Gadoteric Acid Induces Dose-Dependent DNA Damage and Enzyme Binding in Fibroblast Cells

Gadolinium-based contrast agents, widely used in magnetic resonance imaging, raise safety concerns due to their potential cytotoxic and genotoxic effects, especially at high doses or repeated exposures. In this study, the cytogenotoxic potential of gadoteric acid in NIH3T3 fibroblast cells was evaluated using in vitro and in silico approaches. NIH3T3 cells were treated with increasing concentrations of gadoteric acid. Cytotoxicity was evaluated by MTS assay and genotoxicity by comet assay; hydrogen peroxide (75 μM) was used as a positive control. In addition, the interaction of gadoteric acid with DNA topoisomerase IIα, DNA topoisomerase IIβ, DNA polymerase β, and B-DNA was examined by molecular docking. MTS assay results showed a dose-dependent decrease in cell viability with an IC₅₀ of 28.19 mM. Comet assay revealed significant DNA damage only at the highest concentration (56.38 mM) (p < 0.05), which also caused marked cytotoxicity. Thus, the observed DNA damage likely resulted from cytotoxicity stress rather than direct strand breaks. In silico docking predicted a high binding affinity of gadoteric acid for DNA polymerase β (-11.7 kcal/mol) and other DNA-related targets. However, these predictions require experimental validation. Overall, gadoteric acid exhibited dose-dependent cytotoxicity and limited genotoxicity at high concentrations, suggesting that DNA damage occurs secondary to cytotoxic effects rather than a direct genotoxic mechanism.