| Summary: | Exosomes are nano-sized vesicles with abundant nucleic acids, proteins, lipids, and other regulatory molecules. The aim of this study was to examine the effect of BOEC–Exo on bovine in vitro oocyte maturation and in vitro embryo development. We found that a 3% Exo supplementation to IVM media significantly enhanced the oocyte maturation and reduced the accumulation of ROS in MII-stage bovine oocytes. Oocyte maturation related genes (GDF9 and CPEB1) also confirmed that 3% Exo treatment to oocytes significantly (<i>p</i> < 0.05) enhanced the oocyte maturation. Next, we cultured bovine cumulus cells and assessed the effects of 3% Exo, which showed a reduced level of apoptotic proteins (caspase-3 and p-NF-κB protein expressions). Furthermore, we examined the gap junction (CX43 and CX37) and cumulus cells expansion related genes (HAS2, PTX3, and GREM1) in cumulus–oocyte complexes (COCs), and all those genes showed significantly (<i>p</i> < 0.05) higher expressions in 3% Exo-treated COCs as compared with the control group. Moreover, peroxisome proliferator-activated receptors (PPARs) and lipid metabolism-related genes (CPT1 and FABP3) were also analyzed in both the control and 3% Exo groups and the results showed significant (<i>p</i> < 0.05) enhancement in the lipid metabolism. Finally, the oocytes matured in the presence of 3% Exo showed a significantly higher rate of embryo development and better implantation potential. Finally, we concluded that Exo positively influenced bovine oocyte in vitro maturation and improved the early embryo’s developmental competence.
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