Effect of Bovine Follicular Fluid Small Extracellular Vesicles Isolated by Ultracentrifugation and Chromatography on In Vitro Oocyte Maturation and Embryo Development

Abstract

Small extracellular vesicles (sEVs) play a crucial role in intercellular communication and have demonstrated significant relevance in reproductive biotechnology, particularly in in vitro maturation (IVM) and bovine embryo production. This study evaluates the effects of bovine follicular fluid-derived extracellular vesicles (ffsEVs) isolated using two methods: ultracentrifugation (UC) and size-exclusion chromatography (SEC) on oocyte maturation and preimplantational embryonic development. Significant differences in the size of ffsEVs obtained by both isolation methods were noted, with UC-derived ffsEVs (UC ffsEVs) being smaller than those isolated by SEC (SEC ffsEVs). UC ffsEVs were more effective in upregulating critical oocyte quality genes, such as HSF1 and CPT1B. However, no significant differences were observed in embryonic developmental rates. Furthermore, the expression of genes associated with preimplantational embryonic quality revealed that only the SEC ffsEVs group exhibited a significant increase in IFNT1 and SOX2 levels, indicating an enhancement in embryonic quality. Notably, blastocysts derived from SEC ffsEVs also showed a higher total cell count compared to those from UC ffsEVs. No differences were found in other critical genes like GLUT1 and CDX2. These results suggest that the use of SEC ffsEVs could improve the in vitro embryo production process, highlighting the importance of the isolation method in determining the functional efficacy of ffsEVs according to research objectives.