Rationale:This case report describes a couple with recurrent fertilization failure despite undergoing multiple cycles of intracytoplasmic sperm injection(ICSI).The principal clinical concern was suspected oocyte activ...Rationale:This case report describes a couple with recurrent fertilization failure despite undergoing multiple cycles of intracytoplasmic sperm injection(ICSI).The principal clinical concern was suspected oocyte activation deficiency(OAD),in which fertilization is impeded due to the oocyte’s inability to initiate embryogenesis,commonly attributed to inadequate intracellular calcium(Ca^(2+))release following sperm injection.Patient concerns:The couple repeatedly experienced complete or near-complete fertilization failure in previous ICSI cycles,raising suspicion of an underlying oocyte activation defect.Diagnosis:Based on the repeated absence of fertilization post-ICSI and clinical history,a diagnosis of suspected OAD leading to recurrent ICSI fertilization failure was considered.Interventions:Artificial oocyte activation(AOA)using the calcium ionophore A23187 was performed.After ICSI,unfertilized oocytes were exposed to the ionophore to induce Ca^(2+)influx,simulating physiological calcium oscillations essential for oocyte activation.The efficacy of intervention was evaluated through subsequent embryonic development,morphological grading,and chromosomal integrity.Outcomes:Following AOA treatment,successful oocyte activation occurred,resulting in the formation of high-grade embryos with normal developmental progression.Chromosomal analysis revealed no detectable abnormalities,indicating genomic stability.Lessons:Calcium ionophore–mediated AOA may serve as an effective adjunct in cases of recurrent ICSI failure attributed to OAD.This case highlights the importance of individualized therapeutic strategies in assisted reproduction;however,further research is needed to refine protocols,validate broader clinical efficacy,and assess long-term safety,including potential epigenetic risks.展开更多
Meiotic resumption in mammalian oocytes involves nuclear and organelle structural changes,notably the chromatin configuration transition from a non-surrounding nucleolus(NSN)to surrounding nucleolus(SN)in germinal ves...Meiotic resumption in mammalian oocytes involves nuclear and organelle structural changes,notably the chromatin configuration transition from a non-surrounding nucleolus(NSN)to surrounding nucleolus(SN)in germinal vesicle oocytes.In the current study,we found that nuclear speckles(NSs),a subnuclear structure mainly composed of serine-arginine(SR)proteins,changed from a diffuse spotted distribution in mouse NSN oocytes to an aggregated pattern in SN oocytes.We also found that the SR protein-specific kinase 1(SRPK1),an enzyme that phosphorylates SR proteins,co-localized with NSs at the SN stage,and that NSN oocytes failed to transition to SN oocytes after the inhibition of SRPK1 activity.Furthermore,the typical structure of the chromatin ring around the nucleolus in SN oocytes collapsed after treatment with an SRPK1 inhibitor.Mechanistically,phosphorylated SR proteins were found to be related to chromatin as shown by a salt extraction experiment,and in situ DNaseⅠassay showed that the accessibility of chromatin was enhanced in SN oocytes when SRPK1 was inhibited,accompanied by a decreased repressive modification on histone and the abnormal recurrence of a transcriptional signal.In conclusion,our results indicated that SRPK1-regulated phosphorylation of SR proteins was involved in the NSN-SN transition and played an important role in maintaining the condensed nucleus of SN oocytes via interacting with chromatin.展开更多
Objective:To evaluate the effect of glutathione(GSH)supplementation in maturation and adaptation media on oocyte development,embryo quality,and oocyte viability after vitrification.Methods:The GSH concentrations were ...Objective:To evaluate the effect of glutathione(GSH)supplementation in maturation and adaptation media on oocyte development,embryo quality,and oocyte viability after vitrification.Methods:The GSH concentrations were classified into four groups(0,0.5,1.0,and 1.5 mM)which were added to the maturation medium.The maturation process was conducted in vitro for 24 h.Following maturation,oocytes were fertilized with Bali bull semen for 5-6 h and then cultured for 48 h.The morphological quality of ocytes matured with GSH addition and the vitrification method used was evaluated.Parameters assessed included maturation rate,fertilization rate,embryo development,post-vitrification oocyte morphology,and quality of post-vitrification oocytes with GSH added to the adaptation medium.Results:The addition of GSH to the maturation medium significantly improved oocyte quality and embryo development(P<0.05).Specifically,adding 1.5 mM GSH increased the percentage of oocytes reaching metaphase栻from 57.6%without GSH oocytes to 79.0%with 1.5 mM GSH,two-pronuclei fertilization from 47.0%to 72.7%,embryo development from 37.1%to 57.2%,morula formation from 14.6%to 33.7%,and blastocyst formation from 8.1%to 23.8%.Additionally,the survival rate of oocytes post-vitrification increased to 75%with GSH supplementation.Conclusions:The addition of 0.5-1.5 mM of GSH to the maturation and adaptation media significantly enhanced the metaphase栻stage,fertilization rates,cleavage rates,and the survival of oocytes after vitrification.Among the concentrations of 1.5 mM was the most effective in increasing oocyte development and maintaining oocytes viability post-vitrification.展开更多
Oocyte cryopreservation is an essential procedure in assisted reproductive technologies,aimed at preserving fertility,particularly for women undergoing IVF treatment or at risk of ovarian damage due to radiation,chemo...Oocyte cryopreservation is an essential procedure in assisted reproductive technologies,aimed at preserving fertility,particularly for women undergoing IVF treatment or at risk of ovarian damage due to radiation,chemotherapy,or surgery.Despite its growing use,the survival and fertilization rates of cryopreserved oocytes remain suboptimal,largely due to cryo-induced oxidative stress.The generation of Reactive Oxygen Species(ROS)during freezing and thawing causes considerable damage to key cellular components,including proteins,lipids,DNA,and mitochondria.This oxidative stress compromises oocyte quality and reduces developmental potential.To address these challenges,the use of additives-especially antioxidants-has shown significant promise in mitigating oxidative damage.Enzymatic antioxidants such as Superoxide Dismutase(SOD)and Catalase(CAT),along with non-enzymatic antioxidants like glutathione,melatonin,and resveratrol,have demonstrated the ability to neutralize ROS and improve oocyte viability and developmental outcomes.Recent studies highlight the potential of Mitoquinone(MitoQ),a mitochondria-targeted antioxidant,to effectively counteract mitochondrial ROS and enhance cellular defense mechanisms during cryopreservation.This review explores the cellular mechanisms of cryodamage,the role of oxidative stress in oocyte cryopreservation,and the potential of various antioxidant strategies to enhance oocyte survival and function.Developing effective antioxidant supplementation approaches may significantly improve the outcomes of cryopreservation in reproductive medicine.展开更多
This study aimed to optimization of the in vitro fertilization system in Cỏ goat oocytes to achieve the maximum possible blastocyst development rate. In Experiment 1, we assessed the effects of IVF media on the in vit...This study aimed to optimization of the in vitro fertilization system in Cỏ goat oocytes to achieve the maximum possible blastocyst development rate. In Experiment 1, we assessed the effects of IVF media on the in vitro fertilization of Cỏ goat oocytes. There was no significant difference in the cleavage, blastocyst, or hatching rates between TALP-Fert and BO-IVF media. Experiment 2 was performed to assess the concentration of sperm in the in vitro fertilization of Cỏ goat oocytes. The matured Cỏ goat oocytes were fertilized in BO-IVF for four sperm concentrations: 5 × 105, 1 × 106, 2 × 106 and 3 × 106 sperm/ml. The blastocyst rate of 2 × 106 sperm/ml and 3 × 106 sperm/ml groups was higher than that of 5 × 105 sperm/ml and 1 × 106 sperm/ml groups (P Experiment 3 was performed to assess the IVF duration on the in vitro fertilization of Cỏ goat oocytes. The matured Cỏ goat oocytes were fertilized in BO-IVF with sperm concentration of 3 × 106 sperm/ml for 18, 20, 22 and 24 h. The cleavage, blastocyst, and hatching blastocyst rates of 18 h group were lower than those of 20, 22 and 24 h groups (P 0.05). In conclusion, the matured Cỏ goat oocytes were fertilized in BO-IVF with sperm concentration of 3 × 106 sperm/ml for 20 hours, which is suitable for the in vitro Cỏ goat embryo production.展开更多
[Objective] The research aimed to enhance culture efficiencies of oocyte and embryo of goat in vitro and to explore serum-free culture system in vitro.[Method] At present,the conventional solutions of oocyte maturatio...[Objective] The research aimed to enhance culture efficiencies of oocyte and embryo of goat in vitro and to explore serum-free culture system in vitro.[Method] At present,the conventional solutions of oocyte maturation and embryo development in vitro were always added into 1% ITS(Insulin-transferrin-selenium) or using 1% ITS to replace FBS in 2 kinds culture solutions for conducting in vitro cultures of goat oocyte and parthenogenetic embryo.The influences of ITS on their developments were detected.[Result] ITS in maturation liquid of oocytes could not increase oocytes maturation rate but significantly increased blastocyst rate (58.06% vs. 48.19%)of parthenogenetic embryo.If FBS in maturation liquid of oocytes was replaced by ITS, the maturation rate, cleavage rate and blastocyst rate were basically unchanged.Adding ITS into embryo medium could increase blastocyst rate (68.30% vs. 56.82%)of parthenogenetic embryo of goat.If FBS in embryo medium was replaced by ITS,the cleavage rate didn’t change basically,while the blastocyst rate in ITS was obviously lower than that in FBS group(42.33% vs.56.82%).[Conclusion] ITS could promote maturation of oocyte in vitro and early embryonic development, in addition,ITS could replace serum in maturation medium of oocyte as serum-free culture system for conducting relevant researches.展开更多
Mice preantral follicles were cultured in vitro for 12 days to achieve metaphase Ⅱ （M Ⅱ ） oocytes. Oocyte growth differentiation factor-9 （GDF-9） gene expression was measured during different growth stages to ex...Mice preantral follicles were cultured in vitro for 12 days to achieve metaphase Ⅱ （M Ⅱ ） oocytes. Oocyte growth differentiation factor-9 （GDF-9） gene expression was measured during different growth stages to explore the relationship between oocyte maturation and GDF-9 gene expression. Preantral follicles of lO-day old mice were isolated from the ovaries and were cultured for 12 days. Oocytes from day 2 （D2）, D4, D6, D8, DIO, D12 cultured in vitro were named the in vitro group and oocytes of day 12 （D12）, D14, D16, D18, D20, D22 grown in vivo were named the in vivo group. Follicle survival, antrum formation and maturation rate were 89.5%, 51.8% and 56.6% respectively in follicles cultured in vitro. After RT-PCR and agarose gel electrophoresis, relative mRNA abundance of GDF-9 was measured in each group of oocytes. At day 8 - 12, the GDF-9 gene expression level of oocytes in vitro was significantly lower than that in vivo （P 〈 0.05）. We conclude that M Ⅱ oocytes can be obtained from in vitro culture of preantral follicles. The GDF- 9 gene expression of oocytes varies at different growth stages in vivo. The low expression of GDF-9 in oocytes cuhured in vitro may be the cause of their low developmental capacity.展开更多
[Objective] The study aimed to provide references for the time of oocyte maturation in vitro and enucleation in the course of sheep nuclear transfer(NT).[Method] Compared the effects of different maturation time of oo...[Objective] The study aimed to provide references for the time of oocyte maturation in vitro and enucleation in the course of sheep nuclear transfer(NT).[Method] Compared the effects of different maturation time of oocytes on enucleation efficiency and reconstructed embryo development by means of blind enucleation and fluorescence microscopy.[Result] Treatment of IVM(in vitro maturation)19-21 h was significantly higher than IVM 16-18 h treatment in oocyte maturation rate(P<0.05)and was significantly higher than IVM 22-24 h treatment in enucleation rate(P<0.05).Three treatments had no significant difference in cleavage rate and blastocyst rate(P>0.05),but IVM 19-21 h treatment was significantly higher than the other 2 treatments in average cell number of blastocysts(P<0.05).[Conclusion] The appropriate in vitro maturation time of oocytes was 19-21 h for sheep nuclear transfer,which could significantly improve the quality of blastocysts according to the cell number per blastocyst(P<0.05).展开更多
Partial cDNA sequence of rabbit BMP15 was cloned by RT-PCR from rabbit ovaries, showing a similarity of 83%-90% with the BMP15 nucleotide sequences in humans, mice, ovine, sheep, cows and pigs. The expression of BMP15...Partial cDNA sequence of rabbit BMP15 was cloned by RT-PCR from rabbit ovaries, showing a similarity of 83%-90% with the BMP15 nucleotide sequences in humans, mice, ovine, sheep, cows and pigs. The expression of BMP15 in rabbit cumulus-oocyte complexs during oocytes in vitro maturation （IVM） was measured by fluorescent quantitative RT-PCR method. BMP 15 was expressed at low levels in immature oocytes and increased to the highest level at 16h of IVM, which coincides with the time of cumulus cell expansion, then declined slowly under IVM cultivation. The expression pattern of BMP 15 suggested that it might be important in cumulus expansion in rabbits.展开更多
To solve the problem of immune incompatibility, nuclear transplantation has been envisaged as a means to produce cells or tissues for human autologous transplantation. Here we have derived embryonic stem cells by the ...To solve the problem of immune incompatibility, nuclear transplantation has been envisaged as a means to produce cells or tissues for human autologous transplantation. Here we have derived embryonic stem cells by the transfer of human somatic nuclei into rabbit oocytes. The number of blastocysts that developed from the fused nuclear transfer was comparable among nuclear donors at ages of 5, 42, 52 and 60 years, and nuclear transfer (NT) embryonic stem cells (ntES cells) were subsequently derived from each of the four age groups. These results suggest that human somatic nuclei can form ntES cells independent of the age of the donor. The derived ntES cells are human based on karyotype, isogenicity, in situ hybridization, PCR and immunocytochemistry with probes that distinguish between the various species. The ntES cells maintain the capability of sustained growth in an undifferentiated state, and form embryoid bodies, which, on further induction, give rise to cell types such as neuron and muscle, as well as mixed cell populations that express markers representative of all three germ layers. Thus, ntES cells derived from human somatic cells by NT to rabbit eggs retain phenotypes similar to those of conventional human ES cells, including the ability to undergo multilineage cellular differentiation.展开更多
[Objective] The aim was to optimize Yanbian cow oocytes mature in vitro and cleavage system after nuclear transfer based on uniform design. [Method] Oocytes were recovered by aspiration method, and oocytes were mature...[Objective] The aim was to optimize Yanbian cow oocytes mature in vitro and cleavage system after nuclear transfer based on uniform design. [Method] Oocytes were recovered by aspiration method, and oocytes were matured in vitro （IVM） with different conditions, and then carried out nucleus transfer, fusion, activation and in vitro culture （IVC） of embryo. Effects of ovary storage temperature, maturation time and follicular diameter size on in vitro maturation and cleavage rates of cow oocytes were compared. [ Result] The best conditions of IVM of Yanbian cow oocytes was that： the oocytes of 8 mm diameter were matured in vitro for 24 hours when the ovaries were stored at 26℃ or 31 ℃. The best cleave conditions after nucleus transfer of oocytes was that： the oocytes of 6 mm or 8 mm diameter were cultured in vitro for 24 hours when the ovaries were stored at 26℃. [ Conclusion] The result has some reference to Yanbian cow and other cow breeding and population expanding propagation.展开更多
[ Objective] The research aimed to explore the manufacturing methods of scanning electron microscope （SEM） and transmission electron microscopy （TEM） for oocyte and provide technical support for related research. ...[ Objective] The research aimed to explore the manufacturing methods of scanning electron microscope （SEM） and transmission electron microscopy （TEM） for oocyte and provide technical support for related research. [ Method] Based on GV-and MII-stage oocytes, samples of SEM and TEM were prepared respectively, then ultrastructure changes were observed. [ Result] The results showed that the method needed few samples, keep intact cell morphology and can see clear ultrastructure. [Conclusion] The method is suitable for ultrastructural observation of oocyte.展开更多
[Objective] The aim of this study was to increase the viability of sheep oocytes in vitro by using phosphodiesterase type 3（PDE 3） inhibitor milrinone combined with brilliant cresyl blue（BCB） staining.[Method] The...[Objective] The aim of this study was to increase the viability of sheep oocytes in vitro by using phosphodiesterase type 3（PDE 3） inhibitor milrinone combined with brilliant cresyl blue（BCB） staining.[Method] The differences between BCB tested and morphologically selected oocytes,as well as the effect of them on embryo development were compared;and then suitable inhibitive time of milrinone to sheep oocytes in vitro was studied and used in BCB-oocytes for in vitro embryo production（IVEP）.[Result] The BCB＋ oocytes percentage in A-and B-level sheep oocytes was 64.42%,which was extremely significantly higher than that in C-level（17.0%）.The maturing rate,cleavage rate and blastocyst rate of BCB＋ oocytes（86.16%,85.29% and 34.40%） of was significantly higher than those of BCB-oocytes（50.94%,36.19% and 6.73%）.The best time for PDE 3 inhibitor delaying the sheep oocyte mature in vitro was 6 h.In addition,the rate of embryo development in vitro could be significantly increased by inhibiting the BCB-oocytes for 6 h with Milrinone.[Conclusion] The study will provide reference for improving the efficiency of sheep oocytes culture in vitro.展开更多
[Objective] This study aimed to improve the in vitro maturation quality of denuded porcine oocytes and provide scientific basis for establishing a stable and efficient denuded oocyte culture system. [Method] The first...[Objective] This study aimed to improve the in vitro maturation quality of denuded porcine oocytes and provide scientific basis for establishing a stable and efficient denuded oocyte culture system. [Method] The first polar body extrusion rate, oocyte glutathione （GSH） content, positive rate of brilliant cresyl blue （BCB） staining and development potential of activated oocytes or fertilized oocytes were employed as main indicators to investigate the effects of follicular mural granulosa cell （MGC） coculture on cytoplasmic maturation of cumulus cell-removal oocytes （Denuded Oocyte, DO）. [Result] According to in vitro maturation results, compared with DO group, the first polar body extrusion rate of porcine oocytes in DO＋MGC group was not significantly different, but the nuclear maturation process was improved and was more similar to that in COC （cumulus-oocyte complex） group. Detection of GSH content in mature oocytes showed that there was no significant difference between DO＋ MGC group （optical density of 1 053.67） and COC group （optical density of 1 426.00） or between DO＋MGC group and COC＋GC group （optical density of 1 541.00）, however, GSH content in mature oocytes of DO group （optical density of 724.67） was significantly lower than that of COC group and COC＋GC group （P0.05）. Detection of glucose-6-phosphate dehydrogenase （G6PDH） activity showed that there was no significant difference in BCB positive oocyte rate between DO ＋MGC group （88.26% ） and COC group （92.75%） or between DO＋MGC group and DO group （82.86% ）, however, BCB positive oocyte rate of DO group was significantly lower than that of COC group （P0.05）. Furthermore, the cleavage rate and blastocyst rate of activated mature oocytes derived from DO ＋MGC group （94.98% and 43.67% , respectively） were significantly higher than those from DO group （52.54% and 8.97%, respectively） （P0.05）, and were not significantly different compared with those from COC group （97.11% and 38.30%, respectively）. In addition, the cleavage rate of fertilized oocytes derived from DO＋MGC group （72.65%） showed no significant difference compared with that from DO group （63.59%）, but the blastocyst rate of DO＋MGC group was significantly higher than that of DO group （9.88%） （P0.05）. [Conclusion] MGC coculture can significantly improve the in vitro cytoplasmic maturation quality of denuded porcine oocytes, thereby enhancing the subsequent developmental potential.展开更多
[Objective] This study aimed to investigate the appropriate concentrations of follicle-stimulating hormone（FSH）, luteotropic hormone（LH） and estrodiol（E2） during in vitro maturation of Tan sheep oocytes. [Method...[Objective] This study aimed to investigate the appropriate concentrations of follicle-stimulating hormone（FSH）, luteotropic hormone（LH） and estrodiol（E2） during in vitro maturation of Tan sheep oocytes. [Method] Tan sheep oocytes were divided into five groups for in vitro maturation culture： control group, FSH group（10,50, 100, 200 and 300 μg/ml FSH, respectively）, LH group（5, 10, 20, 50 and 100μg/ml LH, respectively）, E2group（5, 10, 25, 50 and 100 μg/ml E2, respectively）, and FSH ＋ LH group（100 μg/ml FSH ＋ 20 μg/ml LH）. The releasing rate of first polar bodies was analyzed. [Result] The maturation rate of Tan sheep oocytes in 100 μg/ml FSH ＋ 20 μg/ml LH group reached the highest（64.64%）, which was significantly higher than that in other four groups（P〈0.05）; among different FSH concentrations,100 μg/ml FSH was superior to other four concentrations and the control group, exhibiting significant differences（P〈0.05）; among different LH concentrations, 20 μg/ml LH was superior to other four concentrations and the control group, exhibiting significant differences（P〈0.05）; among different E2 concentrations, 50 μg/ml E2 was superior to other four concentrations and the control group, exhibiting significant differences（P〈0.05）. [Conclusion] Under the experimental conditions, 100 μg/ml FSH ＋20 μg/ml LH was the most appropriate hormone combination for in vitro maturation of Tan sheep oocytes.展开更多
Comparisons of activation rates and fertilization rates were made among oocytes at different ages. Results showed that oocytes at different ages had different activation and fertilization rates when stimulated by sper...Comparisons of activation rates and fertilization rates were made among oocytes at different ages. Results showed that oocytes at different ages had different activation and fertilization rates when stimulated by sperm or ethanol. Oocytes at 15～24 h after the injection of hCG were readily activated by 8% ethanol. The activation rate of oocytes increased with the age of oocytes, up to the highest average of 81.6%, but decreased after 20 h posthCG. Oocytes at 20 h posthCG exhibited the highest immediate cleavage rate(48.0%) after being stimulated by ethanol. On the other hand, 13～15 h oocytes exhibited higher fertilization rates, and the older oocytes were more difficult to be fertilized by sperm in vitro. These suggest that oocytes can be activated in different ways; the mechanism of fertilization might be different from that of activation; and in vitro fertilization is more dependent on oocyte age.展开更多
AIM: Hepatitis B is a worldwide public health problem. To explore the feasibility of hepatitis B virus (HBV) vertical transmission via oocytes, the presence and integration of HBV DNA in mouse oocytes were studied. ME...AIM: Hepatitis B is a worldwide public health problem. To explore the feasibility of hepatitis B virus (HBV) vertical transmission via oocytes, the presence and integration of HBV DNA in mouse oocytes were studied. METHODS: Genomic DNA was isolated and metaphases were prepared, respectively from mouse oocytes cocultured with pBR322-HBV DNA plasmids. PCR, Southern blot, dot hybridization and fluorescence in situ hybridization (FISH) were performed to explore the existence and integration of HBV DNA in oocytes.RESULTS: PCR detected positive bands in the tested samples, and then Southern blot revealed clear hybridization signals in PCR products. Final washing solutions were collected for dot hybridization and no signal for HBV DNA was observed, which excluded the possibility that contamination of washing solutions gave rise to positive results of PCR and Southern blot. FISH demonstrated that 36 of 1 000 metaphases presented positive signals. CONCLUSION: HBV DNA sequences are able to pass through the zona and oolemma to enter into oocytes and tointegrate into their chromosomes. HBV DNA sequences might be brought into embryo via oocytes as vectors when they are fertilized with normal spermatozoa.展开更多
One of the main causes of pregnancy failure and fetus abortion is oocyte aneuploidy,which is increased with maternal aging.Numerous possible causes of oocyte aneuploidy in aged women have been proposed,including cross...One of the main causes of pregnancy failure and fetus abortion is oocyte aneuploidy,which is increased with maternal aging.Numerous possible causes of oocyte aneuploidy in aged women have been proposed,including cross-over formation defect,cohesin loss,spindle deformation,spindle assembly checkpoint malfunction,microtubule-kinetochore attachment failure,kinetochore mis-orientation,mitochondria dysfunction-induced increases in reactive oxygen species,protein over-acetylation,and DNA damage.However,it still needs to be answered if these aneuploidization factors have inherent relations,and how to prevent chromosome aneuploidy in aged oocytes.Epidemiologically,oocyte aneuploidy has been found to be weakly associated with higher homocysteine concentrations,obesity,ionizing radiation and even seasonality.In this review,we summarize the research progress and present an integrated view of oocyte aneuploidization.展开更多
Oocyte quality has long been considered as a main limiting factor for in vitro fertilization （IVF）. In the past decade, extensive observations demonstrated that the mitochondrion plays a vital role in the oocyte cyt...Oocyte quality has long been considered as a main limiting factor for in vitro fertilization （IVF）. In the past decade, extensive observations demonstrated that the mitochondrion plays a vital role in the oocyte cytoplasm, for it can provide adenosine triphosphate （ATP） for fertilization and preimplantation embryo development and also act as stores of intracellular calcium and proapoptotic factors. During the oocyte maturation, mitochondria are characterized by distinct changes of their distribution pattern from being homogeneous to heterogeneous, which is correlated with the cumulus apoptosis. Oocyte quality decreases with the increasing maternal age. Recent studies have shown that low quality oocytes have some age-related dysfunctions, which include the decrease in mitochondrial membrane potential, increase of mitochondrial DNA （mtDNA） damages, chromosomal aneuploidies, the incidence of apoptosis, and changes in mitochoncLrial gene expression. All these dysfunctions may cause a high level of de- velopmental retardation and arrest of preimplantation embryos. It has been suggested that these mitochondrial changes may arise from excessive reactive oxygen species （ROS） that is closely associated with the oxidative energy production or calcium overload, which may trigger permeability transition pore opening and subsequent apoptosis. Therefore, mitochondria can be seen as signs for oocyte quality evaluation, and it is possible that the oocyte quality can be improved by enhancing the physical function of mitochondria. Here we reviewed recent advances in mitochondrial functions on oocytes.展开更多
Selecting oocytes that are most likely to develop is crucial for in vitro fertilization and animal cloning. Brilliant cresyl blue （BCB） staining has been used for oocyte selection in large animals, but its wider uti...Selecting oocytes that are most likely to develop is crucial for in vitro fertilization and animal cloning. Brilliant cresyl blue （BCB） staining has been used for oocyte selection in large animals, but its wider utility needs further evaluation. Mouse oocytes were divided into those stained （BCB＋） and those unstained （BCB-） according to their ooplasm BCB coloration. Chromatin configurations, cumulus cell apoptosis, cytoplasmic maturity and developmental competence were compared between the BCB＋ and BCB- oocytes. The effects of oocyte diameter, sexual maturity and gonadotropin stimulation on the competence of BCB＋ oocytes were also analyzed. In the large- and medium-size groups, BCB＋ oocytes were larger and showed more surrounded nucleoli （SN） chromatin configurations and higher frequencies of early atresia, and they also gained better cytoplasmic maturity （determined as the intracellular GSH level and pattern of mitochondrial distribution） and higher developmental potential after in vitro maturation （IVM） than the BCB-oocytes. Adult mice produced more BCB＋ oocytes with higher competence than the prepubertal mice when not primed with PMSG. PMSG priming increased both proportion and developmental potency of BCB＋ oocytes. The BCB＋ oocytes in the large-size group showed more SN chromatin configurations, better cytoplasmic maturity and higher developmental potential than their counterparts in the medium-size group. It is concluded that BCB staining can be used as an efficient method for oocyte selection, but that the competence of the BCB＋ oocytes may vary with oocyte diameter, animal sexual maturity and gonadotropin stimulation. Taken together, the series of criteria described here would allow for better choices in selecting oocytes for better development.展开更多
文摘Rationale:This case report describes a couple with recurrent fertilization failure despite undergoing multiple cycles of intracytoplasmic sperm injection(ICSI).The principal clinical concern was suspected oocyte activation deficiency(OAD),in which fertilization is impeded due to the oocyte’s inability to initiate embryogenesis,commonly attributed to inadequate intracellular calcium(Ca^(2+))release following sperm injection.Patient concerns:The couple repeatedly experienced complete or near-complete fertilization failure in previous ICSI cycles,raising suspicion of an underlying oocyte activation defect.Diagnosis:Based on the repeated absence of fertilization post-ICSI and clinical history,a diagnosis of suspected OAD leading to recurrent ICSI fertilization failure was considered.Interventions:Artificial oocyte activation(AOA)using the calcium ionophore A23187 was performed.After ICSI,unfertilized oocytes were exposed to the ionophore to induce Ca^(2+)influx,simulating physiological calcium oscillations essential for oocyte activation.The efficacy of intervention was evaluated through subsequent embryonic development,morphological grading,and chromosomal integrity.Outcomes:Following AOA treatment,successful oocyte activation occurred,resulting in the formation of high-grade embryos with normal developmental progression.Chromosomal analysis revealed no detectable abnormalities,indicating genomic stability.Lessons:Calcium ionophore–mediated AOA may serve as an effective adjunct in cases of recurrent ICSI failure attributed to OAD.This case highlights the importance of individualized therapeutic strategies in assisted reproduction;however,further research is needed to refine protocols,validate broader clinical efficacy,and assess long-term safety,including potential epigenetic risks.
基金National Natural Science Foundation of China(Grant Nos.32070838 and 82301874)Open Fund of State Key Laboratory of Reproductive Medicine,Nanjing Medical University(Grant No.SKLRM K202102)。
文摘Meiotic resumption in mammalian oocytes involves nuclear and organelle structural changes,notably the chromatin configuration transition from a non-surrounding nucleolus(NSN)to surrounding nucleolus(SN)in germinal vesicle oocytes.In the current study,we found that nuclear speckles(NSs),a subnuclear structure mainly composed of serine-arginine(SR)proteins,changed from a diffuse spotted distribution in mouse NSN oocytes to an aggregated pattern in SN oocytes.We also found that the SR protein-specific kinase 1(SRPK1),an enzyme that phosphorylates SR proteins,co-localized with NSs at the SN stage,and that NSN oocytes failed to transition to SN oocytes after the inhibition of SRPK1 activity.Furthermore,the typical structure of the chromatin ring around the nucleolus in SN oocytes collapsed after treatment with an SRPK1 inhibitor.Mechanistically,phosphorylated SR proteins were found to be related to chromatin as shown by a salt extraction experiment,and in situ DNaseⅠassay showed that the accessibility of chromatin was enhanced in SN oocytes when SRPK1 was inhibited,accompanied by a decreased repressive modification on histone and the abnormal recurrence of a transcriptional signal.In conclusion,our results indicated that SRPK1-regulated phosphorylation of SR proteins was involved in the NSN-SN transition and played an important role in maintaining the condensed nucleus of SN oocytes via interacting with chromatin.
基金This study was financially supported by Universitas Hasanuddin through Penelitian Fundamental Kolaboratif(PFK)(letter of appointment number:00323/UN4.22/PT.0103/2023).
文摘Objective:To evaluate the effect of glutathione(GSH)supplementation in maturation and adaptation media on oocyte development,embryo quality,and oocyte viability after vitrification.Methods:The GSH concentrations were classified into four groups(0,0.5,1.0,and 1.5 mM)which were added to the maturation medium.The maturation process was conducted in vitro for 24 h.Following maturation,oocytes were fertilized with Bali bull semen for 5-6 h and then cultured for 48 h.The morphological quality of ocytes matured with GSH addition and the vitrification method used was evaluated.Parameters assessed included maturation rate,fertilization rate,embryo development,post-vitrification oocyte morphology,and quality of post-vitrification oocytes with GSH added to the adaptation medium.Results:The addition of GSH to the maturation medium significantly improved oocyte quality and embryo development(P<0.05).Specifically,adding 1.5 mM GSH increased the percentage of oocytes reaching metaphase栻from 57.6%without GSH oocytes to 79.0%with 1.5 mM GSH,two-pronuclei fertilization from 47.0%to 72.7%,embryo development from 37.1%to 57.2%,morula formation from 14.6%to 33.7%,and blastocyst formation from 8.1%to 23.8%.Additionally,the survival rate of oocytes post-vitrification increased to 75%with GSH supplementation.Conclusions:The addition of 0.5-1.5 mM of GSH to the maturation and adaptation media significantly enhanced the metaphase栻stage,fertilization rates,cleavage rates,and the survival of oocytes after vitrification.Among the concentrations of 1.5 mM was the most effective in increasing oocyte development and maintaining oocytes viability post-vitrification.
基金Anhui Province Clinical Medical Research Translation Special Program(No.2204295107020002).
文摘Oocyte cryopreservation is an essential procedure in assisted reproductive technologies,aimed at preserving fertility,particularly for women undergoing IVF treatment or at risk of ovarian damage due to radiation,chemotherapy,or surgery.Despite its growing use,the survival and fertilization rates of cryopreserved oocytes remain suboptimal,largely due to cryo-induced oxidative stress.The generation of Reactive Oxygen Species(ROS)during freezing and thawing causes considerable damage to key cellular components,including proteins,lipids,DNA,and mitochondria.This oxidative stress compromises oocyte quality and reduces developmental potential.To address these challenges,the use of additives-especially antioxidants-has shown significant promise in mitigating oxidative damage.Enzymatic antioxidants such as Superoxide Dismutase(SOD)and Catalase(CAT),along with non-enzymatic antioxidants like glutathione,melatonin,and resveratrol,have demonstrated the ability to neutralize ROS and improve oocyte viability and developmental outcomes.Recent studies highlight the potential of Mitoquinone(MitoQ),a mitochondria-targeted antioxidant,to effectively counteract mitochondrial ROS and enhance cellular defense mechanisms during cryopreservation.This review explores the cellular mechanisms of cryodamage,the role of oxidative stress in oocyte cryopreservation,and the potential of various antioxidant strategies to enhance oocyte survival and function.Developing effective antioxidant supplementation approaches may significantly improve the outcomes of cryopreservation in reproductive medicine.
文摘This study aimed to optimization of the in vitro fertilization system in Cỏ goat oocytes to achieve the maximum possible blastocyst development rate. In Experiment 1, we assessed the effects of IVF media on the in vitro fertilization of Cỏ goat oocytes. There was no significant difference in the cleavage, blastocyst, or hatching rates between TALP-Fert and BO-IVF media. Experiment 2 was performed to assess the concentration of sperm in the in vitro fertilization of Cỏ goat oocytes. The matured Cỏ goat oocytes were fertilized in BO-IVF for four sperm concentrations: 5 × 105, 1 × 106, 2 × 106 and 3 × 106 sperm/ml. The blastocyst rate of 2 × 106 sperm/ml and 3 × 106 sperm/ml groups was higher than that of 5 × 105 sperm/ml and 1 × 106 sperm/ml groups (P Experiment 3 was performed to assess the IVF duration on the in vitro fertilization of Cỏ goat oocytes. The matured Cỏ goat oocytes were fertilized in BO-IVF with sperm concentration of 3 × 106 sperm/ml for 18, 20, 22 and 24 h. The cleavage, blastocyst, and hatching blastocyst rates of 18 h group were lower than those of 20, 22 and 24 h groups (P 0.05). In conclusion, the matured Cỏ goat oocytes were fertilized in BO-IVF with sperm concentration of 3 × 106 sperm/ml for 20 hours, which is suitable for the in vitro Cỏ goat embryo production.
文摘[Objective] The research aimed to enhance culture efficiencies of oocyte and embryo of goat in vitro and to explore serum-free culture system in vitro.[Method] At present,the conventional solutions of oocyte maturation and embryo development in vitro were always added into 1% ITS(Insulin-transferrin-selenium) or using 1% ITS to replace FBS in 2 kinds culture solutions for conducting in vitro cultures of goat oocyte and parthenogenetic embryo.The influences of ITS on their developments were detected.[Result] ITS in maturation liquid of oocytes could not increase oocytes maturation rate but significantly increased blastocyst rate (58.06% vs. 48.19%)of parthenogenetic embryo.If FBS in maturation liquid of oocytes was replaced by ITS, the maturation rate, cleavage rate and blastocyst rate were basically unchanged.Adding ITS into embryo medium could increase blastocyst rate (68.30% vs. 56.82%)of parthenogenetic embryo of goat.If FBS in embryo medium was replaced by ITS,the cleavage rate didn’t change basically,while the blastocyst rate in ITS was obviously lower than that in FBS group(42.33% vs.56.82%).[Conclusion] ITS could promote maturation of oocyte in vitro and early embryonic development, in addition,ITS could replace serum in maturation medium of oocyte as serum-free culture system for conducting relevant researches.
文摘Mice preantral follicles were cultured in vitro for 12 days to achieve metaphase Ⅱ （M Ⅱ ） oocytes. Oocyte growth differentiation factor-9 （GDF-9） gene expression was measured during different growth stages to explore the relationship between oocyte maturation and GDF-9 gene expression. Preantral follicles of lO-day old mice were isolated from the ovaries and were cultured for 12 days. Oocytes from day 2 （D2）, D4, D6, D8, DIO, D12 cultured in vitro were named the in vitro group and oocytes of day 12 （D12）, D14, D16, D18, D20, D22 grown in vivo were named the in vivo group. Follicle survival, antrum formation and maturation rate were 89.5%, 51.8% and 56.6% respectively in follicles cultured in vitro. After RT-PCR and agarose gel electrophoresis, relative mRNA abundance of GDF-9 was measured in each group of oocytes. At day 8 - 12, the GDF-9 gene expression level of oocytes in vitro was significantly lower than that in vivo （P 〈 0.05）. We conclude that M Ⅱ oocytes can be obtained from in vitro culture of preantral follicles. The GDF- 9 gene expression of oocytes varies at different growth stages in vivo. The low expression of GDF-9 in oocytes cuhured in vitro may be the cause of their low developmental capacity.
基金Supported by School Program of Henan Institute of Science and Technology(20060516)~~
文摘[Objective] The study aimed to provide references for the time of oocyte maturation in vitro and enucleation in the course of sheep nuclear transfer(NT).[Method] Compared the effects of different maturation time of oocytes on enucleation efficiency and reconstructed embryo development by means of blind enucleation and fluorescence microscopy.[Result] Treatment of IVM(in vitro maturation)19-21 h was significantly higher than IVM 16-18 h treatment in oocyte maturation rate(P<0.05)and was significantly higher than IVM 22-24 h treatment in enucleation rate(P<0.05).Three treatments had no significant difference in cleavage rate and blastocyst rate(P>0.05),but IVM 19-21 h treatment was significantly higher than the other 2 treatments in average cell number of blastocysts(P<0.05).[Conclusion] The appropriate in vitro maturation time of oocytes was 19-21 h for sheep nuclear transfer,which could significantly improve the quality of blastocysts according to the cell number per blastocyst(P<0.05).
文摘Partial cDNA sequence of rabbit BMP15 was cloned by RT-PCR from rabbit ovaries, showing a similarity of 83%-90% with the BMP15 nucleotide sequences in humans, mice, ovine, sheep, cows and pigs. The expression of BMP15 in rabbit cumulus-oocyte complexs during oocytes in vitro maturation （IVM） was measured by fluorescent quantitative RT-PCR method. BMP 15 was expressed at low levels in immature oocytes and increased to the highest level at 16h of IVM, which coincides with the time of cumulus cell expansion, then declined slowly under IVM cultivation. The expression pattern of BMP 15 suggested that it might be important in cumulus expansion in rabbits.
基金supported by grants from the Major State Basic Research Development Program of China(No.001CB5099)the National High Technology Research and Development Program of China(No.2001AA216121)+3 种基金National Natural Science Foundation of China(No.30040003)Projects of Shanghai Science&Technology Development Foundation(No.99DJ14002,00DJ14033,01DJ14003)the Chinese Academy of Sciences(No.KSCX-2-3-08)Shanghai Municipal Education Commission and by Shanghai Second Medical University
文摘To solve the problem of immune incompatibility, nuclear transplantation has been envisaged as a means to produce cells or tissues for human autologous transplantation. Here we have derived embryonic stem cells by the transfer of human somatic nuclei into rabbit oocytes. The number of blastocysts that developed from the fused nuclear transfer was comparable among nuclear donors at ages of 5, 42, 52 and 60 years, and nuclear transfer (NT) embryonic stem cells (ntES cells) were subsequently derived from each of the four age groups. These results suggest that human somatic nuclei can form ntES cells independent of the age of the donor. The derived ntES cells are human based on karyotype, isogenicity, in situ hybridization, PCR and immunocytochemistry with probes that distinguish between the various species. The ntES cells maintain the capability of sustained growth in an undifferentiated state, and form embryoid bodies, which, on further induction, give rise to cell types such as neuron and muscle, as well as mixed cell populations that express markers representative of all three germ layers. Thus, ntES cells derived from human somatic cells by NT to rabbit eggs retain phenotypes similar to those of conventional human ES cells, including the ability to undergo multilineage cellular differentiation.
文摘[Objective] The aim was to optimize Yanbian cow oocytes mature in vitro and cleavage system after nuclear transfer based on uniform design. [Method] Oocytes were recovered by aspiration method, and oocytes were matured in vitro （IVM） with different conditions, and then carried out nucleus transfer, fusion, activation and in vitro culture （IVC） of embryo. Effects of ovary storage temperature, maturation time and follicular diameter size on in vitro maturation and cleavage rates of cow oocytes were compared. [ Result] The best conditions of IVM of Yanbian cow oocytes was that： the oocytes of 8 mm diameter were matured in vitro for 24 hours when the ovaries were stored at 26℃ or 31 ℃. The best cleave conditions after nucleus transfer of oocytes was that： the oocytes of 6 mm or 8 mm diameter were cultured in vitro for 24 hours when the ovaries were stored at 26℃. [ Conclusion] The result has some reference to Yanbian cow and other cow breeding and population expanding propagation.
基金Supported by Natural Science Foundation of Jiangsu Province(Grant number:BK2008589)Shanghai Committee(Grant num-ber:2003 #14-1)~~
文摘[ Objective] The research aimed to explore the manufacturing methods of scanning electron microscope （SEM） and transmission electron microscopy （TEM） for oocyte and provide technical support for related research. [ Method] Based on GV-and MII-stage oocytes, samples of SEM and TEM were prepared respectively, then ultrastructure changes were observed. [ Result] The results showed that the method needed few samples, keep intact cell morphology and can see clear ultrastructure. [Conclusion] The method is suitable for ultrastructural observation of oocyte.
基金Supported by Natural Science Foundation of Xinjiang AutonomousRegion (200821182 )Science and Technology Research andDevelopment Program of Xinjiang Autonomous Region (200841122)+1 种基金Science and Technology Planning Project of Xinjiang AutonomousRegion (200711104)the National Transgenic Major Program~~
文摘[Objective] The aim of this study was to increase the viability of sheep oocytes in vitro by using phosphodiesterase type 3（PDE 3） inhibitor milrinone combined with brilliant cresyl blue（BCB） staining.[Method] The differences between BCB tested and morphologically selected oocytes,as well as the effect of them on embryo development were compared;and then suitable inhibitive time of milrinone to sheep oocytes in vitro was studied and used in BCB-oocytes for in vitro embryo production（IVEP）.[Result] The BCB＋ oocytes percentage in A-and B-level sheep oocytes was 64.42%,which was extremely significantly higher than that in C-level（17.0%）.The maturing rate,cleavage rate and blastocyst rate of BCB＋ oocytes（86.16%,85.29% and 34.40%） of was significantly higher than those of BCB-oocytes（50.94%,36.19% and 6.73%）.The best time for PDE 3 inhibitor delaying the sheep oocyte mature in vitro was 6 h.In addition,the rate of embryo development in vitro could be significantly increased by inhibiting the BCB-oocytes for 6 h with Milrinone.[Conclusion] The study will provide reference for improving the efficiency of sheep oocytes culture in vitro.
基金Supported by National Natural Science Foundation of China (30871431)Outstanding Youth Fund of Heilongjiang Province (JC200905)~~
文摘[Objective] This study aimed to improve the in vitro maturation quality of denuded porcine oocytes and provide scientific basis for establishing a stable and efficient denuded oocyte culture system. [Method] The first polar body extrusion rate, oocyte glutathione （GSH） content, positive rate of brilliant cresyl blue （BCB） staining and development potential of activated oocytes or fertilized oocytes were employed as main indicators to investigate the effects of follicular mural granulosa cell （MGC） coculture on cytoplasmic maturation of cumulus cell-removal oocytes （Denuded Oocyte, DO）. [Result] According to in vitro maturation results, compared with DO group, the first polar body extrusion rate of porcine oocytes in DO＋MGC group was not significantly different, but the nuclear maturation process was improved and was more similar to that in COC （cumulus-oocyte complex） group. Detection of GSH content in mature oocytes showed that there was no significant difference between DO＋ MGC group （optical density of 1 053.67） and COC group （optical density of 1 426.00） or between DO＋MGC group and COC＋GC group （optical density of 1 541.00）, however, GSH content in mature oocytes of DO group （optical density of 724.67） was significantly lower than that of COC group and COC＋GC group （P0.05）. Detection of glucose-6-phosphate dehydrogenase （G6PDH） activity showed that there was no significant difference in BCB positive oocyte rate between DO ＋MGC group （88.26% ） and COC group （92.75%） or between DO＋MGC group and DO group （82.86% ）, however, BCB positive oocyte rate of DO group was significantly lower than that of COC group （P0.05）. Furthermore, the cleavage rate and blastocyst rate of activated mature oocytes derived from DO ＋MGC group （94.98% and 43.67% , respectively） were significantly higher than those from DO group （52.54% and 8.97%, respectively） （P0.05）, and were not significantly different compared with those from COC group （97.11% and 38.30%, respectively）. In addition, the cleavage rate of fertilized oocytes derived from DO＋MGC group （72.65%） showed no significant difference compared with that from DO group （63.59%）, but the blastocyst rate of DO＋MGC group was significantly higher than that of DO group （9.88%） （P0.05）. [Conclusion] MGC coculture can significantly improve the in vitro cytoplasmic maturation quality of denuded porcine oocytes, thereby enhancing the subsequent developmental potential.
基金Supported by Natural Science Foundation of Ningxia Hui Autonomous Region(NZ12150)~~
文摘[Objective] This study aimed to investigate the appropriate concentrations of follicle-stimulating hormone（FSH）, luteotropic hormone（LH） and estrodiol（E2） during in vitro maturation of Tan sheep oocytes. [Method] Tan sheep oocytes were divided into five groups for in vitro maturation culture： control group, FSH group（10,50, 100, 200 and 300 μg/ml FSH, respectively）, LH group（5, 10, 20, 50 and 100μg/ml LH, respectively）, E2group（5, 10, 25, 50 and 100 μg/ml E2, respectively）, and FSH ＋ LH group（100 μg/ml FSH ＋ 20 μg/ml LH）. The releasing rate of first polar bodies was analyzed. [Result] The maturation rate of Tan sheep oocytes in 100 μg/ml FSH ＋ 20 μg/ml LH group reached the highest（64.64%）, which was significantly higher than that in other four groups（P〈0.05）; among different FSH concentrations,100 μg/ml FSH was superior to other four concentrations and the control group, exhibiting significant differences（P〈0.05）; among different LH concentrations, 20 μg/ml LH was superior to other four concentrations and the control group, exhibiting significant differences（P〈0.05）; among different E2 concentrations, 50 μg/ml E2 was superior to other four concentrations and the control group, exhibiting significant differences（P〈0.05）. [Conclusion] Under the experimental conditions, 100 μg/ml FSH ＋20 μg/ml LH was the most appropriate hormone combination for in vitro maturation of Tan sheep oocytes.
文摘Comparisons of activation rates and fertilization rates were made among oocytes at different ages. Results showed that oocytes at different ages had different activation and fertilization rates when stimulated by sperm or ethanol. Oocytes at 15～24 h after the injection of hCG were readily activated by 8% ethanol. The activation rate of oocytes increased with the age of oocytes, up to the highest average of 81.6%, but decreased after 20 h posthCG. Oocytes at 20 h posthCG exhibited the highest immediate cleavage rate(48.0%) after being stimulated by ethanol. On the other hand, 13～15 h oocytes exhibited higher fertilization rates, and the older oocytes were more difficult to be fertilized by sperm in vitro. These suggest that oocytes can be activated in different ways; the mechanism of fertilization might be different from that of activation; and in vitro fertilization is more dependent on oocyte age.
基金Supported by the National Natural Science Foundation of China,No. 39970374
文摘AIM: Hepatitis B is a worldwide public health problem. To explore the feasibility of hepatitis B virus (HBV) vertical transmission via oocytes, the presence and integration of HBV DNA in mouse oocytes were studied. METHODS: Genomic DNA was isolated and metaphases were prepared, respectively from mouse oocytes cocultured with pBR322-HBV DNA plasmids. PCR, Southern blot, dot hybridization and fluorescence in situ hybridization (FISH) were performed to explore the existence and integration of HBV DNA in oocytes.RESULTS: PCR detected positive bands in the tested samples, and then Southern blot revealed clear hybridization signals in PCR products. Final washing solutions were collected for dot hybridization and no signal for HBV DNA was observed, which excluded the possibility that contamination of washing solutions gave rise to positive results of PCR and Southern blot. FISH demonstrated that 36 of 1 000 metaphases presented positive signals. CONCLUSION: HBV DNA sequences are able to pass through the zona and oolemma to enter into oocytes and tointegrate into their chromosomes. HBV DNA sequences might be brought into embryo via oocytes as vectors when they are fertilized with normal spermatozoa.
基金supported by the National Natural Science Foundation of China(31801245,81671425 and 81971357)Key Research&Development Program of Guangzhou Regenerative Medicine and Health Guangdong Laboratory(2019GZR110104001)
文摘One of the main causes of pregnancy failure and fetus abortion is oocyte aneuploidy,which is increased with maternal aging.Numerous possible causes of oocyte aneuploidy in aged women have been proposed,including cross-over formation defect,cohesin loss,spindle deformation,spindle assembly checkpoint malfunction,microtubule-kinetochore attachment failure,kinetochore mis-orientation,mitochondria dysfunction-induced increases in reactive oxygen species,protein over-acetylation,and DNA damage.However,it still needs to be answered if these aneuploidization factors have inherent relations,and how to prevent chromosome aneuploidy in aged oocytes.Epidemiologically,oocyte aneuploidy has been found to be weakly associated with higher homocysteine concentrations,obesity,ionizing radiation and even seasonality.In this review,we summarize the research progress and present an integrated view of oocyte aneuploidization.
基金supported by the National Natural Science Foundation of China (No. 30772345)the Research Program of the Science and Technology Bureau of Zhejiang Province (No. 2006C33016)+1 种基金the Natural Science Foundation of Zhejiang Province (No. Y204202)the Chinese Medicine Research Program of Zhejiang Province (No. 2007CA071), China
文摘Oocyte quality has long been considered as a main limiting factor for in vitro fertilization （IVF）. In the past decade, extensive observations demonstrated that the mitochondrion plays a vital role in the oocyte cytoplasm, for it can provide adenosine triphosphate （ATP） for fertilization and preimplantation embryo development and also act as stores of intracellular calcium and proapoptotic factors. During the oocyte maturation, mitochondria are characterized by distinct changes of their distribution pattern from being homogeneous to heterogeneous, which is correlated with the cumulus apoptosis. Oocyte quality decreases with the increasing maternal age. Recent studies have shown that low quality oocytes have some age-related dysfunctions, which include the decrease in mitochondrial membrane potential, increase of mitochondrial DNA （mtDNA） damages, chromosomal aneuploidies, the incidence of apoptosis, and changes in mitochoncLrial gene expression. All these dysfunctions may cause a high level of de- velopmental retardation and arrest of preimplantation embryos. It has been suggested that these mitochondrial changes may arise from excessive reactive oxygen species （ROS） that is closely associated with the oxidative energy production or calcium overload, which may trigger permeability transition pore opening and subsequent apoptosis. Therefore, mitochondria can be seen as signs for oocyte quality evaluation, and it is possible that the oocyte quality can be improved by enhancing the physical function of mitochondria. Here we reviewed recent advances in mitochondrial functions on oocytes.
基金Acknowledgments This study was supported by grants from the China National Natural Science Foundation （Nos. 30430530 and 30571337） and from the Momentous Research Project of the China Ministry of Science and Technology （No. 2006CB944003）.
文摘Selecting oocytes that are most likely to develop is crucial for in vitro fertilization and animal cloning. Brilliant cresyl blue （BCB） staining has been used for oocyte selection in large animals, but its wider utility needs further evaluation. Mouse oocytes were divided into those stained （BCB＋） and those unstained （BCB-） according to their ooplasm BCB coloration. Chromatin configurations, cumulus cell apoptosis, cytoplasmic maturity and developmental competence were compared between the BCB＋ and BCB- oocytes. The effects of oocyte diameter, sexual maturity and gonadotropin stimulation on the competence of BCB＋ oocytes were also analyzed. In the large- and medium-size groups, BCB＋ oocytes were larger and showed more surrounded nucleoli （SN） chromatin configurations and higher frequencies of early atresia, and they also gained better cytoplasmic maturity （determined as the intracellular GSH level and pattern of mitochondrial distribution） and higher developmental potential after in vitro maturation （IVM） than the BCB-oocytes. Adult mice produced more BCB＋ oocytes with higher competence than the prepubertal mice when not primed with PMSG. PMSG priming increased both proportion and developmental potency of BCB＋ oocytes. The BCB＋ oocytes in the large-size group showed more SN chromatin configurations, better cytoplasmic maturity and higher developmental potential than their counterparts in the medium-size group. It is concluded that BCB staining can be used as an efficient method for oocyte selection, but that the competence of the BCB＋ oocytes may vary with oocyte diameter, animal sexual maturity and gonadotropin stimulation. Taken together, the series of criteria described here would allow for better choices in selecting oocytes for better development.
