Evaluation of distribution, redox parameters, and genotoxicity in Wistar rats co-exposed to silver and titanium dioxide nanoparticles.

The increasing production of silver nanoparticles (AgNPs) and titanium dioxide nanoparticles (TiONPs) has resulted in their elevated concentrations in the environment. This study was, therefore, aimed at determining the distribution, redox parameters, and genotoxic effects in male Wistar rats that were treated with either AgNP or TiONP individually, as well as under a co-exposure scenario. Animals were exposed via oral gavage to either sodium citrate buffer (vehicle), 0.5 mg/kg/day TiONP, 0.5 mg/kg/day AgNP or a mixture of TiONPs and AgNPs. Exposure lasted 45 days after which rats were sacrificed, and tissue biodistribution of Ag and Ti measured. The blood concentration of glutathione (GSH) and activities of glutathione peroxidase (GPx) and catalase (CAT) were determined while the genotoxicity was analyzed using the comet assay in peripheral blood and liver cells. The tissue concentrations of Ag followed the order; blood > liver > kidneys while for Ti the order was kidneys > liver > blood. There was no significant change in the measured redox parameters in animals that were exposed to TiONPs. However, there was a significant increase in GSH levels accompanied by a reduction in the GPx activity in AgNP-treated and co-exposed groups. The individual or co-exposure to TiONP and AgNP did not markedly induce genotoxicity in blood or liver cells. Data showed that TiONP did not produce significant oxidative stress or genotoxicity in rats at the dose used in this study while the same dose level of AgNPs resulted in oxidative stress, but no noticeable adverse genotoxic effects.