Prostanoids as Markers of Oxidative Stress in Stallion Semen

Prostanoids as Markers of Oxidative Stress in Stallion SemenStandard pre-processing semen assessment does not reliably predict quality after chilled storage. Oxidative stress in stallion semen during cooling damages sperm membranes via lipid peroxidation, reducing fertilizing potential. This study investigated whether seminal plasma prostanoids — established lipid peroxidation biomarkers — could predict chilled semen quality in stallions.

Study Design:

  • Semen collected from 9 stallions via artificial vagina; extended to 25–35 million sperm/ml
  • Stallions classified as good chillers (progressive motility >30% at 24h; n=5) or poor chillers (progressive motility <30% at 24h; n=4)
  • Sperm assessed at 0, 24, 48, 72, and 96 hours for total motility, progressive motility, viability, DNA integrity, and morphology
  • Seminal plasma prostanoid profiles identified via chromatography tandem mass spectrometry (n=13)

Key Results:

  • Total motility, progressive motility, and viability declined significantly from 0 to 24–48 hours across all stallions
  • Good and poor chillers were indistinguishable at time 0; significant differences emerged at 24 and 48 hours (p<0.001)
  • Four prostanoids correlated with functional sperm parameters:
    • 8-F3t-IsoP: negatively correlated with progressive motility
    • 8-iso PGF2α: positively correlated with DNA integrity
    • 20-F4t-NeuroP: positively correlated with viability
    • 5-F2t-IsoP: significantly elevated in poor chillers at 24 hours (p=0.039); strongly negatively correlated with chilling ability (R=–0.772)

Conclusions:

  • Seminal plasma prostanoids show promise as predictive biomarkers of chilled semen quality that standard assessment cannot detect
  • 5-F2t-IsoP is identified as a particularly strong oxidative stress marker differentiating good from poor chillers
  • Findings lay groundwork for development of targeted oxidative stress biosensors for equine semen evaluation

(Gallacher K, Noschka E, Mihm Carmichael M, Rozek T, Galano JM, Durand T, Oger C, Barnes SA. 2025. Prostanoids as markers of oxidative stress in stallion semen. Journal of Equine Veterinary Science 145:105287. https://doi.org/10.1016/j.jevs.2024.105287 – Presented in Association with and by Permission of the International Society for Equine Reproduction)