Proteomic Differences Between the Ovulatory and Anovulatory Sides of the Mare's Follicular and Oviduct Fluid.
Authors: Shen Yingchao, Ulaangerel Tseweendolmaa, Ren Hong, Davshilt Toli, Yi Minna, Li Xinyu, Xing Jingya, Du Ming, Bai Dongyi, Dugarjav Manglai, Bou Gerelchimeg
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Proteomic Profiling of Ovulatory versus Anovulatory Follicular Environments in Mares The follicular and oviduct fluids create the microenvironment governing oocyte maturation and early fertilisation events, yet their composition differs markedly depending on ovulatory competence. Shen and colleagues conducted a proteomic analysis comparing fluids harvested from the ovulatory (dominant) and anovulatory (subordinate) follicles of mares, alongside oviduct samples, to characterise the molecular basis of successful ovulation. Whilst oviduct fluid composition remained consistent between sides, follicular fluid revealed 71 proteins with differential abundance—predominantly a downregulation of 62 proteins in the ovulatory follicle and upregulation of 9 key proteins, with phospholipase A2 group IB (PLA2G1B) showing the greatest fold-change and potential involvement in meiotic competence. The functional analysis linked these differential proteins to oocyte meiosis, maturation and ovulation pathways, suggesting that the dominant follicle actively suppresses certain proteins whilst enriching others critical for reproductive success. For practitioners involved in equine assisted reproductive techniques, these findings offer mechanistic insights into in vitro maturation and fertilisation protocols, potentially identifying novel biomarkers or culture conditions that better replicate the ovulatory follicle's physiological advantages.
Read the full abstract on PubMed
Practical Takeaways
- •Understanding follicular fluid protein differences between ovulatory and anovulatory sides may improve optimization of equine in vitro reproductive protocols and fertility outcomes
- •PLA2G1B emerges as a potential biomarker or therapeutic target for enhancing horse IVM/IVF success rates
- •Follicular microenvironment composition appears critical to ovulation success, while oviduct fluid composition remains consistent regardless of ovulation status
Key Findings
- •71 differential abundance proteins identified between ovulatory and anovulatory follicular fluid, with 9 up-regulated and 62 down-regulated on the ovulatory side
- •No significant proteomic difference detected between oviduct fluids from ovulatory versus anovulatory sides
- •PLA2G1B identified as a newly discovered high-fold-change protein in ovulatory follicular fluid potentially influencing IVM/IVF efficacy
- •Up- and down-regulated proteins are largely associated with oocyte meiosis, maturation, and ovulation mechanisms