engleski

Evaluation of Oxidative Stress Response and Primary DNA Damage in HepG2 Cell Line Exposed to Ketamine

Introduction: Ketamine is a dissociative anaesthetic widely used in clinical practice, while its subanaesthetic administration has been explored for treatment of depression and chronic pain. Due to its hallucinogenic and dissociative effects, ketamine is also used as a recreational drug. Agents used for the induction of anaesthesia have been shown to promote oxidative stress, which has been implicated in the aetiology of various chronic diseases. Research of oxidative/antioxidative properties of ketamine has so far produced ambiguous findings, while data on genotoxicity are insufficient to reach a conclusion on its genotoxic potential. Methods: In order to investigate the unexplored effects of ketamine on cell level, hepatocytes HepG2 were exposed to ketamine at concentrations of 0.09, 0.37 and 1.49 mg/L for 24 h, relevant in case of analgesia, anesthesia or drug-abuse. Cell viability was studied using the MTS assay. Ketamine toxicity was further evaluated using markers of DNA damage and oxidative stress according to a specific method protocol. Lipid peroxidation level [malondialdehyde (MDA)], reactive oxygen species (ROS) production and glutathione (GSH) levels were measured as biomarkers of oxidative stress, while primary DNA damage was determined using the alkaline comet assay. Results: The selected concentrations of ketamine did not decrease cell viability below 90 %. Although no changes in ROS levels were visible after the treatment, a significant decrease in concentration of MDA and GSH was observed at all three ketamine concentrations in comparison to control cells. Ketamine treatment at all of the tested concentrations resulted in a significant increase of primary DNA damage versus the negative control. We also found significant concentration- dependent differences in DNA damage after exposure to ketamine. The observed DNA damage pattern could be associated with specific interactions of ketamine and/or its metabolites with DNA (most likely intercalations), as well as with a repair- induced onset of additional breaks, which affected the amounts of lesions detectable by alkaline comet assay. Conclusion: The findings regarding genotoxic potency of ketamine detected in vitro, together with the observed imbalance in the oxidative- antioxidant equilibrium detected in HepG2 cells call for additional studies on a wider range of doses and other experimental models. Future studies at DNA level should focus on the use of specific modifications of the comet assay and related methods that will prove the presumed mechanisms of interaction of the tested substance with the DNA molecule. Funding: This research was supported by the programme of cooperation between the Institute for Medical Research and Occupational Health (Zagreb, Croatia) and the University North (Varaždin, Croatia) and the Croatian Science Foundation’s grant number HrZZ- UIP-2017-05-7260.

ketamine ; genotoxicity ; primary DNA damage ; oxidative stress

nije evidentirano