Toxicological evaluation of nano-sized colloidal silver in experiments on mice. Behavioral reactions, morphology of internals

The results of toxicity studies of nano-sized colloidal silver (NCC), the most widely used in medicine, food and life, are given. When evaluating safe doses of silver NP (using commercially available NCC solution stabilized with polyvinylpyrrolidone (PVP), with the size of silver NP at the range of 5-80 nm) when orally administered to male mice, BALB/c mice at doses of 0.1; 1.0 and 10 mg/kg of body weight per silver different effects from the motor and orienting-exploratory activity were revealed, for the part of them the dependence on the dose of the NCC was typical. The following peculiarities were found: reduction in motor activity to reduce the frequency of activities requiring physical effort, reduction of the execution time of these actions; increasing anxiety in terms of frequency and duration of attacks of orienting-investigative activity and animals washing. Morphological examination revealed a series of tissue changes of internal organs (especially liver and spleen, to a lesser extent - kidney, heart and colon) with increase of the spectrum and severity of structural changes with increasing doses of the NCC. From the combination of the data the conclusion was made that maximal ineffective dose (NOAEL) of this nanomaterial at subacute oral administration is no more than 0.1 mg/kg body weight.