Investigation of silver (Ag) deposition in tissues from stranded cetaceans by autometallography (AMG)

Immunotoxicity of Silver Nanoparticles (AgNPs) on the Leukocytes of Common Bottlenose Dolphins (Tursiops truncatus)

“…5E ). A marked increase in the number of apoptotic cells was noted in cPMNs without C-AgNP 20 after 16 h incubation, which might be similar to the spontaneous apoptosis found in human neutrophils 29 , 35 .

Figure 5 Cytotoxicity of C-AgNP 20 in cPMNs and cPBMCs.

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“…The biodistribution of AgNPs or Ag in cetaceans is still largely unknown, but previous in vivo studies of AgNPs and Ag by oral exposure in laboratory rats demonstrated that the silver concentration is approximately 10 times higher in the liver than in blood or plasma 16 , 21 , 23 . Based on the concept of these laboratory animal models, it is presumed that the Ag concentration in the blood of stranded cetaceans may range from 0.01 to 72.6 μg/ml 34 , 35 . Although the state of Ag and AgNPs in the body of cetaceans is undetermined, complicated, and various, the current results still suggest that the immune function of cetaceans may have been compromised by AgNPs and/or Ag, and the immunotoxic effects of AgNPs in marine mammals should not be overlooked.…”

Th2 cytokine bias induced by silver nanoparticles in peripheral blood mononuclear cells of common bottlenose dolphins (Tursiops truncatus)

“…A variety of infections caused by intracellular pathogens in cetaceans have been reported and may be associated with the mass stranding events of cetaceans ( Cvetnic et al, 2016 ; Domingo et al, 1990 ; Domingo et al, 1992 ; Dubey et al, 2007 ; Dubey et al, 2008 ; Mazzariol et al, 2016 ; Mazzariol et al, 2017 ). In addition, previous studies suggested that Ag contamination exists in all aspects of the marine ecosystem, and cetaceans may have been negatively affected by Ag contamination ( Becker et al, 1995 ; Caceres-Saez et al, 2013 ; Chen et al, 2017 ; Dehn et al, 2006 ; Kunito et al, 2004 ; Li et al, 2018a ; Mendez-Fernandez et al., 2014 ; Reed et al, 2015 ; Rosa et al, 2008 ; Seixas et al, 2009 ; Woshner et al, 2001 ). The direct correlation between the infection of intracellular pathogens and the severity of Ag contamination in cetaceans is worth studying.…”

“…Furthermore, although the biodistribution of AgNPs or Ag in cetaceans is still undetermined, previous in vivo studies of AgNPs by oral exposure in laboratory rats demonstrated that the Ag concentration in the liver is approximately 10 times higher than that in the blood or plasma ( Lee et al, 2013 ; Loeschner et al, 2011 ; Van der Zande et al, 2012 ). Based on these animal models, it is presumed that the Ag concentrations in the blood of cetaceans may range from 0.01 to 72.6 µg/ml ( Chen et al, 2017 ; Li et al, 2018a ). Although previous studies have indicated that the status of AgNPs in the aquatic environment is complicated and variable (i.e., the concentrations of AgNPs and other Ag/Ag compounds are still undetermined in cetaceans)( Levard et al, 2012 ; Massarsky, Trudeau & Moon, 2014 ), our data suggest that cetaceans may be negatively affected by AgNPs.…”

“…AgNPs can be released during the production, transport, decay, use, and/or disposal of AgNP-containing products, subsequently draining into the surface water and then accumulating in the marine environment ( Farre et al, 2009 ; Walters, Pool & Somerset, 2014 ). Therefore, the increasing use and growing production of AgNPs, as potential sources of Ag contamination, raise public concerns about the environmental toxicity of Ag ( Li et al, 2018a ). Previous research has demonstrated that AgNPs can precipitate in marine sediments, be ingested by benthic organisms (such as benthic invertebrate species), enter and be transferred from one trophic level to the next via the food chain, and thereby cause negative effects on the animals at different trophic levels, such as algae, invertebrates and fishes ( Buffet et al, 2014 ; Farre et al, 2009 ; Gambardella et al, 2015 ; Huang, Cheng & Yi, 2016b ; Wang et al, 2014 ).…”