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: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
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] 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
[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
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
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
[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 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] 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] 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
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. Ethy...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, P0.05）. 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%, P0.05）. It was suggested that vitrification significantly affects the mitochondrial function and distribution in oocytes and reduces the potential of oocyte fertilization and embryo development.展开更多
Azoospermia, cryptozoospermia and necrospermia can markedly decrease the ability of males to achieve pregnancy in fertile females. However, patients with these severe conditions still have the option to be treated by ...Azoospermia, cryptozoospermia and necrospermia can markedly decrease the ability of males to achieve pregnancy in fertile females. However, patients with these severe conditions still have the option to be treated by intracytoplasmic sperm injection （ICSI） to become biological fathers. This study analyzed the fertilization ability and the developmental viabilities of the derived embryos after ICSI treatment of the sperm from these patients compared with in vitro fertilization （IVF） treatment of the proven-fertile donor sperm on sibling oocytes as a control. On the day of oocyte retrieval, the number of sperm suitable for ICSI collected from two ejaculates or testicular sperm extraction was lower than the oocytes, and therefore, excess sibling oocytes were treated by IVF with donor sperm. From 72 couples （73 cycles）, 1117 metaphase Ⅱ oocytes were divided into 512 for ICSI and 605 for IVF. Compared with the control, husbands＇ sperm produced a lower fertilization rate in nonobstructive azoospermia （65.4% vs 83.2%; P〈 0.001）, crytozoospermia （68.8% vs 75.5%; P〈 0.05） and necrospermia （65.0% vs 85.2%; P〈 0.05）. The zygotes derived in nonobstructive azoospermia had a lower cleavage rate （96.4% vs 99.4%; P 〈 0.05）, but the rate of resultant good-quality embryos was not different. Analysis of the rates of cleaved and good-quality embryos in crytozoospermia and necrospermia did not exhibit a significant difference from the control. In conclusion, although the sperm from severe male infertility reduced the fertilization ability, the derived embryos had potential developmental viabilities that might be predictive for the expected clinical outcomes.展开更多
Studies of receptor-mediated lipoprotein metabolic pathways in avian species have revealed that physiological intricacies of specific cell types are highly analogous to those in mammals. A prime example for the power ...Studies of receptor-mediated lipoprotein metabolic pathways in avian species have revealed that physiological intricacies of specific cell types are highly analogous to those in mammals. A prime example for the power of com- parative studies across different animal kingdoms, elucidated in the chicken, is that the expression of different lipo- protein receptors in somatic cells and oocytes are the key to oocyte growth. In avian species, yolk precursor transport from the hen＇s liver to rapidly growing oocytes and the subsequent transfer of yolk nutrients via the yolk sac to the developing embryo are highly efficient processes. Oocytes grow from a diameter of 5 mm to 2.5-3 cm in only 7 days, and the yolk sac transfers nutrients from the yolk stored in the mature oocyte to the embryo within just 2 weeks. The underlying key transport mechanism is receptor-mediated endocytosis of macromolecules, i.e., of hepatically synthesized yolk precursors for oocyte growth, and of mature yolk components for embryo nutrition, respectively. Recently, the receptors involved, as well as the role of lipoprotein synthesis in the yolk sac have been identified. As outlined here, lipoprotein degradation/resynthesis cycles and the expression of lipoprotein receptors are not only coordinated with the establishment of the tbllicular architecture embedding the oocyte, but also with the generation of the yolk sac vasculature essential for nutrient transfer to the embryo.展开更多
p28, a 28kD protein from toad (Bufo bufo gargarizans) oocytes, was identified by using p13sucl-agarose affinity chromatography. Sequence homology analysis of the full-length cDNA of p28 (Gene Bank accession number: AF...p28, a 28kD protein from toad (Bufo bufo gargarizans) oocytes, was identified by using p13sucl-agarose affinity chromatography. Sequence homology analysis of the full-length cDNA of p28 (Gene Bank accession number: AF 314091) indicated that it encodes a protein containing 224 amino-acids with about 55% identities and more than 70% positives to human, rat or mouse UCH-L1, and contains homological functional domains of UCH family. Anti-p28 monoclonal antibody, on injecting into the oocytes, could inhibit the progesterone-induced resumption of meiotic division in a dose-dependent manner. The recombinant protein p28 showed similar SDS/PAGE behaviors to the native one, and promoted ubiquitin ethyl ester hydrolysis, a classical catalytic reaction for ubiquitin carboxyl terminal hydrolases (UCHs). The results in this paper reveal that a novel protein, p28, exists in the toad oocytes, is a UCH L1 homolog, was engaged in the process of progesterone-induced oocyte maturation possibly through an involvement in protein turnover and degradation.展开更多
The sexual differentiation of germ cells into spermatozoa or oocytes is strictly regulated by their gonadal environment, testis or ovary, which is determined by the presence or absence of the Y chromosome, respectivel...The sexual differentiation of germ cells into spermatozoa or oocytes is strictly regulated by their gonadal environment, testis or ovary, which is determined by the presence or absence of the Y chromosome, respectively. Hence, in normal mammalian development, male germ cells differentiate in the presence of X and Y chromosomes, and female germ cells do so in the presence of two X chromosomes. However, gonadal sex reversal occurs in humans as well as in other mammalian species, and the resultant XX males and XY females can lead healthy lives, except for a complete or partial loss of fertility. Germ cells carrying an abnormal set of sex chromosomes are efficiently eliminated by multilayered surveillance mechanisms in the testis, and also, though more variably, in the ovary. Studying the molecular basis for sex-specific responses to a set of sex chromosomes during gametogenesis will promote our understanding of meiotic processes contributing to the evolution of sex determining mechanisms. This review discusses the fate of germ cells carrying various sex chromosomal compositions in mouse models, the limitation of which may be overcome by recent successes in the differentiation of functional germ cells from embryonic stem cells under experimental conditions.展开更多
Previous studies revealed that extracellular regulated kinase-1 and -2 （ERK1/2） cascade plays pivotal roles in regulating oocyte meiotic cell cycle progression. However, most knowledge about the in vivo function of ...Previous studies revealed that extracellular regulated kinase-1 and -2 （ERK1/2） cascade plays pivotal roles in regulating oocyte meiotic cell cycle progression. However, most knowledge about the in vivo function of ERK1/2 in mammalian oocytes was indirectly obtained from analyzing the phenotypes of Mos knockout mice. In this study, we knocked out Erkl and Erk2 in mouse oocytes as early as the primordial follicle stage using the well-characterized Gdp-Cre mouse model, and for the first time directly investigated the in vivo function of ERK1/2 in mouse oocytes. In this novel mouse model, we observed that ERK1/2 activities in oocyte are dispensable for primordial follicle maintenance, activation and follicle growth. Different from the Mos null oocytes, the ERK1/2-deleted oocytes had well-assembled spindles at metaphase I （MI）, extruded polar body-I （PB1） with normal sizes, and did not undergo a full parthenogenetic activation characterized for pronuclear formation. However, the ovulated ERK1/2-deleted oocytes had poorly-assembled metaphase II （MII） spindles, spontaneously released polar body-2 （PB2）, and were arrested at another metaphase called metaphase III （MIII）. In addition, ERK1/2 deletion prevented male pronuclear formation after fertilization, and caused female infertility. In conclusion, these results indicate that ERK1/2 activities are required for not only MII-arrest maintenance, but also efficient pronuclear formation in mouse oocytes.展开更多
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.
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.
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.
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.
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.
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.
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 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 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 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 Foundation of Hubei Provincial Health Department,China(No.JX5A02)
文摘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, P0.05）. 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%, P0.05）. It was suggested that vitrification significantly affects the mitochondrial function and distribution in oocytes and reduces the potential of oocyte fertilization and embryo development.
基金The work was supported by grants from the Shanghai Committee of Science and Technology, China （Grant No. 09411964200）, the Major State Basic Research Development Program of China （973 Program, No. 2014CB943104） and the National Natural Science Foundation of China （81270744）.
文摘Azoospermia, cryptozoospermia and necrospermia can markedly decrease the ability of males to achieve pregnancy in fertile females. However, patients with these severe conditions still have the option to be treated by intracytoplasmic sperm injection （ICSI） to become biological fathers. This study analyzed the fertilization ability and the developmental viabilities of the derived embryos after ICSI treatment of the sperm from these patients compared with in vitro fertilization （IVF） treatment of the proven-fertile donor sperm on sibling oocytes as a control. On the day of oocyte retrieval, the number of sperm suitable for ICSI collected from two ejaculates or testicular sperm extraction was lower than the oocytes, and therefore, excess sibling oocytes were treated by IVF with donor sperm. From 72 couples （73 cycles）, 1117 metaphase Ⅱ oocytes were divided into 512 for ICSI and 605 for IVF. Compared with the control, husbands＇ sperm produced a lower fertilization rate in nonobstructive azoospermia （65.4% vs 83.2%; P〈 0.001）, crytozoospermia （68.8% vs 75.5%; P〈 0.05） and necrospermia （65.0% vs 85.2%; P〈 0.05）. The zygotes derived in nonobstructive azoospermia had a lower cleavage rate （96.4% vs 99.4%; P 〈 0.05）, but the rate of resultant good-quality embryos was not different. Analysis of the rates of cleaved and good-quality embryos in crytozoospermia and necrospermia did not exhibit a significant difference from the control. In conclusion, although the sperm from severe male infertility reduced the fertilization ability, the derived embryos had potential developmental viabilities that might be predictive for the expected clinical outcomes.
基金supported by Research Grants from the Austrian Science Fundthe Austrian National Bankthe Herzfelder Family Endowment
文摘Studies of receptor-mediated lipoprotein metabolic pathways in avian species have revealed that physiological intricacies of specific cell types are highly analogous to those in mammals. A prime example for the power of com- parative studies across different animal kingdoms, elucidated in the chicken, is that the expression of different lipo- protein receptors in somatic cells and oocytes are the key to oocyte growth. In avian species, yolk precursor transport from the hen＇s liver to rapidly growing oocytes and the subsequent transfer of yolk nutrients via the yolk sac to the developing embryo are highly efficient processes. Oocytes grow from a diameter of 5 mm to 2.5-3 cm in only 7 days, and the yolk sac transfers nutrients from the yolk stored in the mature oocyte to the embryo within just 2 weeks. The underlying key transport mechanism is receptor-mediated endocytosis of macromolecules, i.e., of hepatically synthesized yolk precursors for oocyte growth, and of mature yolk components for embryo nutrition, respectively. Recently, the receptors involved, as well as the role of lipoprotein synthesis in the yolk sac have been identified. As outlined here, lipoprotein degradation/resynthesis cycles and the expression of lipoprotein receptors are not only coordinated with the establishment of the tbllicular architecture embedding the oocyte, but also with the generation of the yolk sac vasculature essential for nutrient transfer to the embryo.
基金This work is supported by National Natural Sci-ence Fundation of China (Grant 39770370), and National Laboratory of Contraceptives and Devices Re-search affiliated with Shanghai lnstitute of Planned Parenthood Research.
文摘p28, a 28kD protein from toad (Bufo bufo gargarizans) oocytes, was identified by using p13sucl-agarose affinity chromatography. Sequence homology analysis of the full-length cDNA of p28 (Gene Bank accession number: AF 314091) indicated that it encodes a protein containing 224 amino-acids with about 55% identities and more than 70% positives to human, rat or mouse UCH-L1, and contains homological functional domains of UCH family. Anti-p28 monoclonal antibody, on injecting into the oocytes, could inhibit the progesterone-induced resumption of meiotic division in a dose-dependent manner. The recombinant protein p28 showed similar SDS/PAGE behaviors to the native one, and promoted ubiquitin ethyl ester hydrolysis, a classical catalytic reaction for ubiquitin carboxyl terminal hydrolases (UCHs). The results in this paper reveal that a novel protein, p28, exists in the toad oocytes, is a UCH L1 homolog, was engaged in the process of progesterone-induced oocyte maturation possibly through an involvement in protein turnover and degradation.
文摘The sexual differentiation of germ cells into spermatozoa or oocytes is strictly regulated by their gonadal environment, testis or ovary, which is determined by the presence or absence of the Y chromosome, respectively. Hence, in normal mammalian development, male germ cells differentiate in the presence of X and Y chromosomes, and female germ cells do so in the presence of two X chromosomes. However, gonadal sex reversal occurs in humans as well as in other mammalian species, and the resultant XX males and XY females can lead healthy lives, except for a complete or partial loss of fertility. Germ cells carrying an abnormal set of sex chromosomes are efficiently eliminated by multilayered surveillance mechanisms in the testis, and also, though more variably, in the ovary. Studying the molecular basis for sex-specific responses to a set of sex chromosomes during gametogenesis will promote our understanding of meiotic processes contributing to the evolution of sex determining mechanisms. This review discusses the fate of germ cells carrying various sex chromosomal compositions in mouse models, the limitation of which may be overcome by recent successes in the differentiation of functional germ cells from embryonic stem cells under experimental conditions.
基金supported by the National Basic Research Program of China (Nos. 2011CB944504 and 2012CB944403)the National Natural Science Foundation of China (Nos. 81172473 and 31371449)
文摘Previous studies revealed that extracellular regulated kinase-1 and -2 （ERK1/2） cascade plays pivotal roles in regulating oocyte meiotic cell cycle progression. However, most knowledge about the in vivo function of ERK1/2 in mammalian oocytes was indirectly obtained from analyzing the phenotypes of Mos knockout mice. In this study, we knocked out Erkl and Erk2 in mouse oocytes as early as the primordial follicle stage using the well-characterized Gdp-Cre mouse model, and for the first time directly investigated the in vivo function of ERK1/2 in mouse oocytes. In this novel mouse model, we observed that ERK1/2 activities in oocyte are dispensable for primordial follicle maintenance, activation and follicle growth. Different from the Mos null oocytes, the ERK1/2-deleted oocytes had well-assembled spindles at metaphase I （MI）, extruded polar body-I （PB1） with normal sizes, and did not undergo a full parthenogenetic activation characterized for pronuclear formation. However, the ovulated ERK1/2-deleted oocytes had poorly-assembled metaphase II （MII） spindles, spontaneously released polar body-2 （PB2）, and were arrested at another metaphase called metaphase III （MIII）. In addition, ERK1/2 deletion prevented male pronuclear formation after fertilization, and caused female infertility. In conclusion, these results indicate that ERK1/2 activities are required for not only MII-arrest maintenance, but also efficient pronuclear formation in mouse oocytes.
