0.05) (Fig 12B). Ag20-Mal NPs increased gill cells MXR activity at concentrations starting at 0.31 mg Ag/L (14–35% increase) (p<0.05) (Fig 12C).

Bottom Line: Maltose alone provoked minor effects on cell viability.Similar effects were observed after exposure to ionic and bulk Ag in the two cell types, although generally effects were more marked for the ionic form.In conclusion, results suggest that most observed responses were due at least in part to dissolved Ag.

View Article: PubMed Central - PubMed

Affiliation: CBET Research Group, Department of Zoology and Animal Cell Biology, Faculty of Science and Technology and Research Centre for Experimental Marine Biology and Biotechnology PIE, University of the Basque Country UPV/EHU, Plentzia, Spain.

ABSTRACT
Silver nanoparticles (Ag NPs) are increasingly used in many products and are expected to end up in the aquatic environment. Mussels have been proposed as marine model species to evaluate NP toxicity in vitro. The objective of this work was to assess the mechanisms of toxicity of Ag NPs on mussel hemocytes and gill cells, in comparison to ionic and bulk Ag. Firstly, cytotoxicity of commercial and maltose stabilized Ag NPs was screened in parallel with the ionic and bulk forms at a wide range of concentrations in isolated mussel cells using cell viability assays. Toxicity of maltose alone was also tested. LC50 values were calculated and the most toxic Ag NPs tested were selected for a second step where sublethal concentrations of each Ag form were tested using a wide array of mechanistic tests in both cell types. Maltose-stabilized Ag NPs showed size-dependent cytotoxicity, smaller (20 nm) NPs being more toxic than larger (40 and 100 nm) NPs. Maltose alone provoked minor effects on cell viability. Ionic Ag was the most cytotoxic Ag form tested whereas bulk Ag showed similar cytotoxicity to the commercial Ag NPs. Main mechanisms of action of Ag NPs involved oxidative stress and genotoxicity in the two cell types, activation of lysosomal AcP activity, disruption of actin cytoskeleton and stimulation of phagocytosis in hemocytes and increase of MXR transport activity and inhibition of Na-K-ATPase in gill cells. Similar effects were observed after exposure to ionic and bulk Ag in the two cell types, although generally effects were more marked for the ionic form. In conclusion, results suggest that most observed responses were due at least in part to dissolved Ag.

No MeSH data available.


Related in: MedlinePlus