Genotoxicity of ferric oxide nanoparticles in Raphanus sativus: Deciphering the role of signaling factors, oxidative stress and cell death.

We have studied the genotoxic and apoptotic potential of ferric oxide nanoparticles (Fe 2 O 3 -NPs) in Raphanus sativus (radish). Fe 2 O 3 -NPs retarded the root length and seed germination in radish. Ultrathin sections of treated roots showed subcellular localization of Fe 2 O 3 -NPs, along with the appearance of damaged mitochondria and excessive vacuolization. Flow cytometric analysis of Fe 2 O 3 -NPs (1.0 mg/mL) treated groups exhibited 219.5%, 161%, 120.4% and 161.4% increase in intracellular reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨm), nitric oxide (NO) and Ca 2+ influx in radish protoplasts. A concentration dependent increase in the antioxidative enzymes glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and lipid peroxidation (LPO) has been recorded. Comet assay showed a concentration dependent increase in deoxyribonucleic acid (DNA) strand breaks in Fe 2 O 3 -NPs treated groups. Cell cycle analysis revealed 88.4% of cells in sub-G1 apoptotic phase, suggesting cell death in Fe 2 O 3 -NPs (2.0 mg/mL) treated group. Taking together, the genotoxicity induced by Fe 2 O 3 -NPs highlights the importance of environmental risk associated with improper disposal of nanoparticles (NPs) and radish can serve as a good indicator for measuring the phytotoxicity of NPs grown in NP-polluted environment. [ABSTRACT FROM AUTHOR]