Seminal plasma, and not sperm, induces time and concentration-dependent neutrophil extracellular trap release in donkeys.
Authors: Mateo-Otero Yentel, Zambrano Fabiola, Catalán Jaime, Sánchez Raúl, Yeste Marc, Miro Jordi, Fernandez-Fuertes Beatriz
Journal: Equine veterinary journal
Summary
# Editorial Summary Donkey reproduction presents a significant challenge in breeding programmes: artificial insemination with cryopreserved semen yields disappointingly low pregnancy rates, yet the underlying immunological mechanisms remain poorly understood compared to horses and cattle. Researchers investigated whether seminal plasma—the protein-rich fluid component of semen—triggers neutrophil extracellular trap (NET) formation in donkey endometrial tissues, as this phenomenon has been documented in other species and could explain both the robust uterine inflammatory response and poor fertilisation outcomes. The study found that seminal plasma, rather than spermatozoa themselves, induced time and concentration-dependent NET release, with the effect intensifying as plasma concentration increased and exposure time extended. This distinction matters significantly for practice: the inflammatory cascade triggered by semen components during AI may actively impair sperm viability and embryo establishment, suggesting that modifications to insemination protocols—such as seminal plasma removal or reduced semen dose strategies—warrant investigation to improve donkey breeding outcomes. Understanding these immunological barriers to successful reproduction opens avenues for optimising AI techniques and warrants consideration of species-specific differences when adapting equine breeding protocols to donkey management.
Read the full abstract on PubMed
Practical Takeaways
- •Poor pregnancy rates following frozen-thawed semen AI in donkeys may involve different immune mechanisms than in horses and cattle, suggesting species-specific handling protocols are needed
- •Understanding that seminal plasma components drive immune responses in donkeys could lead to improved semen processing or uterine management strategies for assisted reproduction
- •NETs may not be the primary factor limiting donkey fertility post-AI, warranting investigation of alternative sperm-immune interactions specific to this species
Key Findings
- •Seminal plasma, not sperm cells themselves, induces time and concentration-dependent neutrophil extracellular trap (NET) release in donkeys
- •Artificial insemination with frozen-thawed semen triggers large polymorphonuclear cell recruitment to the donkey uterus despite no documented NET formation
- •NET-mediated sperm entrapment occurs in cattle, horses, and humans but mechanism differs in donkeys