In vivo zearalenone exposure dose-dependently compromises mouse oocyte competence by impairing chromatin configuration and gene transcription.

Although in vivo and in vitro zearalenone (ZEN) exposure impaired oocyte quality, the mechanisms by which ZEN damages oocytes and the lowest observed effect level remain unclear. Furthermore, although it is known that premature chromatin condensation may occur in oocytes under proapoptotic conditions, whether ZEN exposure compromises oocyte competence by impairing gene transcription by causing premature chromatin condensation remains to be investigated. This study tested the toxic concentrations of in vivo ZEN exposure that impair oocyte preimplantation developmental potential (PIDP) and the hypothesis that ZEN exposure compromises oocyte competence by increasing oxidative stress and changing chromatin configuration and the transcription of related genes. We found that in vivo treatment of mice (Kunming strain, 8 weeks after birth) with 0.5–1 mg kg⁻¹ ZEN daily for 5 days, impaired the PIDP of mouse oocytes, increased oxidative stress, disturbed spindle assembly and chromosome segregation, caused premature chromatin condensation, impaired global gene transcription and disturbed the expression of genes related to oocyte competence, spindle assembly, redox potential and apoptosis. In conclusion, ZEN dose-dependently compromised the competence of mouse oocytes by causing oxidative stress and impairing chromatin configuration and gene transcription. Because zearalenone (ZEN) can enter the food chain and cause health problems, studies of its toxic effects on oocytes are of great importance for healthy reproduction in both humans and animals. This study demonstrates that ZEN dose-dependently compromises the competence of mouse oocytes by causing oxidative stress and impairing chromatin configuration and gene transcription. These data will contribute to our understanding of the mechanisms by which ZEN and other similar toxins impair oocyte quality, and thus female reproduction. [ABSTRACT FROM AUTHOR]