Extracellular vesicles in bovine reproduction: their journey from gametogenesis to pregnancy

Extracellular vesicles (EVs), including exosomes and microvesicles, play a pivotal role in bovine reproduction by mediating communication between gametes, the developing embryo, and the maternal reproductive tract. These vesicles act as carriers of bioactive molecules, such as microRNAs, mRNAs, lipids, and proteins that regulate processes from gametogenesis to early pregnancy. The embryo-maternal dialogue, mediated by EVs, shapes the oviductal and uterine microenvironments, ensuring proper fertilization, embryonic development, and implantation. However, in vitro systems often lack the complexity of in vivo interactions, resulting in reduced embryo quality and developmental competence. This review summarizes recent findings on EV-mediated mechanisms of intercellular communication during the pre-implantation stages and discusses current challenges and emerging opportunities in developing in vitro models that more closely replicate physiological conditions within the bovine reproductive tract. Furthermore, it highlights the potential of EVs as diagnostic and therapeutic tools for improving reproductive efficiency and outcomes in cattle.