Melatonin Loading Chitosan-Tripolyphosphate Nanoparticles: Application in Attenuating Etoposide-Induced Genotoxicity in HepG2 Cells

Etoposide is one of the most effective chemotherapeutic agents used in the treatment of various types of cancers. However, as a Topoisomerase II inhibitor, during clinical use, several side effects may occur. In addition, in several in vivo and in vitro studies, etoposide has been shown to have a range of genotoxic effects including single and double strand breaks. Melatonin is an anti-aging and antioxidant hormone synthesized from the pineal gland. The genoprotective, antioxidant, and free radical scavenger properties of melatonin have been well explained in various studies. The aim of this study was to explore whether melatonin nanoparticles protects against etoposide-induced genotoxicity in the HepG2 cell line. HepG2 cells (25 × 10⁴ cells/well) were cultured in 24-well plates: a control group and 3 melatonin and its nanoparticles + etoposide groups (pre- and cotreatment conditions). Our results show that etoposide induced a noticeable genotoxic effect in HepG2 cells. Melatonin reduced the effects of etoposide significantly in both types of experiment conditions, through the reduction of the level of DNA damage measured via comet assay. Furthermore, melatonin decreased the intracellular reactive oxygen species generation. It also increased the intracellular glutathione levels in HepG2 cells. Nano melatonin is more effective than regular melatonin. The most protective effect was observed with melatonin when it was administrated 24 h before etoposide treatment.