Abstract
Nanomaterials have been widely used in diverse areas. Heavy metals are ubiquitous environmental pollutants. In spite of the real risk of humans' co-exposure to nanoparticles and heavy metals, their combined toxicity has received little attention. We have reported that silica nanoparticles and CdCl(2) have a positive synergistic toxicity in mice. Here, we demonstrate that Fe(3)O(4) nanoparticles (nano-Fe(3)O(4)) and CdCl(2) have a negative synergistic toxicity in mice. Nano-Fe(3)O(4) showed low toxicity in mice. In contrast, CdCl(2) caused significant oxidative damage mainly in the liver as indicated by severe liver dysfunction and histopathological abnormalities. Co-exposure to nano-Fe(3)O(4) and CdCl(2) significantly attenuated CdCl(2)-induced damage in the liver through reduction of oxidative stress. Nano-Fe(3)O(4) and CdCl(2) had negative cooperative effects on the biodistributions of Fe and Cd in mice due to mutually competitive inhibition of Fe and Cd uptake. The reduction of Cd accumulation in tissues and the inhibition of Cd-induced deprivation of tissue Fe by nano-Fe(3)O(4) played two key roles in the protective effect of nano-Fe(3)O(4) on CdCl(2)-induced oxidative damage.