In vitro evaluation of co-exposure of arsenium and an organic nanomaterial (fullerene, C60) in zebrafish hepatocytes

Taking into account the concept of the “Trojan Horse”, where contaminants may have its entry into specific organs potentiated by its association with nanomaterials, the aim of this study was to analyze the joint toxic effects induced by an organic nanomaterial, fullerene (C60) with the metalloid arsenic (AsIII). Hepatocytes of zebrafish Danio rerio were exposed to AsIII (2.5 or 100 μM), C60 or As + C60 for 4 h, not altering cells viability. Intracellular reactive oxygen species concentration was reduced in cells exposed only to the C60 (1 mg/L) and in the treatment of 100 μM AsIII + C60. Co-exposure with C60 abolished the peak of the antioxidant glutathione (GSH) registered in cells exposed to the lowest AsIII concentration (2.5 μM). A similar result was observed in terms of lipid damage (TBARS). Total antioxidant capacity was significantly higher at both AsIII concentrations co-exposed to C60 when compared with the control group. Activity of glutathione-S-transferase omega, a limiting enzyme in the methylation pathway of AsIII, was reduced in the 100 μM AsIII + C60 treatment. Cells co-exposed to C60 had a significantly higher accumulation of AsIII, showing a “Trojan Horse” effect which did not result in higher cell toxicity. Instead, co-exposure of AsIII with C60 showed to reduce cellular injury.