Given that ovarian stimulation is vital for assisted reproductive technology (ART) and results in elevated serum estrogen levels, exploring the impact of elevated estrogen exposure on oocytes and embryos is necessary. We investigated the effects of various ovarian stimulation treatments on oocyte and embryo morphology and gene expression using a mouse model and estrogen-treated mouse embryonic stem cells (mESCs). Female C57BL/6J mice were subjected to two types of conventional ovarian stimulation and ovarian hyperstimulation; mice treated with only normal saline served as controls. Hyperstimulation resulted in high serum estrogen levels, enlarged ovaries, an increased number of aberrant oocytes, and decreased embryo formation. The messenger RNA (mRNA)‍-sequencing of oocytes revealed the dysregulated expression of lysine-specific demethylase 6b (Kdm6b), which may be a key factor indicating hyperstimulation-induced aberrant oocytes and embryos. In vitro, Kdm6b expression was downregulated in mESCs treated with high-dose estrogen; treatment with an estrogen receptor antagonist could reverse this downregulated expression level. Furthermore, treatment with high-dose estrogen resulted in the upregulated expression of histone H3 lysine 27 trimethylation (H3K27me3) and phosphorylated H2A histone family member X (γ-H2AX). Notably, knockdown of Kdm6b and high estrogen levels hindered the formation of embryoid bodies, with a concomitant increase in the expression of H3K27me3 and γ-H2AX. Collectively, our findings revealed that hyperstimulation-induced high-dose estrogen could impair the demethylation of H3K27me3 by reducing Kdm6b expression. Accordingly, Kdm6b could be a promising marker for clinically predicting ART outcomes in patients with ovarian hyperstimulation syndrome.
Female ; Mice ; Demethylation/drug effects* ; Embryonic Stem Cells ; Estrogens/administration & dosage* ; Gene Expression/drug effects* ; Histones/metabolism* ; Jumonji Domain-Containing Histone Demethylases/metabolism* ; Mice, Inbred C57BL ; Oocytes ; Ovary/drug effects* ; Reproductive Techniques, Assisted ; Animals

Polycystic ovary syndrome (PCOS) is the predominant cause of subfertility in reproductive-aged women; however, its pathophysiology remains unknown. Neurotensin (NTS) is a member of the gut-brain peptide family and is involved in ovulation; its relationship with PCOS is unclear. Here, we found that NTS expression in ovarian granulosa cells and follicular fluids was markedly decreased in patients with PCOS. In the in vitro culture of cumulus-oocyte complexes, the neurotensin receptor 1 (NTSR1) antagonist SR48692 blocked cumulus expansion and oocyte meiotic maturation by inhibiting metabolic cooperation and damaging the mitochondrial structure in oocytes and surrounding cumulus cells. Furthermore, the ERK1/2-early growth response 1 pathway was found to be a key downstream mediator of NTS/NTSR1 in the ovulatory process. Animal studies showed that in vivo injection of SR48692 in mice reduced ovulation efficiency and contributed to irregular estrus cycles and polycystic ovary morphology. By contrast, NTS partially ameliorated the ovarian abnormalities in mice with dehydroepiandrosterone-induced PCOS. Our findings highlighted the critical role of NTS reduction and consequent abnormal NTSR1 signaling in the ovulatory dysfunction of PCOS, suggesting a potential strategy for PCOS treatment.
Polycystic Ovary Syndrome/physiopathology* ; Female ; Animals ; Neurotensin/metabolism* ; Receptors, Neurotensin/antagonists & inhibitors* ; Mice ; Ovulation/drug effects* ; Humans ; Granulosa Cells/metabolism* ; Adult ; Oocytes/metabolism* ; MAP Kinase Signaling System ; Signal Transduction ; Follicular Fluid/metabolism* ; Disease Models, Animal ; Gonadotropin-Releasing Hormone/analogs & derivatives*

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

Epigallocatechin gallate (EGCG), the predominant polyphenol in green tea, exerts a spectrum of physiological activities, including antioxidant, anticancer, and anti-inflammatory effects. Emerging research underscores the significance of EGCG in modulating oocyte aging. EGCG can enhance antioxidant defenses, improve mitochondrial functions, and inhibit apoptotic pathways, thereby retarding the aging of oocytes. This review delineates the main molecular features of EGCG and expounds its regulatory mechanisms concerning oocyte aging, enriching the knowledge on the role of EGCG in the amelioration of oocyte aging.
Catechin/pharmacology* ; Oocytes/metabolism* ; Humans ; Animals ; Antioxidants/pharmacology* ; Female ; Cellular Senescence/drug effects* ; Tea/chemistry* ; Apoptosis/drug effects*

As the number of young cancer survivors increases, quality of life after cancer treatment is becoming an ever more important consideration. According to a report from the American Cancer Society, approximately 810,170 women were diagnosed with cancer in 2015 in the United States. Among female cancer survivors, 1 in 250 are of reproductive age. Anticancer therapies can result in infertility or sterility and can have long-term negative effects on bone health, cardiovascular health as a result of reproductive endocrine function. Fertility preservation has been identified by many young patients diagnosed with cancer as second only to survival in terms of importance. The development of fertility preservation technologies aims to help patients diagnosed with cancer to preserve or protect their fertility prior to exposure to chemo- or radiation therapy, thus improving their chances of having a family and enhancing their quality of life as a cancer survivor. Currently, sperm, egg, and embryo banking are standard of care for preserving fertility for reproductive-age cancer patients; ovarian tissue cryopreservation is still considered experimental. Adoption and surrogate may also need to be considered. All patients should receive information about the fertility risks associated with their cancer treatment and the fertility preservation options available in a timely manner, whether or not they decide to ultimately pursue fertility preservation. Because of the ever expanding number of options for treating cancer and preserving fertility, there is now an opportunity to take a precision medicine approach to informing patients about the fertility risks associated with their cancer treatment and the fertility preservation options that are available to them.
Adult Stem Cells ; Cell Culture Techniques ; Cryopreservation/*methods ; *Embryo, Mammalian ; Female ; Fertility Preservation/*methods ; Humans ; Neoplasms/drug therapy/*therapy ; *Oocytes ; Ovarian Follicle/drug effects/metabolism/transplantation ; *Ovary/transplantation ; Ovulation Induction/methods ; Precision Medicine

BACKGROUNDL-proline is a natural, nontoxic cryoprotectant that helps cells and tissues to tolerate freezing in a variety of plants and animals. The use of L-proline in mammalian oocyte cryopreservation is rare. In this study, we explored the cryobiological characteristics of L-proline and evaluated its protective effect in mouse oocyte cryopreservation.

METHODSThe freezing property of L-proline was detected by Raman spectroscopy and osmometer. Mature oocytes obtained from 8-week-old B6D2F1 mice were vitrified in a solution consisting various concentration of L-proline with a reduced proportion of dimethyl sulfoxide (DMSO) and ethylene glycol (EG), comparing with the control group (15% DMSO and 15% EG without L-proline). The survival rate, 5-methylcytosine (5-mC) expression, fertilization rate, two-cell rate, and blastocyst rate in vitro were assessed by immunofluorescence and in vitro fertilization. Data were analyzed by Chi-square test.

RESULTSL-proline can penetrate the oocyte membrane within 1 min. The osmotic pressure of 2.00 mol/L L-proline mixture is similar to that of the control group. The survival rate of the postthawed oocyte in 2.00 mol/L L-proline combining 7.5% DMSO and 10% EG is significantly higher than that of the control group. There is no difference of 5-mC expression between the L-proline combination groups and control. The fertilization rate, two-cell rate, and blastocyst rate in vitro from oocyte vitrified in 2.00 mol/L L-proline combining 7.5% DMSO and 10% EG solution are similar to that of control.

CONCLUSIONSIt indicated that an appropriate concentration of L-proline can improve the cryopreservation efficiency of mouse oocytes with low concentrations of DMSO and EG, which may be applicable to human oocyte vitrification.

Animals ; Cryopreservation ; methods ; Cryoprotective Agents ; pharmacology ; Female ; Fertilization in Vitro ; Hydrogen-Ion Concentration ; Male ; Mice ; Oocytes ; drug effects ; Osmotic Pressure ; Proline ; pharmacology ; Spectrum Analysis, Raman ; Vitrification

This study was conducted to investigate the effects of rapamycin treatment during in vitro maturation (IVM) on oocyte maturation and embryonic development after parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) in pigs. Morphologically good (MGCOCs) and poor oocytes (MPCOCs) were untreated or treated with 1 nM rapamycin during 0-22 h, 22-42 h, or 0-42 h of IVM. Rapamycin had no significant effects on nuclear maturation and blastocyst formation after PA of MGCOCs. Blastocyst formation after PA was significantly increased by rapamycin treatment during 22-42 h and 0-42 h (46.6% and 46.5%, respectively) relative to the control (33.3%) and 0-22 h groups (38.6%) in MPCOCs. In SCNT, blastocyst formation tended to increase in MPCOCs treated with rapamycin during 0-42 h of IVM relative to untreated oocytes (20.3% vs. 14.3%, 0.05 < p < 0.1), while no improvement was observed in MGCOCs. Gene expression analysis revealed that transcript abundance of Beclin 1 and microtubule-associated protein 1 light chain 3 mRNAs was significantly increased in MPCOCs by rapamycin relative to the control. Our results demonstrated that autophagy induction by rapamycin during IVM improved developmental competence of oocytes derived from MPCOCs.
Animals ; Embryonic Development/*drug effects ; Female ; In Vitro Oocyte Maturation Techniques/veterinary ; Nuclear Transfer Techniques/*veterinary ; Oocytes/growth & development ; *Parthenogenesis ; Sirolimus/*pharmacology ; Sus scrofa/*growth & development/metabolism

The effects of mouse oocyte vitrification on mitochondrial membrane potential and distribution were explored in this study. The collected mouse oocytes were randomly divided into vitrification and control groups. Ethylene glycol (EG) and dimethylsulphoxide (DMSO) were used as cryoprotectants in the vitrification group. The mitochondrial function and distribution in the oocytes were examined by using the fluorescent probes, JC-1 and Mito Tracker green. The results showed that the ratio of red to green fluorescence in mouse oocytes was significantly decreased after thawing in the vitrification group as compared with the control group (1.28 vs. 1.70, P<0.05). The percentage of polarized distribution of the mitochondria in oocytes was conspicuously reduced in the vitrification group when compared with the control group (31% vs. 63%, P<0.05). It was suggested that vitrification significantly affects the mitochondrial function and distribution in oocytes and reduces the potential of oocyte fertilization and embryo development.
Animals ; Cryopreservation ; methods ; Cryoprotective Agents ; pharmacology ; Dimethyl Sulfoxide ; pharmacology ; Ethylene Glycol ; pharmacology ; Female ; Fluorescent Dyes ; metabolism ; Membrane Potential, Mitochondrial ; drug effects ; physiology ; Mice ; Microscopy, Fluorescence ; Mitochondria ; drug effects ; metabolism ; Oocytes ; drug effects ; physiology ; Temperature ; Vitrification

OBJECTIVETo search for an optimal activation protocol by comparing the chemical activation effects of single-activator and combined activation protocols on mouse oocytes following injection of round spermatids (ROSI) from spermatogenic cells cultured in vitro.

METHODSUsing different concentrations of ethanol, ionomycin (Ion), calcium ionophore A23187 (CIA), strontium chloride (SrCl2), cycloheximide (CHX), and 6-dimethylaminopurine (6-DMAP) , we activated post-ROSI oocytes for different times, and activated them by combined protocols at optimal concentrations and action times according to different activation channels. We compared the activation effects of single-activator and combined activation protocols by comparing the rates of fertilization, cleavages, and morulas and blastocysts.

RESULTSWith a single activator, the optimal protocols of different activators were as follows: 7% ethanol for 6 min, 5 micromol/L CIA for 5 min, 5 micromol/L Ion for 5 min, 2 mmol/L 6-DMAP for 2 h, 10 mmol/L SrCl2 for 1.5 h, and 10 microg/ml CHX for 1.5 h, among which 10 mmol/L SrCl2 for 1.5 h achieved the highest rate of morulas and blastocysts, significantly better than CHX (P < 0.05) but with no remarkable difference from other activators. The ethanol + 6-DMAP group showed a significantly higher rate of morulas and blastocysts (29.63%) than all other combined activation groups and single-activator groups except SrCl2 (P < 0.05), and it also exhibited higher rates of normal fertilization, cleavages and morula than the SrCl2 group, but with no significant difference.

CONCLUSIONThe single-activator 10 mmol/L SrCl2 for 1.5 h and the combined activation of 7% ethanol for 6 min + 2 mmol/L 6-DMAP for 2 h are the optimal protocols for chemical activation of mouse oocytes following ROSI, and the combined activation of ethanol + 6-DMAP is even superior to the single-activator protocol.

Animals ; Cycloheximide ; pharmacology ; Female ; Fertilization in Vitro ; Ionomycin ; pharmacology ; Male ; Mice ; Mice, Inbred Strains ; Oocytes ; cytology ; drug effects ; Spermatids ; cytology ; drug effects

OBJECTIVETo observe the effect of Kuntai Capsule (KC) on the number of retrieved oocytes, the quality of high-quality oocytes and embryos in in vitro fertilization of poor ovarian response (POR) patients.

METHODSTotally 70 POR patients preparing for in vitro fertilization-embryo transfer (IVF-ET) were randomly assigned to the observation group and the control group, 35 cases in each group. KC was administered to patients in the observation group in the preparation cycle (i.e., three menstrual cycles before IVF-ET) and during the superovulation process. Those in the control group took placebo during this period. Before and after medication the improvement of Shen yin deficiency syndrome (SYDS) was observed in the two groups. The basal follicle-stimulating hormone (bFSH), luteinizing hormone (LH), estradiol (E2), anti-Mullerian hormone (AMH), the ratio of FSH to LH, and antral follicle count (AFC) were observed. Besides, the E2 level of a single ovum on the day of HCG injection, the number of retrieved oocytes, the high-quality oocyte rate, and the high-quality embryos were observed.

RESULTSCompared with the control group, the SYDS, decreased bFSH and LH levels, increased ACF numbers, the E2 level of a single ovum on the day of HCG injection, the number of retrieved oocytes, high-quality oocytes, and high-quality embryos were superior in the observation group (P < 0.05). There was no statistical difference in the decreased FSH/LH level (P > 0.05). E2 and AMH increased after medication of KC in the observation group, while they decreased after administration of placebos in the control group. There was statistical difference in the post-pre treatment difference of E2 and AMH between the two groups (P < 0.05).

CONCLUSIONKC could increase the number of retrieved oocytes, and elevate the quality of occytes and embryos in the IVF-ET.

Adult ; Drugs, Chinese Herbal ; pharmacology ; Embryo Transfer ; Female ; Fertilization in Vitro ; Humans ; Oocyte Retrieval ; Oocytes ; drug effects ; Pregnancy