title: Oxidative stress contributes to cobalt oxide nanoparticles-induced cytotoxicity and DNA damage in human hepatocarcinoma cells.
abstract: BACKGROUND
  Cobalt oxide nanoparticles (Co(3)O(4)NPs) are increasingly recognized for their utility in biological applications, magnetic resonance imaging, and drug delivery. However, little is known about the toxicity of Co(3)O(4)NPs in human cells.
  
  
  METHODS
  We investigated the possible mechanisms of genotoxicity induced by Co(3)O(4)NPs in human hepatocarcinoma (HepG2) cells. Cell viability, reactive oxygen species (ROS), glutathione, thiobarbituric acid reactive substance, apoptosis, and DNA damage were assessed in HepG2 cells after Co(3)O(4)NPs and Co(2+) exposure.
  
  
  RESULTS
  Co(3)O(4)NPs elicited a significant (P < 0.01) reduction in glutathione with a concomitant increase in lipid hydroperoxide, ROS generation, superoxide dismutase, and catalase activity after 24- and 48-hour exposure. Co(3)O(4)NPs had a mild cytotoxic effect in HepG2 cells; however, it induced ROS and oxidative stress, leading to DNA damage, a probable mechanism of genotoxicity. The comet assay showed a statistically significant (P < 0.01) dose- and time-related increase in DNA damage for Co(3)O(4)NPs, whereas Co(2+) induced less change than Co(3)O(4)NPs but significantly more than control.
  
  
  CONCLUSIONS
  Our results demonstrated that Co(3)O(4)NPs induced cytotoxicity and genotoxicity in HepG2 cells through ROS and oxidative stress.
authors: Cell and Molecular Laboratory, Department of Zoology, Faculty of Science, King Saud University, Riyadh, Saudi Arabia.
authors: Saud
authors: S
authors: Alarifi
authors: Daoud
authors: D
authors: Ali
authors: Al Omar Suliman
authors: AO
authors: Y
authors: Maqusood
authors: M
authors: Ahamed
authors: Maqsood A
authors: MA
authors: Siddiqui
authors: Abdulaziz A
authors: AA
authors: Al-Khedhairy
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D053148:Caspase 3 / Q000378:metabolism; D002417:Cattle; D003035:Cobalt / Q000494:pharmacology*; D004249:DNA Damage; D056945:Hep G2 Cells; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D053768:Metal Nanoparticles / Q000008:administration & dosage*; D018384:Oxidative Stress / Q000187:drug effects*; D010087:Oxides / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D010087:Oxides; D017382:Reactive Oxygen Species; D003035:Cobalt; D053148:Caspase 3; C060728:cobalt oxide
keywords: DNA damage; HepG2 cells; cobalt oxide nanoparticles; cytotoxicity; oxidative stress