Bioavailability and Immunotoxicity of Silver Nanoparticles to The Freshwater MusselElliptio complanata

Abstract

The purpose of this study was to examine the effects of Ag nanoparticles (nAg) of two different sizes (20 and 80 nm) and Ag(+) on the immune system of the freshwater mussel Elliptio complanata. Mussels were exposed to increasing concentrations of nAg and dissolved Ag (AgNO3) for 48 h at 15°C and concentration of 0, 0.8, 4, or 20 μg/L. Immunocompetence was determined by hemocyte viability, phagocytosis, and cell cytotoxicity. Ag tissue loadings and levels of metallothioneins (MT), lipid peroxidation (LPO), and labile zinc (Zn) were also determined. Results revealed first that 20- and 80-nm nAg readily formed aggregates in freshwater. Ag was detected in soft tissues with each form of Ag with bioconcentration factors of 20, 9, and 7 for Ag(+), 20-nm nAg, and 80-nm nAg, respectively. Significant induction in phagocytosis and decreased cell cytotoxicity were observed. All forms of Ag were able to induce LPO in gills and digestive glands at concentrations below those from the initial fraction of dissolved Ag. The effects of nAg on MT levels in mussels were not discernible from those of dissolved Ag, but the 80-nm was 25-fold more potent than 20-nm nAg in inducing MT. Multivariate analysis revealed that the global responses of the 20- and 80-nm nAg were generally similar to those of dissolved Ag. Data also demonstrated that nAg are bioavailable for mussels where the immune system is a target during early exposure to nanoparticles.

Fate and Immunotoxic Effects of Silver Nanoparticles on Rainbow Trout in Natural Waters

“…In our case, the effects of Ag + and monomeric AgNPs were not discernable. This was also observed in a previous study where the effects of ionic Ag and AgNPs were not observable at the immunity level [27]. Our results showed that AgNO 3 induces immunostimulation in green and brown waters, whereas animmunosuppression in tap water is observed.…”

“…AgNPs were recognized to directly impact the immune system [25] and the toxicity cannot be entirely explained by Ag + ions release [26]. To prevent the oxidative stress caused by Ag + , defences mechanism were engaged like anti-oxidant proteins such as cysteine rich proteins like glutathione and thiols [27]. Moreover the oxidative damages could be followed by the determination of lipid peroxidation and the cyclooxygenase measures.…”

Immunomodulatory properties of silver nanoparticles contribute to anticancer strategy for murine fibrosarcoma

“…In fresh water fishes, AgNPs are known to be associated with an inflammatory response. 12 AgNPs have also been shown to inhibit molecules related to the cholinergic system and consequently impair the immune system differentiation in zebrafish. 13 AgNPs behave as allergens in mice, as reported in a recent proteome-based study.…”

Mechanisms of Nanotoxicity

“…Lysosomal membrane stability in the hemocytes was found to be impaired by nanocarbon black, fullerenes, silica, and titanium dioxide (Canesi et al, 2010b). Hemocyte number capable of ingesting fluorescent beads and hemocyte viability were significantly decreased on exposure to cadmium-telluride quantum dots (Gagné et al, 2008) and silver nanoparticles (Gagné et al, 2013).…”