Oviduct epithelial cell-derived extracellular vesicles promote the developmental competence of IVF porcine embryos

Assisted reproductive technology has increased the efficiency of animal reproduction. However, polyspermy is a significant limitation of porcine in vitro fertilization (IVF). Therefore, reducing the polyspermy rate and improving monospermic embryos is crucial. Recent studies have reported that oviductal fluid, along with its contents of extracellular vesicles (EVs), enhanced the fertilization process and supported embryo development. Consequently, the present study investigated the effects of porcine oviduct epithelial cells (OEC-EVs) on sperm-oocyte interactions during porcine IVF and evaluated in vitro embryo developmental competence outcomes. During IVF embryo development, the cleavage rate was significantly higher in the group treated with 50 ng/ml OEC-EVs compared with the control group (67.6 +/- 2.5 vs. 57.3 +/- 1.9; P<0.05). Furthermore, the OEC-EV group had significantly more embryos (16.4 +/- 1.2 vs. 10.2 +/- 0.8; P<0.05), and the polyspermy rate significantly decreased (32.9 +/- 2.5 vs. 43.8 +/- 3.1; P<0.05) compared with that of the control group. Additionally, the fluorescence intensities of cortical granules (3.56 +/- 0.47 vs. 2.15 +/- 0.24; P<0.05) and active mitochondria (8.14 +/- 0.34 vs. 5.96 +/- 0.38; P<0.05) were significantly higher in the OEC-EV group compared with those in the control group. In conclusion, OEC-EV adsorption and penetration crosstalk between sperm and oocytes was observed. OEC-EV treatment was demonstrated to significantly improve the concentration and distribution of cortical granules in oocytes. Furthermore, OEC-EVs also increased oocyte mitochondrial activity, reduced polyspermy and increased the IVF success rate.