Cytotoxic effects of silver nanoparticles and non-essential metals in murine macrophages

Silver nanoparticles (AgNPs) are widely used in nanotechnology products. However, the health risks associated with co-exposure to these emerging contaminants and environmental pollutants, such as non-essential metals, are poorly understood. The present study aimed to investigate the cytotoxicity and toxicological interaction of AgNPs (0.36 and 3.6 μg mL^-1) + lead (Pb²⁺, 25 and 250 μM) and AgNPs + mercury (Hg²⁺, 15 and 150 μM) using the macrophage cell line RAW 264.7 as a model. Effects were observed after a few hours (4 h) on NO levels, phagocytic activity, and DNA damage. Cell viability (24 h-exposure) was affected mainly by the higher concentrations of the contaminants and their mixtures, preceded by increases in NO levels and DNA damage, but without effects on ROS levels. Co-exposure potentiated some effects (ROS and NO levels and DNA damage), indicating toxicological interaction. These important findings must be further investigated, since the interaction of Pb²⁺ and Hg²⁺ with AgNPs from nanoproducts may impair the function of macrophages and represent a health risk for humans.