Influence of orally introduced silver nanoparticles on content of essential and toxic trace elements in organism

Nanoscale colloidal silver (NCS) is one of the most popular products of nanotechnology and is widely used in cosmetics, food supplements, and other types of consumer products. The aim of this work is to study the influence of NCSs orally introduced into rats during an experiment lasting 92 days on some indicators of homeostasis of essential and toxic trace elements. The Argovit-C NCSs produced by Vector Vita LTD, Novosibirsk, Russia with silver (Ag) nanoparticles of the diameter in the range of 5-80 nm according to transmission electron microscopy and dynamic laser light scattering. The drug is introduced into growing male Wistar rats in doses ranging from 0.1 to 10 mg/kg body weight (b.w.) for 1 month by gavage and then with a diet consumed for 62 days. The control animals receive deionized water or an aqueous solution of the stabilizer polyvinylpyrrolidone. The content of Ag, cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) in the liver, kidneys, and spleen is determined by mass spectrometry with inductively coupled plasma; selenium (Se) in serum and urine is measured by spectrofluorimetric method and glutathione peroxidase activity by the enzymatic spectrophotometric method. The dose-dependent accumulation of Ag in the animal liver at a dosage ranging 0.1–10 mg/kg b.w. and kidney and spleen in the range of 0.1–1 mg/kg b.w. is revealed. A significant decrease in the content of Cu in the kidneys; a decrease in Zn and Co content and increase in Mn content in the liver; and an increase in Cd, Cr, and Ni in spleen of animals receiving NCS at various doses are found. A significant positive correlation is found between the levels of Ag and Cd, Ni, Cr in the spleen, and a negative one is found between Ag and Cu in the kidneys. Indicators of Se provision (urinary excretion, the content in the blood plasma, the activity of glutathione peroxidase) are significantly lower in rats receiving NCS at a dose of 1.0–10 mg/kg b.w. Thus, NCSs, entering the body through the gastrointestinal tract at a dose of silver of at least 1 mg/kg b.w. may affect the homeostasis of essential and toxic trace elements. The antagonism of Ag (as part of the NCS) and Se in the composition of the diet should be taken into account in assessing the safety of widely used food supplements–sources of colloidal Ag.