Toxicological analysis of triadimefon on endocrine disruption and oxidative stress during rare minnow (Gobiocypris rarus) larvae development.

Triadimefon (TDF) is a systemic wide-spectrum antifungal compound that is widely used in agriculture to inhibit fungal growth on various crops. Since previous studies focused on the embryo and adult life stages in the investigation of ecological impact, here we investigated the long-term effects of TDF (1, 10, 100 μg/L) on rare minnow during its larvae development. TDF caused an anti-estrogenic effect by decreasing vitellogenin (VTG) and CYP19a mRNA level, and inhibiting the aromatase activity and VTG levels after a 3, 6, 10, or 14-day exposure in rare minnow larvae. TDF also disturbed the endocrine disruption by regulating the transcription of estrogen receptors ERα, ERβ1 and ERβ2, CYP1a, CYP11, CYP17, steroidogenic acute regulator (STAR), doublesex and mab-3 related transcription factor (DMRT1), gonadotropin-releasing hormone (GnRH2), GnRH3, GnRHR1A, and GnRHR1B. Furthermore, TDF induced the accumulation of reactive oxygen species (ROS) and the activity of antioxidant proteins glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT), and significantly increased the transcriptions of stress response genes P53, growth arrest and DNA damage-inducible 45 alpha (Gadd45α), and COX1, suggested that TDF might cause oxidative stress during larvae development. The changes in transcript and biological levels represented the potential adaptive or compensatory responses to impaired oxidative stress and endocrine system after TDF exposure in rare minnow during its larvae development.