Evidence of Endocrine Disruption and Oxidative Stress in Mytilus galloprovincialis Exposed to 17α-Ethinylestradiol

The presence of endocrine-disrupting compounds (EDCs) in aquatic environments has raised significant concerns, particularly regarding their impact on marine biota. Among these compounds, 17α-ethinylestradiol (EE2), a synthetic estrogen widely used in oral contraceptives, is highly persistent and biologically active at very low concentrations. This study evaluated the effects of EE2 exposure on oxidative stress responses and endocrine disruption in Mytilus galloprovincialis, exposed for 28 days to three EE2 concentrations (10, 30, and 300 ng·L−1). Biomarkers of oxidative stress, including the enzymatic activities of superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST), as well as Lipid Peroxidation (MDA levels), total ubiquitin (UBI) and the endocrine disruption marker, vitellogenin-like protein (VTG) were assessed. Results showed significant increase in GST and a decrease in CAT activities followed by an elevation at 300 ng·L−1, slightly higher than control values. Overall, results suggest an enhanced oxidative challenge. No significant changes were detected in MDA and UBI levels. VTG-like protein levels increased according to the EE2 concentrations tested, suggesting an effect on the mussel’s endocrine system. These results show the activation of detoxification and antioxidant defense mechanisms in exposed mussels as a response to mitigate oxidative stress damage. Furthermore, it highlights the importance of using biomarkers in pollution monitoring studies and environmental risk assessment.