For EV isolation, 2 ml of pre-centrifuged follicular samples were subjected to an ultracentrifugation procedure at 120,000 xg for 70 min at 4 OC using the Beckman SWTi55 rotor. The EVs pellet was washed with sterile PBS and then centrifuged again at 120,000 ×g for 70 min. Finally, EVs were resuspended in 500 µL of PBS and stored in −80 °C until further characterization and analysis. Small-RNA libraries were prepared for next-generation sequencing (NGS) using a TruSeq Small RNA Library Prep Kit (Illumina) according to the manufacturer's instructions.