The production of high-quality oocytes requires precisely orchestrated intercellular communication. Extracellular vesicles (EVs) are cell-derived nanoparticles that play a vital role in the transfer of bioactive molecules, which has gained much attention in the field of diagnosis and treatment. Over the past ten years, the participation of EVs in the reproductive processes of oocytes has been broadly studied and has shown great potential for elucidating the intricacies of female reproductive health. This review provides an extensive discussion of the influence of EVs on oocytes, emphasizing their involvement in normal physiology and altered cargo under pathological conditions. In addition, the positive impact of therapeutic EVs on oocyte quality and their role in alleviating ovarian pathological conditions are summarized.
Humans ; Extracellular Vesicles/physiology* ; Oocytes/cytology* ; Female ; Animals ; Cell Communication/physiology*

Bone morphogenetic proteins (BMPs) are multifunctional growth factors of the transforming growth factor β (TGF-β) superfamily. They regulate steroid secretion from mammalian granulosa cells, promote granulosa cell survival and proliferation, and inhibit follicular atresia, luteinization, and granulosa cell apoptosis, thereby promoting the development and maturation of mammalian follicles. At the same time, BMPs play an important role in embryonic morphogenesis, induction of uterine receptivity, and blastocyst attachment. This paper describes the effects of BMPs on mammalian follicular and embryonic development and the roles of BMPs in female reproduction, focusing on the process in which BMPs promote follicular maturation by regulating steroid secretion from granulosa cells during mammalian oocyte maturation. This review aims to provide a reference for further research on mammalian oocyte culture and improvement of reproductive efficiency in female animals.
Animals ; Embryonic Development/drug effects* ; Female ; Bone Morphogenetic Proteins/pharmacology* ; Reproduction/physiology* ; Humans ; Granulosa Cells/cytology* ; Oocytes

The chromosomal aneuploidy in oocytes is one of main causes of abortion and neonatal birth defects.It is mainly due to the premature separation of sister chromatid caused by the loss of Cohesin protein complex and the non-disjunction sister chromatids caused by abnormal microtubule dynamics aneuploidy.As a pathway of protein post-translational modification,SUMO modification(or SUMOylation)involves many physiological regulation processes including cell proliferation,differentiation,apoptosis,and cycle regulation.In the oocytes,SUMOylation can regulate the localization of Cohesin protein complex on the chromosome to affect the chromosomal aneuploidy in oocytes caused by premature separation of sister chromatid.On the other hand,SUMOylation can regulate the microtubule dynamics to affect the chromosomal aneuploidy in oocytes caused by non-disjunction sister chromatids.Therefore,SUMOylation plays an important role in regulating the chromosomal aneuploidy of oocytes;the exact mechanisms via which the SUMOylated substrates affect aneuploidy in oocytes remain unclear.This articles reviews the roles of SUMOylation in premature separation and non-isolated chromatid aneuploidy in oocyte from the effects of SUMOylationon Cohesin protein complex and microtubule dynamics.
Aneuploidy ; Cell Cycle Proteins ; Chromatids ; Chromosomal Proteins, Non-Histone ; Chromosome Segregation ; Humans ; Microtubules ; Oocytes ; cytology ; Sumoylation

Oocyte-like cells (OLC) can be generated by stem cells after the induction and differentiation in vitro, and maturated when transplanted in vivo to improve the development potential. Human amniotic fluid stem cells (hAFSC) were cultured for 10 days in porcine follicle fluid (pFF) that was extracted from the medium follicle with high levels of hormones and Bmp 15 protein. After the induction, the cell aggregates showed the germ cell-like cells and produced the germ cell marker oct4, and triggered epigenetic changes with high expression of methylation transferase gene dnmt3b. The cell aggregates were packaged into porcine theca folliculi to form grafts, which were then transplanted into mouse renal capsule. After one month of transplantation, the morphology of OLC from a graft was not only similar to oocytes, but also expressed the germ cells markers (oct4, nanog, stella, ifitm3, dazl, nanos3, bmp15, and gd9). The results demonstrate that the in vivo differentiation model was useful for OLC development.
Amniotic Fluid ; cytology ; Animals ; Biomarkers ; Cell Differentiation ; Female ; Humans ; Mice ; Oocytes ; cytology ; Ovarian Follicle ; Stem Cells ; cytology ; Swine

OBJECTIVETo evaluate the safety and risk of cryopreservation in female fertility preservation.

DATA SOURCESThe data analyzed in this review were the English articles from 1980 to 2013 from journal databases, primarily PubMed and Google scholar. The criteria used in the literature search show as following: (1) human; embryo; cryopreservation/freezing/vitrification, (2) human; oocyte/immature oocyte; cryopreservation/ freezing/vitrification, (3) human; ovarian tissue transplantation; cryopreservation/freezing/vitrification, (4) human; aneuploidy/DNA damage/epigenetic; cryopreservation/freezing/vitrification, and (5) human; fertility preservation; maternal age.

STUDY SELECTIONThe risk ratios based on survival rate, maturation rate, fertilization rate, cleavage rate, implantation rate, pregnancy rate, and clinical risk rate were acquired from relevant meta-analysis studies. These studies included randomized controlled trials or studies with one of the primary outcome measures covering cryopreservation of human mature oocytes, embryos, and ovarian tissues within the last 7 years (from 2006 to 2013, since the pregnancy rates of oocyte vitrification were significantly increased due to the improved techniques). The data involving immature oocyte cryopreservation obtained from individual studies was also reviewed by the authors.

RESULTSVitrifications of mature oocytes and embryos obtained better clinical outcomes and did not increase the risks of DNA damage, spindle configuration, embryonic aneuploidy, and genomic imprinting as compared with fresh and slow-freezing procedures, respectively.

CONCLUSIONSBoth embryo and oocyte vitrifications are safe applications in female fertility preservation.

Cryopreservation ; methods ; Female ; Humans ; Oocytes ; cytology ; Ovary ; cytology ; Pregnancy

BACKGROUNDOocyte vitrification is widely used throughout the world, but its clinical efficacy is inconsistent and depends on the vitrification media. This study compared the developmental potential and clinical results of in vivo matured oocytes cryopreserved with different vitrification media.

METHODSThis retrospective study involved vitrified-warmed oocytes at one in vitro fertilization laboratory. Vitrification media kits comprised the MC kit (ethylene glycol [EG] plus 1,2-propanediol [PROH]), the KT kit (EG plus dimethyl sulphoxide [DMSO]), and the Modified kit (EG plus DMSO and PROH kit). Rates of oocyte survival and subsequent developmental potential were recorded and analyzed. The t-test and the Chi-square test were used to evaluate each method's efficacy.

RESULTSOocyte survival rate was significantly higher for the Modified kit (92.0%) than for the MC kit (88.2%) (P < 0.05) and the KT kit (77.3%) (P < 0.001). The rate of high-quality embryo development in the Modified kit group (35.8%) was significantly higher than in the MC kit group (29.0%) and the KT kit group (28.3%) (P < 0.001). No significant differences were observed in the clinical pregnancy and implantation rates among the MC, KT, and Modified kit groups (37.2% vs. 30.2% vs. 39.6%; 21.9% vs. 18.8% vs. 27.4%, respectively) (P > 0.05). The high-quality embryo rate per warmed oocyte was significantly higher (23.4%) in the Modified kit group than in the other groups (P < 0.001). The embryo utilization and live birth rates per warmed oocyte were the highest in the Modified kit group, but not significantly (P > 0.05).

CONCLUSIONSModified vitrification media are efficient for oocyte vitrification and, with further verification, may be able to replace commercially available media in future clinical applications.

Adult ; Cryopreservation ; methods ; Female ; Fertilization in Vitro ; methods ; Humans ; In Vitro Oocyte Maturation Techniques ; methods ; Oocytes ; cytology ; Pregnancy ; Retrospective Studies ; Vitrification

INTRODUCTIONThe aim of this study was to determine the effect of a high-fat diet (HFD) on oocyte maturation and quality in a mouse model.

METHODSFemale BALB/c mice were allocated to one of the following groups: (a) control group (n = 40), which received a controlled diet; or (b) HFD group (n = 40), which received an HFD for 12 weeks. Sections of the ovary were examined histologically. The number of follicles and corpora lutea were counted. In vitro maturation and in vitro fertilisation (IVF) were assessed in germinal vesicle (GV) and metaphase II (MII) oocytes, respectively. The expression of bone morphogenetic protein 15 (BMP15) and leptin receptor genes in GV and MII oocytes was evaluated using reverse transcription real-time polymerase chain reactions.

RESULTSIn the HFD group, there was a decreased number of primordial and Graafian follicles, as well as corpora lutea (p < 0.05). The rate of oocyte development to the MII stage was also reduced (p < 0.001). Cumulus expansion was observed more frequently in the control group than the HFD group (p < 0.05). The IVF rate in the HFD group was lower than that in the control group (p < 0.05). In the HFD group, BMP15 and leptin receptor genes were upregulated in the GV stage (p > 0.05) and MII stage (p < 0.05), compared to the control group.

CONCLUSIONAn HFD reduces folliculogenesis in the primordial and Graafian stages, in vitro maturation and in vitro fertilisation rates, as well as oocyte quality in mice.

Animals ; Body Weight ; Bone Morphogenetic Protein 15 ; metabolism ; Corpus Luteum ; pathology ; Diet, High-Fat ; Female ; Fertility ; Fertilization in Vitro ; methods ; Gene Expression Regulation ; Metaphase ; Mice ; Mice, Inbred BALB C ; Obesity ; complications ; Oocytes ; cytology ; pathology ; Ovarian Follicle ; pathology ; Ovary ; metabolism ; pathology ; Photography ; Polymerase Chain Reaction ; Receptors, Leptin ; metabolism

Calcium Ionophores ; metabolism ; Female ; Fertilization in Vitro ; adverse effects ; Humans ; Infant, Newborn ; Karyotype ; Male ; Oocytes ; cytology ; metabolism ; Sperm Injections, Intracytoplasmic ; adverse effects

This prospective study investigated the relationship between anti-Mullerian hormone (AMH) level in the follicular fluid (FF) and the quality of the oocyte and embryo. A total of 65 FF samples from 54 women were included in this study. FF was collected from the largest preovulatory follicle sized> or =20 mm of mean diameter from each ovary. Samples were divided into 3 groups according to the FF AMH levels: below the 33th percentile (low group, FF AMH<2.1 ng/mL, n=21), between the 33th and the 67th percentile (intermediate group, FF AMH=2.1-3.6 ng/mL, n=22), and above the 67th percentile (high group, FF AMH>3.6 ng/mL, n=22). The quality of the ensuing oocytes and embryos was evaluated by fertilization rate and embryo score. FF AMH levels correlated positively with the matched embryo score on day 3 after fertilization (r=0.331, P=0.015). The normal fertilization rate was significantly lower in the low group than in the intermediate group (61.9% vs. 95.5% vs. 77.3%, respectively, P=0.028). Our results suggest that the FF AMH level could be a predictor of the ensuing oocyte and embryo quality.
Adult ; Anti-Mullerian Hormone/*analysis ; Embryo, Mammalian/*cytology ; Female ; Fertilization in Vitro ; Follicular Fluid/*metabolism ; Humans ; Oocytes/cytology ; Prospective Studies

BACKGROUNDIt is still unclear whether the vitrification procedure itself is associated with the incidence of abnormal DNA methylation during oocytes vitrification. The purpose of this study was to evaluate the epigenetic profile of mouse oocytes, which went through vitrification either at a mature stage or at an immature stage following in vitro maturation (IVM) by analyzing the global DNA methylation.

METHODSMetaphase II (M II) stage and germinal vesicle (GV) stage oocytes were collected from adult female mice and were vitrified respectively. The M II oocytes were assessed for cryo-survival and global DNA methylation. The GV oocytes were assessed for cryo-survival and only the surviving GV oocytes were cultured in vitro for subsequent assessment of global DNA methylation in mature oocytes. In vivo matured fresh M II oocytes without undergoing vitrification were used as control. The level of global DNA methylation in the M II oocytes was then examined by immunofluorescence using an anti-5-methylcytosine (anti-5-MeC) monoclonal antibody and fluorescein isothiocyanate (FITC)-conjugated goat anti-mouse IgG under a laser scanning confocal microscope.

RESULTSIn terms of the effect of vitrification on global DNA methylation status in matured oocytes, in the M II-v group, all the examined oocytes (90/90) were found with hypermethylation, including 63.3% (57/90) of them displaying DNA methylation of a very high level, 25.6% (23/90) with a high level, and 11.1% (10/90) with an intermediate level, whereas in the GV-v group, all the matured oocytes (129/129) were also examined with hypermethylation, including 67.4% (87/129) of them displaying DNA methylation of a very high level, 23.3% (30/129) with a high level, and 9.3% (12/129) with an intermediate level. Statistically, it was similar between both groups, which were similar to the control: 68.6% (83/121) of fresh M II oocytes displayed DNA methylation of a very high level, 21.5% (26/121) with a high level, and 9.9%(12/121) with an intermediate level (P > 0.05). In terms of the effect of IVM on global DNA methylation status in matured oocytes, in the in vivo matured oocytes group, all oocytes examined (94/94) were found with hypermethylation, including 80.9% (76/94) displaying DNA methylation of a very high level and 19.1% (18/94) with a high level, whereas in the in vitro matured oocytes group, all oocytes examined (69/69) were also found with hypermethylation: 85.2% (56/69) of them displayed with DNA methylation of very high level, 11.9% (11/69) with high level, and 2% (2/69) with intermediate level. This result was similar to that in in vivo matured fresh M II oocytes (P > 0.05).

CONCLUSIONThe vitrification procedure at GV stage does not induce widespread alteration of global DNA methylation status of mouse oocytes subsequently matured in vitro.

Animals ; DNA Methylation ; physiology ; Female ; Fertilization in Vitro ; Mice ; Microscopy, Confocal ; Oocytes ; cytology ; metabolism ; Vitrification