Influence of Extracellular Vesicles from the Follicular Fluid of Young Women and Women of Advanced Maternal Age with Different miRNA Profiles on Sperm Functional Properties

We studied the effect of co-culturing of extracellular vesicles in the follicular fluid of young women and women of advanced maternal age on sperm motility. Vesicles were obtained by differential centrifugation. The sperm fraction was isolated from the seminal fluid of 18 patients (age 28-36 years). The spermatozoa were incubated with vesicles (1:2 ratio) for 60 or 120 min at 37°C in a CO2 incubator. A fraction of spermatozoa incubated without vesicles served as the control. After the incubation, the sperm samples were sedimented by centrifugation, fixed in 2.5% glutaraldehyde, and analyzed by transmission electron microscopy. RNA was isolated from the follicular fluid vesicles by column method followed by cDNA synthesis in a reaction mixture according to miScript II RT Kit protocol (Qiagen). After 60-min incubation with extracellular vesicles from the follicular fluid of women of advanced maternal age, the sperm motility and hyperactivation slightly changed in comparison with the group where incubation was performed with follicular fluid vesicles from young women and control group. Follicular fluid miRNA profiles in women of different ages varied, which suggests different functional compositions and effects of follicular fluid vesicles of different age groups on sperm characteristics. Transmission electron microscopy revealed differences in the interaction of follicular fluid vesicles from women of different age groups with spermatozoa. Further study of the effect of extracellular vesicles from the follicular fluid and analysis of their transcriptomic, proteomic, and metabolomic composition on sperm mobility and fertilizing ability will improve the effectiveness of assisted reproductive technology programs in patients with male infertility.