Relationship between ATP Content and the Developmental Potential of Human Oocytes

To investigate the relationship between the ATP content in human oocytes and the deve-lopmental potential of human oocytes, unfertilized oocytes from clinical IVF and immature oocytes unsuitable for ICSI were collected. The ATP content of these unfertilized and in vitro matured eggs were determined quantitatively by measuring the luminescence using an ATP-dependent bioluminescence assay. The result showed that the ATP content of unfertilized oocytes was higher than in vitro matured ones (2.20±0.67 pmol vs 1.72±0.49 pmol, P<0.05 ). In unfertilized oocytes, the ATP content of those whose fertilization rates (FR) was higher than 50 % was 2.43±0.60 pmol, which was significantly different from those whose FR was less than 50 % (1.72±0.56 pmol), while in in vitro matured oocytes, the ATP content of those whose FR more than 50 % was 1.8±0.44 pmol, slightly higher than those less than 50 % (1.55±0.40 pmol), without statistical significance. There was a tendency that the ATP content of oocytes of pregnant patients was higher than those of controls, but the sample number was too small to show any significance in statistics. Briefly, there was positive correlation between the ATP content in oocytes and developmental potential of oocytes.

Developmental Competence of Frozen-thawed Germinal Vesical Porcine Oocytes by Vitrification Method following Maturation,Fertilization and Culture In Vitro

The purpose of this study was to evaluate the viability and subsequent developmental ability of porcine germinal vesicle（GV） oocytes vitrified step-wise exposure to cryoprotectants. Oocytes were transferred to a vitrification solution composed of 10% ethylene glycol（EG）,10% dimethyl sulfoxide（DMSO）, 300 g/L-1 Ficoll and 0.5 mol/L-1 sucrose（EDFS40） in a direct manner （non-preequilibrium） or in step-wise manner（ single- and two-step preequilibrium）. After vitrification and storage in liquid nitrogen, the oocytes were thawed,washed and in vitro maturation, fertilization and culture. In the non-preequilibrium group, the rates of post-thawed oocytes surviving, maturing to metaphase-Ⅱ, cleavage rate and blastocysts rate was significantly lower than that of sigle- and two-step preequilubrium groups（P<0.05）. In the single- and two- step groups, the rates of metaphase-Ⅱ stage were 46.8%, 42.7% and 49.7%, respectively, the rates which developed to blastocysts were 10.5%,11.1% and 14.8%, respectivaly. In the non-vitrified control group,the rates of oocytes maturing to metaphase-Ⅱ, developing to blastocysts was significantly higher than that vitrified groups（P<0.05）. The present study shows that the vitrification of porcine GV oocytes by a step-wise method involving two-steps preequilibrium may have advantage in maintaining the viability and subsequent production of blastocysts.

Effects of β-mercaptoethanol Concentrations on Developmental Ability of Oocytes in 6-week-old Dorper Sheep

This study was conducted to investigate the effects of different concentrations ofβ-mercaptoethanol on the development ability of oocytes in Dorper sheep at the age of 6 weeks.In this study,6 Dorper sheep of 6 weeks old were chosen to induce oocyte collection in vivo by gonadotropin,and A and B grade cumulus oocyte complexes were obtained(COCs)with different concentrations of(0,50,70 and 100μmol/L)ofβ-mercaptoethanol in the mature liquid.The cleavage rate and blastocyst rate were counted after matured oocytes and capacitated sperm were co-incubated and fertilized eggs were cultivated.The results showed that compared with the cleavage rate(59.13%)and the blastocyst rate(12.17%)of the control group,the cleavage rates(60.87%,63.48%and 65.22%)and blastocyst rates(14.78%,17.39%and 21.74%)of the test groups I,II and III were higher(P>0.05),and the order was test group III>test group II>test group I>control group.The cleavage rate and blastocyst rate of the 100μmol/Lβ-mercaptoethanol group increased by 6.09 percentage points and 9.57 percentage points,respectively.It indicated that the addition of a certain amount ofβ-mercaptoethanol in the mature liquid could improve the developmental ability of oocytes and the quality of fertilized eggs of the 6-week-old Doper sheep.When theβ-mercaptoethanol concentration was within 100μmol/L,the cleavage rate and the blastocyst rate of oocytes were on the rise.The optimal concentration ofβ-mercaptoethanol in the mature liquid still needs further study.

Impact of Luveris and Gonal-F on bovine immature oocytes developmental competence in vitro

Objective: To investigate the gonadotrophin drug Luveris? (L) and Gonal-F? (G) effects on bovine immature oocyte in vitro maturation culture. Methods: In total, 2000 bovine cumulus-oocyte complexes (COCs) were purchased commercially and cultured in media with ovulation stimulation drugs Gonal-F and Luveris (0, 5, 10, 20, 40 IU/mL), individually, for maturation in vitro. 2000 Oocytes were divided evenly into two groups, Luveris and Gonal-F groups, individually, 1000 Oocytes. After 24 and 48h culture, cumulus expansion was assessed under dissecting microscopes. Oocyte maturation (GV, MI, MII) was determined by examining nuclear maturation and polar body formation under inverted microscopes. Results: Luveris and Gonal-F enhanced oocyte maturation in vitro in a dose-dependently manner. Culture media supplemented with L or G significantly improved MⅡ Oocyte maturation rates after culture for 24 h and 48 h in comparison with the control group. Oocyte maturation rates were 33.3% and 37.5%(20 IU/mL), individually, 33.3% and 53.6% (40 IU/mL);20 IU/mL G was 15.1% and 16.2%;40 IU/mL G was 38.9% and 39.5%, respectively. Conclusion: LH (Luveris) can promote prophase bovine immature oocytes developmental competence in vitro, which is mostly likely stimulated by FSH(Gonal-F ). Furthermore, LH can delay oocytes GVBD that is very useful for IVF clinical medication guidance.

Embryonic, genetic and clinical outcomes of fresh versus vitrified oocyte: A retrospective cohort study

Objective:To compare embryonic development,ploidy status and clinical outcomes between fresh and frozen-thawed oocytes.Methods:This retrospective cohort study evaluated 83 fertilization cycles including both fresh and frozen oocytes from 79 patients at the HP Fertility Center of Hai Phong International Hospital of Obstetrics and Pediatrics in Vietnam.The patient underwent several ovarian stimulation cycles to accumulate a certain number of oocytes that would be vitrified.In the last oocyte retrieval,all patient’s oocytes including both frozen and fresh would be fertilized.The outcomes included the rates of oocyte survival,cleavage embryo,blastocyst,ploidy status,pregnancy,biochemical pregnancy and clinical pregnancy.Results:The oocyte survival rate after thawing was 96.5%.No statistically significant difference was found when comparing fresh and frozen oocytes regarding fertilization rate(78.1%vs.75.5%,P=0.461),usable cleavage embryo rate(86.9%vs.87.2%,P=0.916)but usable blastocyst rate was found higher statistically in the frozen oocyte group(44.4%vs.54.0%,P=0.049).The percentages of euploid,aneuploid and mosaic embryos between the fresh group and the vitrified group had no significant differences(33.8%vs.31.6%,P=0.682;51.0%vs.54.2%,P=0.569;15.2%vs.12.4%,P=0.787;respectively).The rates of pregnancy,biochemical pregnancy and clinical pregnancy had no statistical difference(68.8%vs.64.8%,P=0.764;12.5%vs.3.6%,P=0.258;37.5%vs.46.4%,P=0.565).17 Mature oocytes are the minimum to have at least one euploid embryo.Conclusions:Oocyte vitrification does not affect embryonic,genetic and clinical results.The number of mature oocytes should be considered for fertilization in some cases.

Effect of GPAG Supplement on Porcine Oocyte Maturation and Its Following Embryonic Development by Parthenogenetic Activated

The aim of this study was to compare the effect of GPAG and commonly used FCS on porcine oocyte maturation and subsequent embryonic development after the fertilization. COCs were aspirated from follicles and cultured for 16, 24, 32, 40 and 48 h in TCM-199 medium either with GPAG or FCS. After 24 h with GPAG, 89.4% of oocytes reached M Ⅰ stage while in the medium supplemented with FCS, only 27.7% of oocytes reached the same stage （P〈0.05）. Prolonged incubation for up to 32 h clearly demonstrated that some of oocytes cultured in GPAG medium were at M Ⅱ stage （35.7%）, few of oocytes from FCS medium were at M Ⅱ stage （7.5%） （P〈0.05）. Both groups of oocytes reached the same stage of maturation within 48 h. After 48 h of culture, the oocytes with extruded polar bodies were inseminated. Fertilized oocytes were cultured in PZM3 medium supplemented with 3 mg.mL of BSA. After 7 days, the development and the quality of embryos were evaluated. The results showed that the maturation of oocytes in the presence of GPAG significantly increased their subsequent developmental ability when compared with FCS supplementation （29.2% ： 18.9% of blastocysts, P〈0.05）. However, differential staining revealed that once blastocysts were formed in either group, they had the same total cell number （39 ： 38） and the ICM/total cell ratio （0.26 ： 0.28）

Effects of Medium on in Vitro Maturation of Pig Oocytes and in Vitro Early Development of Parthenogenetic Embryos

[ Objective] To improve quality of oocytes maturing in vitro and to optimize in vitro culture system of porcine early embryos. [ Method ] Oocytes were cultured in the improved TCM199 and NCSU-23 basic media, which were added pig follicular fluid （PFF） or high-quality fetal bovine serum （FBS） both at a proportion of 10% （V/V）. After in vitro maturation and development, effects of medium on maturation of pig oocytes and development of eady parthenogenetic embryos were investigated using maturing rate of pig oocytes and development rate of parthenogenetic embryos as indicators. [ Result] After 42 h culture, the maturing rates of pig oocytes respectively cultured in the TCM199, TCM199 added FBS, TCM199 added PFF, NCSU-23, NCSU-23 added FBS and NCSU-23 added PFF were （54.2 ±3.5）%, （68.5 ±3.2）%, （69.3 ±3.7）%, （51.6 ±3.3）%, （63.2 ±3.1 ）% and （65.5 ±3.5）%, respectively. The pig oocytes cultured in the TCM199 or NCSU-23 that was added FBS or PFF had significantly higher maturing rate （P 〈 0.05）. The development rates of parthenogenetic embryos were not significantly different between these six experimental media. However, the parthenogenetic embryos which developed in the TCM199 added PFF （36.5 ±4.8） had significantly more blastomeres than those developed in the TCM199 or NCSU-23 （ 18.7 ± 3.2 and 15.5 ± 2.4, respectively） （ P 〈 0.05）. [ Conclusion ] The improved TCM199 and NCSU-23 added PFF or FBS can largely promote in vitro maturation of pig oocytes and in vitro development of early parthenogenetic embryos.

Effect of Different Antioxidants on in vitro Development of Mammalian Oocytes

In vitro maturation of mammalian oocytes is a key step during in vitro production of mammalian embryos. Studies have shown that the level of oocyte maturation is positively correlated with embryo cleavage rate and blastocyst rate. However,reactive oxygen species（ ROS） in vitro is one of the main influencing factors of oocyte maturation. The results indicate that the addition of antioxidants can effectively improve in vitro oocyte maturation level and reduce the adverse effects of reactive oxygen species,which contribute to oocyte development. This paper summarizes research progresses on the effects of different antioxidants on in vitro development of mammalian oocytes,which is conducive to further analysis of the mechanism of action.

High pregnancy and implantation rates can be obtained with preincubation of oocytes before insemination in IVF and ICSI procedures

Purpose: Evaluate the effect of preincubation of oocytes prior to IVF or ICSI cycles with embryo transfer at blastocyst stage. Methods: Retrospective non randomized study based on secondary analysis of data. Setting: Laboratory of Assisted Reproduction at the Alcivar Hospital. Patients: One hundred-eighteen cycles of IVF and ICSI were analyzed in the present study. The evaluated groups were formed for those patients whose oocytes, after retrieval, were inseminated at 1-3 h (Group I) or 4-6 h (Group II). Results: There was no difference in fertilization rate (83.6% and 78.1%), Day 3 cleavage rate (95.1% and 97.1%), and blastocyst formation (31.1% and 39.1%) for groups I and II respectively. Clinical pregnancy rates (PR: 53.0% vs 22.9%) and implantation rates (IR: 38.1% vs 13.0%) were significantly higher in group II versus group I, respectively (P < 0.05). Conclusions: Preincubation of oocytes before insemination is a factor which raises the PR and IR after the blastocyst transfer.

Improvement of cortical granules migration andin vitro embryo production of vitrified bovine oocyte by 9-cis retinoic acid

Objective:To reveal the effects of 9-cis retinoic acid (RA) on cortical granules (CGs) migration andin vitro embryo production (IVP) rate in meiosisⅡvitrified bovine oocyte. Methods:Followingin vitro maturation (IVM) in a medium containing 5 nM of 9-cis-RA, 60 oocytes were vitrified and then thawed. Then, half of them were evaluated for CGs migration and the other half were used for in vitro fertilization and IVP (on day 3). In addition, the other 60 oocytes were considered as the control group, which did not receive RA in IVM medium. The data were presented to one way analysis of variance (ANOVA) and Duncan's test.Results:Results showed that IVP rate (4-8 cells embryos) was significantly (P<0.05) higher than the control group when RA had been added to IVM medium. Furthermore, the presence of RA in IVM medium improved the rate and mode of CGs migration so that the rate of oocytes that had completed CGs migration in the group, which had received RA, was significantly higher than the control group.Conclusions:This study shows that presence of RA in IVM medium enhances the developmental competence and CGs distribution of meiosisⅡvitrified bovine oocyte. Therefore, adding RA in IVM medium can decrease the ultrastructural changes during vitrification and can improve the efficiency of bovine oocyte vitrification.

Oocyte quality improvement using a herbal medicine comprising 7 crude drugs

Maternal age is a significant factor in infertility treatment. Ovarian function and oocyte quality decrease with age, whereas the frequency of chromosomal abnormalities increases. In this study, improvement of oocyte quality and ovarian function were attempted using a herbal medicine comprising 7 crude drugs:Angelicae radix,Rehmanniae radix,Plantaginis semen,Lonicerae flos,Carthami flos,Ginseng radix, andCucurbita moschata Duch. Thirty-one women who repeatedly failed to conceive by intracytoplasmic sperm injection took the herbal medicine before breakfast and dinner from the start of menstrual cycle in the ovum pickup cycle. Average patient age was 38.5 ± 0.7 years, and the average ovum pickup frequency on the first dosage day was 7.9 ± 1.5. To analyze the effects of herbal medicine intake, the number of recovered and mature oocytes, their morphology and physical qualities, as well as the rates of fertilization, oocyte development, and pregnancy was compared before and after intake. The recovered and mature oocyte numbers, oocyte morphology and physical qualities, and fertilization rate were not significantly different before and after drug intake. However, the oocyte development rate was significantly higher(58.0%) after herbal medicine intake than before (32.5%;p = 0.0003). Moreover, the successful pregnancy rate was significantly higher after intake than before (6.9% versus 0%;p = 0.0111). Herbal medicine may constitute a useful adjunct to assisted reproductive technology in women.

Effect of Oocyte Recovery Techniques on in Vitro Production of Swine Embryos

In Vitro production of swine embryos is a valuable tool to generate clones and genetically modified pigs during a short period of time. However, the efficiency of the existing methods is extremely low and the oocyte quality and quantity represent important obstacles on the success of in Vitro production of embryos. Therefore, the aim of this study was to compare the in Vitro maturation, fertilization and subsequent embryo development rates of oocytes recovered by ovary slicing or follicular aspiration. The oocyte recovery rate (grade 1 COC/ovary) was higher (p = 0.0083) in the slicing group when compared to the aspiration group. No differences were observed between groups regarding in Vitro maturation and early cleavage rates. A higher percentage of oocytes recovered by follicular aspiration reached the blastocyst stage after IVF when compared to the ovary slicing method (p = 0.0395). However, no difference on blastocyst cell number was observed. Although the recovery of oocytes using the slicing technique yielded more grade 1 oocytes per ovary than the aspiration method, the number of oocytes that reached the blastocyst stage after IVF by the slicing method was lower when compared with oocytes obtained by aspiration, as observed by lower blastocyst rates. In conclusion, the follicular aspiration is the method of choice for porcine in Vitro embryo production.

热应激对牛卵子及其胚胎表观遗传修饰与发育能力的影响

旨在探究热应激对牛卵子及其胚胎表观遗传修饰与发育能力的影响。本研究将卵子置于体外热应激条件下培养(41℃12 h+38.5℃12 h),进行体外成熟(in vitro maturtion, IVM)和体外受精(in vitro fertilization, IVF),检测对照组(38.5℃24 h)和热应激组牛卵子和胚胎的发育能力及表观遗传修饰组蛋白H1、组蛋白H2、组蛋白H4和DNA甲基化的修饰水平。本研究还检测了卵子活性氧(reactive oxygen species, ROS)水平、线粒体膜电位(mitochondrial membrane potential,ΔΨm)水平及与表观遗传修饰和发育能力相关基因的表达水平。结果表明,热应激处理组卵子成熟率((59.21±4.29)%)、卵裂率((57.78±4.58)%)和囊胚率((22.31±1.67)%)均显著低于对照组((85.10±6.75)%、(78.64±2.46)%、(42.64±1.38)%,P<0.05);热应激组牛卵子及各阶段胚胎表观遗传修饰组蛋白H1、组蛋白H2、组蛋白H4、DNA甲基化水平显著低于对照组(P<0.05);热应激组牛卵子ΔΨm水平显著低于对照组(P<0.05);热应激组牛卵子ROS水平显著高于对照组(P<0.05);热应激组牛卵子表观遗传修饰相关基因DNMT1、DNMT3A、DNMT3B、Histone H2A、SMYD3、IGF-2R的mRNA表达水平显著低于对照组(P<0.05);热应激组牛卵子发育能力相关基因C-MOS、GDF-9和POU5F1的mRNA表达水平显著低于对照组(P<0.05)。本研究表明,热应激显著降低了牛卵子和胚胎表观遗传修饰组蛋白H1、组蛋白H2、组蛋白H4、DNA甲基化水平,显著降低了牛卵子ΔΨm水平及与表观遗传修饰和发育能力相关基因的mRNA表达水平,显著提高了ROS水平,降低了卵子质量。

多次超数排卵对小鼠和人卵母细胞发育潜能的影响

背景:超数排卵是辅助生殖技术中常见的治疗方法。在临床实践中,一些患者需要经过多次超数排卵怀孕。目的:探讨多次超数排卵对小鼠和人卵母细胞发育潜能的影响。方法:采用动物实验和临床回顾性研究。动物实验选择90只SPF级ICR 8周龄雌性小鼠,随机分为3组,分别进行1次、3次和5次超数排卵。在临床研究中共纳入306例接受3个体外受精周期的患者,比较不同周期的获卵数和胚胎发育情况。结果与结论:①在动物实验中,多次超数排卵不影响小鼠胚胎的发育率和发育速度,且对小鼠囊胚细胞凋亡、DNA损伤、内细胞团和滋养外胚层的形成均无显著影响(P>0.05);②在临床研究中,3个周期内获得的卵母细胞数(8.60±5.04,8.58±4.87及8.38±4.63,P=0.81)和可移植胚胎数(2.42±1.99,2.40±1.92及2.64±2.00,P=0.26)均无显著差异;③对于年轻组(<35岁)和高龄组(≥35岁),胚胎质量不受超数排卵次数的影响(P>0.05);④结果显示:多次超数排卵不影响小鼠和人卵母细胞的发育潜能。

家畜卵母细胞玻璃化冷冻损伤研究进展

卵母细胞玻璃化冷冻保存对加快优良品种繁育、提高畜牧生产效率、维持物种多样性、拯救濒危动物具有重要意义。目前玻璃化冷冻技术已广泛应用于猪、牛、羊等家畜卵母细胞的冷冻保存。然而,相较新鲜卵母细胞,冷冻-解冻后卵母细胞的成熟率、受精率、卵裂率及囊胚发育率仍然偏低,这显著影响卵母细胞冷冻保存的实际应用。冷冻损伤是制约卵母细胞保存效率与质量的关键。玻璃化冷冻引起卵母细胞透明带破裂、膜脂相变、DNA损伤、染色体异常及胞质内皮质颗粒分布异常、内质网和线粒体结构功能受损、纺锤体形态异常等结构损伤,以及引起细胞氧化应激和钙稳态失衡等生理状态紊乱,导致细胞发育能力降低。因此,认识冷冻损伤产生的原因及其损伤机制,有助于进一步提高卵母细胞冷冻保存效率,促进卵母细胞冷冻技术的提升。作者综述了家畜卵母细胞冷冻损伤类型,分析了冷冻损伤原因,针对不同类型的冷冻损伤提出了改善方法,并对其研究前景进行展望,旨在为提高卵母细胞冷冻保存效率和质量提供参考。

卵巢多囊样改变合并不孕症患者AMH水平对卵母细胞发育潜能的影响

目的探讨卵巢多囊样改变(polycystic ovarian morphology,PCOM)合并不孕症患者体外受精-胚胎移植中抗苗勒管激素(anti-Müllerian hormone,AMH)水平对卵母细胞发育潜能的影响。方法选取符合纳入与排除标准的不孕症患者480例(对照组160例、PCOM组104例、PCOS组216例),比较不同组间AMH水平。PCOM及PCOS人群均按血清AMH水平(≤4.7ng/ml为正常值,>4.7ng/ml为高值)分为正常AMH组和高AMH组,分析PCOM及PCOS人群不同AMH水平组间的卵母细胞指标差异及其相关性。结果PCOS人群血清基础雄激素高于PCOM人群(P<0.01);血清AMH水平比较:对照组<PCOM组<PCOS组(P<0.001);实验室指标分析结果显示,PCOM及PCOS人群高AMH组成熟卵数、2PN数、受精数、D3卵裂数及胚胎总数较正常AMH组增多(P<0.05),且AMH水平与成熟卵数、2PN数、受精数、D3卵裂数、胚胎总数均呈正相关(P<0.05);PCOS人群高AMH组优势卵泡数、获卵数、优胚数及可利用胚胎数较正常AMH组增多(P<0.05),且AMH水平与优势卵泡数、获卵数、优胚数及可利用胚胎数均呈正相关(P<0.05),但PCOM人群中不同AMH水平组间的上述指标比较,差异无统计学意义(P>0.05)。结论PCOM合并不孕症人群血清AMH水平较对照组升高但低于PCOS人群,高AMH水平的PCOM患者可获得质量较好的卵母细胞及更多的胚胎,增加临床中反复移植失败患者移植次数,提高临床妊娠率。

Effect of using ascorbic acid and cysteamine supplementation onin-vitrodevelopment of buffalo embryos

Objective:To improvein vitro embryo production in buffalo by supplementation of L-ascorbic acid during maturation and development (experiment 1) and combination with another antioxidant as cysteamine (experiment 2).Methods:Two experiments were performed, the first one aimed to evaluate the different concentrations (0, 25, 50, 100 μM) of L-ascorbic acid on embryo developmental rate of buffalo oocytes. The L-ascorbic acid was added to the maturation and culture media. In the second experiment, oocytes were cultured in media with two type of antioxidant (ascorbic acid + cysteamine) or ascorbic acid only.Results:There was a significant increase in cleavage rate at 25, 50 μM than 100 μM and control group. But, the blastocyst rate was higher at 50 μM ascorbic acid than other concentrations (0, 25, 100 μM). Supplementation of ascorbic acid and cysteamine to maturation and cultured media improved embryo development than ascorbic acid alone.Conclusions: Using of 50 μM L-ascorbic acid duringin vitro maturation and development improve the developmental competence of buffalo oocytes, this effect was increase with the presence of cysteamine.

Effects of Heyan Kuntai Capsule(和颜坤泰胶囊)on Follicular Development and Oocyte Cohesin Levels in Aged Mice

Objective： To evaluate the effect of Heyan Kuntai Capsule （和颜坤泰胶囊, HYKT） on the ovarian function of aged mice and expressions of cohesion complexes in oocytes. Methods： Twenty-five 9-month-old female C57BL/6J mice were randomly divided into 5 groups by block randomization method （n=5 per group）, including the control group （saline）, 17β-estradiol group [E2, 100 μg/（kg·d）], and low-, medium-, and high- dose of HYKT groups [0.3, 0.9, 2.7 g/（kg·d）, respectively]. All mice were treated by intragastric administration for 4 weeks. Hematoxylin and eosin staining and anti-VASA staining were used to detect the amounts of follicles. The apoptosis of follicles was measured by anti-gamma H2A histone family member X （γ, H2AX） staining and TdT-mediated dUTP Nick-End Labeling （TUNEL） assay. The density of cohesin subunits, REC8 meiotic recombination protein （REC8）, structural maintenance of chromosome （SMC） 1 β and SMC3 in oocytes were evaluated by immunofluorescent staining. Results： After administration of E2 and high-dose of HYKT, the total number of follicles as well as the number of primordial and primary follicles were significantly increased （P〈0.05）. Anti-γ/H2AX staining and TUNEL assay demonstrated that high-dose of HYKT and E2 partly suppressed the apoptosis of follicles （P〈0.05）. Furthermore, it showed an increased trend in the levels of REC8 and SMC1 β, after administration with E2 and HYKT, and no obvious change in the level of SMC3. Conclusion： HYKT could enhance the number of follicles, suppress apoptosis of oocytes and have a trend to elevate the meiotic-specific cohesin subunits （REC8 and SMC1 β） in oocytes of aged mice, indicating a beneficial effect on the ovarian function in terms of the quantity and quality of follicles.

Characterization of H3 methylation in regulating oocyte development in cyprinid fish

Histone post-modifications are important epigenetic markers involved in multiple cellular processes via regulation of gene transcription or remodeling of chromatin structure. Oocyte development is a critical process under rigorous control to prevent the generation of aberrant gametes. However, the regulatory mechanism of oocyte early development is not well-understood due to the tiny size and poor distinguishability of the gonad in juvenile stages. Here, two cyprinid hybrid fishes, a sterile allotriploid fish and a gynogenetic hybrid fish with delayed oocyte development, provided research models to investigate the mechanisms involved. We used cytogenetic and molecular methods to confirm the pachytene arrest of oocytes in allotriploid fish and gynogenetic hybrid fish. On the basis of these developmental differences, we screened 21 different histone H3 modifications by ELISA and found that four modifications(H3 K4 me3, H3 K9 me3, H3 K79 me, and H3 K79 me3) differed significantly in the two cyprinid hybrid fishes. Changes in histone methylation at the three residues(H3 K4, K9, K79) were caused by specific methyltransferases and demethylases. Our results provide new insights into the epigenetic regulation of oocyte early development in fish, a process critical for understanding of reproductive biology and with practical applications in the aquacultural breeding industry.

Role of functional fatty acids in modulation of reproductive potential in livestock

Fatty acids are not only widely known as energy sources,but also play important roles in many metabolic pathways.The significance of fatty acids in modulating the reproductive potential of livestock has received greater recognition in recent years.Functional fatty acids and their metabolites improve follicular development,oocyte maturation and embryo development,as well as endometrial receptivity and placental vascular development,through enhancing energy supply and precursors for the synthesis of their productive hormones,such as steroid hormones and prosta-glandins.However,many studies are focused on the impacts of individual functional fatty acids in the reproductive cycle,lacking studies involved in deeper mechanisms and optimal fatty acid requirements for specific physiological stages.Therefore,an overall consideration of the combination and synergy of functional fatty acids and the establish-ment of optimal fatty acid requirement for specific stages is needed to improve reproductive potential in livestock.