Toxicological effects of silver nanoparticles and cadmium chloride in macrophage cell line (RAW 264.7): An in vitro approach.

BACKGROUND: Silver nanoparticles (AgNP) are largely used in nanotechnological products, but the real risks for human and environment are still poorly understood if we consider the effects of mixtures of AgNP and environmental contaminants, such as non-essential metals. METHODS: The aim of the present study was to investigate the cytotoxicity and toxicological interaction of AgNP (1-4 nm, 0.36 and 3.6 µg mL-1) and cadmium (Cd, 1 and 10 µM) mixtures. The murine macrophage cell line RAW 264.7 was used as a model. RESULTS: Effects were observed after a few hours (4 h) on reactive oxygen species (ROS) and became more pronounced after 24 h-exposure. Cell death occurred by apoptosis, and loss of cell viability (24 h-exposure) was preceded by increases of ROS levels and DNA repair foci, but not of NO levels. Co-exposure potentiated some effects (decrease of cell viability and increase of ROS and NO levels), indicating toxicological interaction. CONCLUSION: These effects are important findings that must be better investigated, since the interaction of Cd with AgNP from nanoproducts may impair the function of macrophages and represent a health risk for humans.

Tribromophenol affects the metabolism, proliferation, migration and multidrug resistance transporters activity of murine melanoma cells B16F1.

Murine melanoma cells B16F1 were exposed to the flame retardant and wood preservative chemical 2,4,6-tribromophenol (TBP) during 24 and 48 h, at the concentrations found in human diet. TBP-exposed cells had increased MTT and Alamar blue® metabolism and ABCB5 mRNA levels (qPCR), but the cells had decreased proliferation (crystal violet assay), migration (scratch assay), and drug-effux transporters activity (rhodamine B efflux assay). Exposure to TBP did not affect the cell viability (neutral red and annexin V-PI assays), colony formation (colony number, clonogenic assay), and the levels of reactive oxygen species (DCF probe) or P53 mRNA (qPCR). The tested TBP concentrations had low toxicity to melanoma cells B16F1. However, dual effect on metastatic profile and chemoresistance suggests that the increase of ABCB5 positively modulates the cell chemoresistance, but decreases cell migration and proliferation. These findings may be explored in cancer therapy.