The role of extracellular vesicles in animal reproduction.

Infertility affects approximately one in six couples worldwide and remains a multifactorial condition influenced by genetic, physiological, and environmental factors. Despite remarkable advances in assisted reproductive technologies (ART), current therapeutic approaches often fail to address the underlying molecular mechanisms contributing to infertility. In recent years, extracellular vesicles (EVs) have emerged as key mediators of intercellular communication, capable of transferring bioactive molecules such as proteins, lipids, and nucleic acids between cells within the reproductive system. Evidence indicates that EVs derived from reproductive tissues-including the testis, epididymis, uterus, and oviduct-play essential roles in gametogenesis, fertilization, embryogenesis, and implantation by modulating gene expression and cellular signaling in recipient cells. Studies have demonstrated that epididymal EVs regulate sperm maturation and motility, while uterine and oviductal EVs enhance sperm function and embryo development. Furthermore, the ability to engineer EVs for therapeutic delivery offers a promising strategy to improve gamete and embryo quality, mitigate implantation failure, and enhance ART outcomes. Veterinary research has further underscored the potential of EVs in cryopreservation, oocyte maturation, and management of reproductive disorders across species. Nonetheless, challenges remain regarding standardization of isolation techniques, elucidation of molecular cargo, and understanding the mechanisms of EV-mediated effects. Future research integrating advanced omics, microfluidics, and bioengineering technologies may unlock the full clinical potential of EVs as diagnostic biomarkers and therapeutic agents in reproductive medicine.