Investigation on cobalt-oxide nanoparticles cyto-genotoxicity and inflammatory response in two types of respiratory cells

The increasing use of cobalt oxide (Co3O4) nanoparticles (NPs) in several applications and the suggested genotoxic potential of Co-oxide highlight the importance of evaluating Co3O4 NPs toxicity. Cyto-genotoxic and inflammatory effects induced by Co3O4 NPs were investigated in human alveolar (A549), and bronchial (BEAS-2B) cells exposed to 1-40 mu g ml(-1). The physicochemical properties of tested NPs were analysed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Cytotoxicity was studied to analyze cell viability (WST1 test) and membrane damage (LDH assay), direct/oxidative DNA damage was assessed by the Formamido-pyrimidine glycosylase (Fpg)-modified comet assay and inflammation by interleukin (IL)-6, IL-8 and tumor necrosis factor-alpha (TNF-) release (ELISA). In A549 cells, no cytotoxicity was found, whereas BEAS-2B cells showed a viability reduction at 40 mu g ml(-1) and early membrane damage at 1, 5 and 40 mu g ml-1. In A549 cells, direct and oxidative DNA damage at 20 and 40 mu g ml(-1) were detected without any effects on cytokine release. In BEAS-2B cells, significant direct DNA damage at 40 mu g ml(-1) and significant oxidative DNA damage with a peak at 5 mu g ml(-1), that was associated with increased TNF- release at 1 mu g ml(-1) after 2 h and increased IL-8 release at 20 mu g ml(-1) after 24 h, were detected. The findings show in the transformed alveolar cells no cytotoxicity and genotoxic/oxidative effects at 20 and 40 mu g ml(-1). In normal bronchial cells, moderate cytotoxicity, direct DNA damage only at the highest concentration and significant oxidative-inflammatory effects at lower concentrations were detected. The findings confirm the genotoxic-oxidative potential of Co3O4 NPs and show greater sensitivity of BEAS-2B cells to cytotoxic and oxidative-inflammatory effects suggesting the use of different cell lines and multiple end-points to elucidate Co3O4 NPs toxicity. Copyright (c) 2015 John Wiley & Sons, Ltd.