Sperm Selection through Microvesicle-Mediated ChemotaxisInduced by Follicular Fluid and Cumulus Cells

Selecting the most competent sperm is crucial for improving the success of intracytoplasmic sperm injection (ICSI). Chemotaxis-based sperm selection may facilitate the selection of spermatozoa with superior motility and fertilization capability. This study aimed to evaluate sperm selection based on chemotaxis induced by microvesicles (MVs) derived from follicular fluid (FF) and cumulus cells (CCs) using a simple microfluidic device.

In this experimental study, FF and CCs were collected during ovum pick-up from 10 women undergoing ICSI. MVs from both FF and CCs were isolated using the Exocib kit and characterized for particle size, polydispersity index, zeta potential, morphology, and protein content. To establish a chemoattractant gradient, MVs from FF and CCs, as well as progesterone, were incorporated into agar plates. Nine experimental groups were studied: FF- derived MVs (FF-MV, 5, 25, and 50 μg/ml), CC-derived MV (CC-MV, 5, 25, and 50 μg/ml), FF (50 μg/ml), progesterone (0.03 μM), and a control (agar without chemoattractant). Sperm selection was performed in a microfluidic system using semen samples from 20 normozoospermic men. Sperm concentration, motility, progressive motility, viability, and DNA integrity were analyzed following chemotaxis-based selection.

The isolated FF-and CC-derived MVs exhibited spherical morphology, a negative zeta potential, and were polydispersed. The progesterone-containing plates showed sustained release. No significant differences were observed between the CC-MV and control groups in sperm parameters (P=0.630). Plates supplemented with 50 μg/mL of FF-MV markedly improved sperm concentration (P=0.002), progressive motility (P=0.010), and DNA integrity (P=0.001) compared to the control group.

FF-MVs, particularly at 50 μg/ml, possess chemoattractant properties and could selectively enrich sperm populations with improved functional parameters. These findings highlight the potential of FF-MVs as a novel tool for high-quality sperm selection in the ICSI procedure.