Does over-exposure to copper ions released from metallic copper induce cytotoxic and genotoxic effects on mammalian cells?

Background: A high dissolution of copper from intrauterine devices (IUDs) occurs during the first days after insertion. This work is focused on the assessment of the possible cyto- and genotoxic effects of different concentrations of copper ions released from metallic copper on mammalian cells in vitro.

Study Design: Colorimetric tetrazolium/Trypan blue (TB) tests and Comet assay were used to evaluate potential cytotoxicity and genotoxicity, respectively, in Chinese hamster ovary cells (CHO-K1).

Results: Reduction of mitochondrial activity by copper ions was observed for extracts at >or=7.42 mg/L concentrations, while TB exclusion test for plasma membrane integrity showed significant decrease in cell viability (close to 90%) for 10.85 mg/L concentration. Additionally, copper-induced DNA damage was detected for 5.67-7.42 mg/L concentration range.

Conclusion: Our results demonstrate cytotoxic and genotoxic effects of copper ions released from metallic copper on CHO-K1 cells and emphasize the importance of reducing the initial copper dissolution from IUD without affecting the contraceptive action.