In vitro acute exposure to DEHP affects oocyte meiotic maturation, energy and oxidative stress parameters in a large animal model.
Authors: Ambruosi Barbara, Uranio Manuel Filioli, Sardanelli Anna Maria, Pocar Paola, Martino Nicola Antonio, Paternoster Maria Stefania, Amati Francesca, Dell'Aquila Maria Elena
Journal: PloS one
Summary
# Editorial Summary: DEHP Exposure and Equine Oocyte Maturation Di-(2-ethylhexyl) phthalate (DEHP), a chemical widely used in plastics and consumer products, acts as an endocrine disruptor and poses potential fertility risks across species; this research examined its effects on equine reproduction using cumulus-oocyte complexes harvested from slaughterhouse mares and cultured in vitro with three DEHP concentrations (0.12, 12, and 1200 µM). The findings revealed a biphasic response: low-dose exposure (0.12 µM) significantly impaired oocyte maturation to metaphase II stage through increased cumulus cell apoptosis and paradoxically reduced reactive oxygen species (ROS) levels, whilst higher concentrations (12 and 1200 µM) triggered cumulus cell damage and excessive ROS without blocking maturation itself. Oocytes that successfully matured despite DEHP exposure maintained normal mitochondrial function, antioxidant enzyme activity and oxidative balance, though they showed elevated ATP content potentially from glycolytic rather than mitochondrial sources. For equine practitioners, these findings suggest that acute DEHP contamination during oocyte development could compromise fertility by disrupting the cumulus-oocyte dialogue necessary for meiotic progression, yet matured oocytes retain developmental competence—implying that timing and concentration of exposure may be critical determinants of reproductive outcomes in mares.
Read the full abstract on PubMed
Practical Takeaways
- •Environmental phthalate exposure (common in plastics and consumer products) may impair mare fertility at surprisingly low concentrations; consider reproductive management strategies for mares with high environmental exposure.
- •The dose-dependent biphasic response suggests that oocyte maturation failure and cumulus cell dysfunction occur through different mechanisms, which may inform future therapeutic interventions for fertility issues.
- •Mares with DEHP-exposed oocytes that do achieve maturation retain developmental competence, but further in vivo studies are needed before drawing conclusions about breeding outcomes.
Key Findings
- •Low-dose DEHP (0.12 µM) significantly inhibited oocyte maturation in equine oocytes through increased cumulus cell apoptosis and reduced ROS levels (P<0.05).
- •High-dose DEHP (12-1200 µM) induced cumulus cell apoptosis and ROS increase without affecting oocyte nuclear maturation (P<0.0001).
- •Matured oocytes exposed to DEHP showed increased ATP content despite normal mitochondrial distribution and energy status, suggesting altered glycolytic metabolism.
- •N-Acetyl-Cysteine co-treatment reversed DEHP-induced apoptosis and ROS elevation in cumulus cells but did not restore oocyte maturation rates.