Comparative in Vivo Assessment of Some Adverse Bioeffects of Equidimensional Gold and Silver Nanoparticles and the Attenuation of Nanosilver’s Effects with a Complex of Innocuous Bioprotectors

Abstract

Stable suspensions of nanogold (NG) and nanosilver (NS) with mean particle diameter 50 and 49 nm, respectively, were prepared by laser ablation of metals in water. To assess rat’s pulmonary phagocytosis response to a single intratracheal instillation of these suspensions, we used optical, transmission electron, and semi-contact atomic force microscopy. NG and NS were also repeatedly injected intraperitoneally into rats at a dose of 10 mg/kg (0.5 mg per mL of deionized water) three times a week, up to 20 injections. A group of rats was thus injected with NS after oral administration of a “bioprotective complex” (BPC) comprised of pectin, multivitamins, some amino acids, calcium, selenium, and omega-3 PUFA. After the termination of the injections, many functional and biochemical indices and histopathological features of the spleen, kidneys and liver were evaluated for signs of toxicity, and accumulation of NG or NS in these organs was measured. From the same rats, we obtained cell suspensions of different tissues for performing the RAPD test. It was demonstrated that, although both nanometals were adversely bioactive in all respects considered in this study, NS was more noxious as compared with NG, and that the BPC tested by us attenuated both the toxicity and genotoxicity of NS.

Looking for Biological Protectors against Adverse Health Effects of Some Nanoparticles that Can Pollute Workplace and Ambient Air (A Summary of Authors’ Experimental Results)

“…Indeed, in both of these organs we observed an explicit pathology the type of which virtually did not depend on the chemical nature of the Me-NPs, and this pathology was also alleviated by background BPCs administration as exemplified in Table 2 by the results of an experiment with Ag-NPs [78].…”

“…In the experiment with a combined exposure to NiO-NPs plus Mn 3 O 4 -NPs [83], BPC administration significantly decreased the retention of nickel, though not of manganese, in the liver, spleen and brain. Under exposure to Ag-NPs, the retention of silver in the liver, spleen and kidneys over the control levels was very significant but did not depend at all on BPC administration [78]. We believe that this seeming inconsistency is due to the predominance of toxicodynamic bio-protection mechanisms over toxicokinetic ones.…”

“…In our experiments, bio-protectors employing mechanisms that are not fully identical proved to be most effective when administered in combinations which we call "bio-protective complexes", or BPCs [78] [80] [90].…”

“…We therefore decided to try and make the same goal attainable going from the other end, namely to enhance the natural resistance to the adverse health effects of Me-NPs [86]. This idea of possibly efficient "biological protection" against nano-toxicity was based on our long-term experience of successful bio-protection of the animal and human organism against various other toxicants, including some mineral microparticles [78] [80] [90].…”

“…As concerns bio-protection against the adverse effects of metallic nanoparticles, we have so far chosen, based on the above formulated theoretical premises, and experimentally tested four BPCs protecting from nano-silver [78], nano-copper oxide [82], and combinations of NiO-NP + Mn 3 O 4 -NP [83] [84] [85] and PbO-NP + CuO-NP + ZnO-NP [91]. Being different in some important details depending on specific toxicodynamic and toxicokinetic mechanisms underlying the toxic action of different metals, the compositions of all those BPCs still has much in common.…”