SUMMARY
Background: Arsenic, an environmental pollutant, is a carcinogenic metalloid and also an anticancer agent.Objective: To evaluate the toxicity of arsenic nanoparticles in rat hepatocytes. Methods: Freshly isolated rat hepatocytes were exposed to 0, 20, 40, and 100 µM of arsenic nanoparticles and its bulk counterpart. Their viability, reactive oxygen species level, glutathione depletion, mitochondrial and lysosomal damage, and apoptosis were evaluated.Results: By all concentrations, lysosomal damage and apoptosis were clearly evident in hepatocytes exposed to arsenic nanoparticles. Evaluation of mitochondria and lysosomes revealed that lysosomes were highly damaged.Conclusion: Exposure to arsenic nanoparticles causes apoptosis and organelle impairment. The nanoparticles have potentially higher toxicity than the bulk arsenic. Lysosomes are highly affected. It seems that, instead of mitochondria, lysosomes are the first target organelles involved in the toxicity induced by arsenic nanoparticles.