The Proteome of Equine Oviductal Fluid Varies Before and After Ovulation: A Comparative Study.
Authors: Fernández-Hernández Pablo, Marinaro Federica, Sánchez-Calabuig María Jesús, García-Marín Luis Jesús, Bragado María Julia, González-Fernández Lauro, Macías-García Beatriz
Journal: Frontiers in veterinary science
Summary
# Editorial Summary The equine oviduct creates a biochemical environment critical for fertilisation and early embryo development, yet the specific molecular signals governing this process remain poorly understood—particularly because horse sperm cannot penetrate the zona pellucida outside the reproductive tract. Researchers used mass spectrometry (LC-MS/MS) to compare the protein composition of oviductal fluid collected postmortem from mares with pre-ovulatory follicles versus those with recent ovulations (n=4 per group), identifying 1,173 total proteins including 691 unique to horses. The post-ovulatory fluid showed dramatically altered protein expression: 156 proteins were upregulated and 15 downregulated after ovulation, with notably 87 upregulated proteins involved in protein metabolism pathways—suggesting the oviduct substantially remodels its environment to support sperm function and early embryonic needs. These findings provide insight into which molecular factors may be essential for successful fertilisation in mares and could inform development of improved assisted reproductive techniques or identification of fertility markers in breeding programmes. Understanding this dynamic proteome shift may also have relevance for practitioners managing mares with reproductive difficulties or those monitoring fertility status during the breeding season.
Read the full abstract on PubMed
Practical Takeaways
- •Understanding oviductal fluid composition changes around ovulation may improve in vitro fertilization protocols and assisted reproduction techniques in horses
- •The identification of specific proteins upregulated post-ovulation provides targets for enhancing embryo development in breeding programs
- •This research supports the biological basis for timing of breeding and artificial insemination relative to ovulation
Key Findings
- •1,173 proteins were identified in equine oviductal fluid, with 691 unique to Equus caballus
- •156 proteins were upregulated in post-ovulatory oviductal fluid compared to pre-ovulatory fluid
- •87 of the upregulated proteins were involved in protein metabolism pathways
- •Significant proteomic differences exist between pre-ovulatory and post-ovulatory oviductal fluid that relate to sperm-oviduct interaction and fertilization