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Uterine peristalsis plays a vital role in fertility and female reproductive health. Although uterine peristalsis is thought to be correlated with some hormones and uterine pathologies, the physiological mechanisms underlying uterine peristalsis remain not quite clear. This study aimed to identify changes in miRNA in the endometrium of patients with abnormally high-frequency (hyper-) and low-frequency (hypo-) peristalsis to clarify whether miRNAs regulate uterine peristalsis. We used a miRNA microarray and RT-qPCR to identify changes in miRNA in endometrial tissue, a collagen gel contraction assay on co-cultured human endometrial stromal cells (ESCs) to analyze how the altered regulation of miRNAs influences uterine smooth muscle (USM) contraction, Western blots and other assays to elucidate the potential mechanisms involved. We found that among several differentially regulated miRNAs, miR-29c-3p was overexpressed in endometrial samples from patients with hypoperistalsis; oxytocin receptor (OXTR) expression was low in endometrial samples from patients with hypoperistalsis. Bioinformatic analysis and luciferase assays indicated that OXTR is a target of miR-29c-3p, which attenuates its expression. Additionally, downregulation of miR-29c-3p in ESC cultures increased the expression of aldo-keto reductase family 1, member C3 (AKR1C3) and increased the release of prostaglandin F2 alpha (PGF2α). Co-cultured ESCs overexpressing miR-29c-3p reduced USM cell contractions; the opposite tendency was found when ESCs were transfected with a miR-29c-3p inhibitor. To conclude, miR-29c-3p in endometrial cells regulates uterine contractility by attenuating the expression of OXTR and reducing PGF2α release.

We recently reported that electrical activation followed by secondary chemical activation greatly enhanced the developmental competence of in vitro matured porcine oocytes fertilized by intracytoplasmic sperm injection (ICSI). We hypothesized that sperm treatment with disulfide bond reducing agents will enhance the development competence of porcine embryos produced by this ICSI procedure. We examined the effects of glutathione (GSH), dithiothreitol (DTT), GSH or DTT in combination with heparin on sperm DNA structure, paternal chromosomal integrity, pronuclear formation, and developmental competence of in vitro matured porcine oocytes after ICSI. Acridine orange staining and flow cytometry based sperm chromatin structure assay were used to determine sperm DNA integrity by calculating the cells outside the main population (COMP αT). No differences were observed in COMP αT values among GSH-treated and control groups. COMP αT values in GSH-treated groups were significantly lower than that in DTT-treated groups. Following ICSI, GSH treatments did not significantly alter paternal chromosomal integrity. Paternal chromosomal integrity in sperm treated with DTT plus or minus heparin was also the lowest among all groups. GSH-treated sperm yielded the highest rates of normal fertilization and blastocyst formation, which were significantly higher than that of control and DTT-treated groups. The majority of blastocysts derived from control and GSH-treated spermatozoa were diploid, whereas blastocysts derived from DTT-treated spermatozoa were haploid. In conclusion, sperm treatment with GSH enhanced the developmental capacity of porcine embryos produced by our optimized ICSI procedure.