Ovarian stimulation Altered Uterine Fluid Extracellular Vesicles miRNA Affecting Implantation in Rats

Abstract

Abstract Purpose: Uterine fluid (UF) extracellular vesicle (EV) miRNA may affect implantation and could be the potential biomarker of endometrial receptivity (ER). Ovarian stimulation (OS) could damage the ER but its mechanism is still unclear. Here, we evaluate the affections of OS on UF EV miRNA expression and implantation. Methods: Female rats were divided into three groups: natural cycle or injection with GnRH-a following HP-HMG or u-FSH and collected UF on the 5th day of gestation. The affinity membrane column was used to isolate EVs from UF, which was collected by flushing during implantation. EVs miRNAs were sequenced, and five among them were verified by qRT–PCR. Results: In OS groups, the implantation rate decreased (p<0.05), and the pinopode was damaged in the OS groups. The EVs were isolated from UF, and the differential expression key miRNAs were involved in several regulation pathways, such as cancer, endocrine, and cell cycles, which were correlated with ER and implantation. Among the miRNAs, miR-223-5p greatly differed and was most consistent with the sequencing results, followed by miR-223-3p and miR-98-5P. Conclusion: OS altered UF EVs miRNAs affecting implantation in rats, and miR-223 might be the key molecule. Our results enriched EV data in the fertility research field and broadened our knowledge of OS and implantation.