In vitro maturation and glutathione synthesis of porcine oocytes in the presence or absence of cysteamine under different oxygen tensions: role of cumulus cells

The present study was conducted to evaluate the effect of cumulus cells on the in vitro maturation (IVM) and glutathione (GSH) synthesis of porcine oocytes cultured in the presence or absence of cysteamine under different oxygen tensions, and on their subsequent male pronucleus formation after in vitro fertilization (IVF). Cumulus-oocyte complexes (COCs) and cumulus-denuded oocytes (DOs) were cultured for 45 h in modified TCM-199 supplemented with or without 150 microM cysteamine under a humidified atmosphere of 5% CO2 in air (20% O2) or 5% CO2, 5% O2 and 90% N2. When cultured in medium supplemented with cysteamine under 20% O2 tension, the rates of COC maturation to the metaphase II (MII) stage were significantly higher than those of DOs (P<0.05). Regardless of the addition of cysteamine and oxygen tension, the rates of male pronucleus formation in COCs after IVM and IVF were significantly higher than in DOs (P<0.05). The GSH content of oocytes was significantly increased by the addition of cysteamine to the maturation medium (P<0.05), with significantly higher GSH content in COCs than in DOs (P<0.05). However, the GSH content of COCs and DOs was not significantly different when cultured in medium without cysteamine. These results indicate that cumulus cells play an important role in nuclear maturation to MII, GSH synthesis in porcine oocytes cultured in the presence of cysteamine, and subsequent male pronucleus formation after IVF.     

Nuclear morphology,diameter and meiotic competence of buffalo oocytes relative to follicle size

The nuclear morphology, diameter and in vitro meiotic competence of buffalo oocytes was compared relative to follicle size. Cumulus-oocyte complexes (COCs) were collected from 1-<2, 2-<3, 3-<4, 4-<6 and 6-<8 mm follicles from abattoir ovaries. Cumulus cells were removed using 3 mg mL(-1) hyaluronidase in saline and repeated pipetting. Denuded oocytes were measured, fixed in 3% glutaraldehyde, stained with 4,6-diamidoino-2-phenylindole and evaluated for nuclear morphology, namely the stage of germinal vesicle (GV) development before in vitro maturation (IVM). The COCs from >2-mm follicles were matured in vitro in their respective size groups for 24 h in Medium 199 supplemented with 10 microg mL(-1) follicle-stimulating hormone, 10 microg mL(-1) luteinizing hormone, 1.5 microg mL(-1) oestradiol, 75 microg mL(-1) streptomycin, 100 IU mL(-1) penicillin, 10 mM HEPES and 10% fetal bovine serum. Matured oocytes were fixed, stained and evaluated for GV status and meiotic development. The number of oocytes collected from follicles 1-<8 mm in diameter averaged 1.82 per ovary. Oocytes from follicles 1-<2 mm (107.7 +/- 1.6 microm), 2-<3 mm (108 +/- 1.1 microm) and 3-<4 mm (114.6 +/- 1.3 microm) in diameter were smaller in diameter (P < 0.05) than oocytes from follicles 4-<6 mm (124.4 +/- 1.3 microm) and 6-<8 mm (131.9 +/- 1.4 microm) in diameter. A majority of oocytes (P< 0.05) from <4-mm follicles was at the initial stages of GV development (GV-I, II and III), whereas oocytes from 4-<6- and 6-<8-mm follicles were at the final stages of GV-IV (35.0 and 21.6% respectively) and GV-V (49.1 and 67.5% respectively). Poor IVM rates of 32.0% and 32.7% to metaphase (M)-II were observed for oocytes isolated from 2-<3- and 3-<4-mm follicles, respectively, whereas significantly (P< 0.05) more oocytes from 4-<6- and 6-<8-mm follicles reached M-II (67.1% and 79.1% respectively). In conclusion, buffalo oocytes displayed a size-dependent ability to undergo meiotic maturation and we suggest that oocytes from >4-mm follicles should be considered in buffalo in vitro fertilization systems for better results.     

Reduced polyspermic fertilization of porcine oocytes utilizing elevated bicarbonate and reduced calcium concentrations in a single-medium system

The development of efficient systems for in vitro production of porcine embryos has been hampered by a high incidence of polyspermic fertilization. A recently developed single-medium system for porcine in vitro maturation (IVM), IVF and in vitro embryo culture (IVC) (Purdue Porcine Medium; PPM) was modified with elevated bicarbonate (44 mM) and reduced calcium concentrations (1.7 mM) for IVF (PPMfert.2). Oocyte penetration was evaluated after maturation in PPMmat (0.5 mg mL(-1) hyaluronan, 0.6 mM cysteine, 10 ng mL(-1) epidermal growth factor (EGF), 0.1 U mL(-1) porcine LH and FSH, and 1 x Minimal Essential Medium (MEM) vitamins) and fertilization (5 h with 5 x 10(5) sperm mL(-1)) in either PPMfert.2 or mTBM (20 mM Tris, 0.0 mM bicarbonate, 7.5 mM calcium). Embryonic development (cleavage and blastocyst stages) was assessed after culture in PPM1 and PPM2. Although penetration was lower in PPMfert.2 (69.9%) compared with mTBM (83.9%), 48.8% of penetrated oocytes were fertilized normally in PPMfert.2 compared with only 27.8% normal fertilization in mTBM. More oocytes cleaved in PPMfert.2 (77.9% v. 53.7%), but development to the blastocyst stage was not different between treatments (14.1% v. 14.3%). Further work is needed to improve embryonic development, but reduced polyspermic penetration is an important step in the optimization of the PPM system for in vitro porcine embryo production.     

干细胞微环境促进体外培养的卵巢组织内卵泡发育成熟

目的:研究骨髓间充质干细胞(Mesenchymal stem cell,MSC)-软琼脂培养体系对小鼠卵巢组织片中卵泡发育的作用。方法:分离、培养、FACS鉴定小鼠MSC;建立MSC-软琼脂"小岛"培养体系,500μm厚小鼠卵巢组织片嵌入支架上培养。培养液内加入1.5IU/mlPMSG,每2天半量换液1次,放射免疫法动态检测雌二醇(E2)和孕酮(P)含量。第6天加入1.5IU/mlhCG,17h后体视显微镜下获取窦卵泡内颗粒细胞-卵母细胞复合物(cumulus-oocyte complex,COC),体外受精后观察受精率和囊胚形成率。结果:卵巢组织在MSC-软琼脂培养体系中存活良好,卵泡直径、颗粒细胞数量和层数不断增加,E2水平稳定上升。加入hCG17h后,卵泡进一步成熟,有窦腔形成,P水平急剧上升。获取的卵母细胞体外受精率明显低于体内成熟组(62.5%vs89%,P<0.01),但是囊胚形成率两者间比较差异无统计学意义(82.4%vs87.5%,P>0.05)。结论:MSC-软琼脂培养体系有利于卵泡发育、成熟,获得的卵母细胞功能良好。     

Follicle size and oocyte diameter in relation to developmental competence of buffalo oocytes in vitro

Follicular size, oocyte morphology and diameter were investigated for their possible relationship with in vitro developmental competence of buffalo oocytes. Cumulus oocytes complexes (COCs), aspirated from small (<3 mm), medium (3-8 mm) and large (>8 mm) follicles of normal ovaries and cystic ovarian follicles of abattoir-derived ovaries, were graded for their morphological appearance and were cultured to assess their developmental competence. The influence of cystic follicles on maturational competence of COCs recovered from co-existing follicles of cystic ovaries was studied. The mean diameter of oocytes from follicles of different size were examined, and the influence of oocyte diameter--(i) <126 microm; (ii) 127-144 microm; (iii) 145-162 microm; and (iv) >163 microm--on in vitro maturation, cleavage and embryo yield was studied. Results suggested that increased fertilization, cleavage and embryo development were significantly (P<0.05) higher in COCs aspirated from large follicles, followed by medium and small-sized normal follicles, and the presence of cystic follicles had no significant (P<0.05) effect on the maturation competence of the COCs recovered from co-existing follicles. The mean diameter of the buffalo oocyte obtained from normal ovaries was found to be 146.4 microm and the rate of blastocyst production in vitro was significantly higher (P<0.05) in oocytes with diameters greater than 145 microm. In conclusion, the larger the size of the follicles and oocytes, the greater the developmental competence in vitro of buffalo oocytes.     

Effect of centrifugation on early embryonic development and parthenogenetic activation of bovine oocytes matured in vitro

This study examined the fertilization, early developmental competence and capacity for parthenogenetic activation of bovine oocytes matured in vitro after centrifugation. Immature oocytes were cultured in tissue culture medium 199 supplemented with 10% fetal bovine serum and 75 mIU mL(-1) FSH + LH at 5% CO2 to facilitate maturation. After culture for 24 or 30 h, the metaphase-II stage oocytes were centrifuged at 3000, 5000, 7000 or 10000g for 5 min before in vitro fertilization or parthenogenetic activation. Frozen-thawed bull semen was used for in vitro fertilization. For parthenogenetic activation, the oocytes were exposed to 20 microM calcium ionophore A23187 for 5 min at room temperature. Fertilization rates were not different between control and treatment groups (87.7% v. 74.6%, 73.4%, 75.9% and 76.4% respectively). Also, there were no differences in early embryonic development between control and treatment groups (rates of blastocyst formation were 21.1% v 20.2%, 28.8%, 31.2% and 24.1% respectively). When the oocytes were centrifuged at various speeds alone, the activation rate of oocytes was significantly higher (P < 0.05) in the 10000g treatment group compared with control (10.8% v 0.0%). There were no differences in the activation rates of oocytes between control and treatment groups at speeds up to 7000g (70.9% v. 71.9%, 78.3% and 77.2% respectively) after centrifugation and stimulation with Ca(2+)-ionophore. However, the activation rate of oocytes was significantly higher (P < 0.05) in the 10000g treatment group compared with control (70.9% v. 83.1%). In addition, the percentage of activated oocytes with diploid formation was significantly higher in the oocytes after centrifugation at 10000g and stimulation with calcium ionophore A23187 than in the control (18.4% v 7.1%). These results indicate that centrifugation of oocytes matured in vitro has no detrimental effect on fertilization and subsequent early embryonic development. They also indicate that the oocytes might be parthenogenetically activated after centrifugation and that high-speed centrifugation may induce activation of some oocytes. The results suggest that the optimal speed for centrifugation of bovine oocytes might be < or = 7000g to enhance the visibility of nuclear elements for further micromanipulation.     

Effects of Exposure to Heavy Metals on Viability, Maturation, Fertilization, and Embryonic Development of Buffalo (Bubalus bubalis) Oocytes In Vitro

The aim of the present study was to examine the effect of heavy metals, cadmium and lead, on buffalo oocyte viability and in vitro development. Oocytes were aspirated from ovaries of slaughtered buffaloes. Only viable and metabolically active oocytes with more than three layers of cumulus cell layers and homogeneous ooplasm were selected. Effects of nine concentrations (0, 0.005, 0.05, 0.5, 1.0, 1.5, 2.5, 5, and 10 μg/mL) of cadmium or lead on buffalo oocyte viability, morphological abnormities, maturation, and embryonic development in vitro were studied. Oocytes were cultured for 24 h and then checked for viability (0.05% trypan blue staining for 2 min), morphological abnormalities, and reduction assay by MTT test in experiment 1. The doses of cadmium and lead causing 100% oocyte death (1-day culture) were determined (experiment 2). In experiment 3, viable oocytes were matured in vitro in media containing different levels of cadmium or lead and then inseminated in vitro with frozen-thawed spermatozoa, and the resultant cleaved embryos were cultured in a control embryo culture medium for 8 days. In experiment 4, oocytes were cultured in control oocyte maturation medium, then fertilized, and the resultant embryos were cultured in media containing different levels of cadmium or lead for 8 days. The number of cells in the trophectoderm and inner cell mass (ICM) and the total cell counts (TCN) of blastocysts derived by in vitro culture of two- to four-cell-stage embryos (produced in control medium) in media containing 0, 0.005, 0.05, 0.5, and 1.0 μg/mL of cadmium or lead were analyzed by differential staining technique (experiment 5). Cadmium and lead were found to have a dose-dependent effect on viability, morphological abnormities, maturation, cleavage and morula/blastocyst yield, and blastocyst hatching. A significant decline in viability of oocytes was observed at 1.0 mg/mL cadmium or lead compared to the control group. The doses of cadmium and lead causing 100% oocyte death (1-day culture) were 18 and 32 μg/mL, respectively. Cadmium and lead at 1.0 and 2.5 μg/mL, respectively, caused a significant reduction of maturation of oocytes compared to the lower concentrations. No cleavage or morulae/blastocysts were produced when the oocytes/embryos were cultured in media containing 2.5 and 5.0 mg/mL of either cadmium or lead, respectively. Similarly, no morulae/blastocysts were produced from cleaved embryos cultured in media containing 2.5 and 5.0 μg/mL cadmium and lead, respectively. The developmental block, degeneration, and asynchronous divisions were higher in embryos exposed to cadmium than in those exposed to lead. TCN and number of cells in ICM were significantly lower in blastocysts derived from two- to four-cell-stage embryos cultured in media containing heavy metals. In conclusion, cadmium and lead lowered the viability and development of buffalo oocytes but at a concentration higher than that estimated in the body fluids and environment. Cadmium was found to be more ovotoxic than lead.     

OPS法玻璃化冷冻未成熟卵母细胞的效果观察

目的:探讨OPS(open pu lled straw,开放式拉细麦管)法玻璃化冷冻技术冻存未成熟卵母细胞的效果。方法:小鼠GV期卵母细胞用OPS法玻璃化冷冻复苏后行体外成熟培养(in-vitro m aturation,IVM)或直接行IVM,所获成熟卵行体外受精(IVF)和胚胎的体外培养(IVC)。以体内成熟卵行IVF/IVC作为in-vivo对照组。结果:GV期卵冻融后65.11%存活,IVM后成熟率为52.86%,其成熟率显著低于IVM对照组。冻融卵成熟后受精、卵裂率(33.78%、76.00%)低于IVM对照组和in-vivo对照组,培养后未见囊胚形成。结论:OPS法玻璃化冷冻技术可有效冻存GV期卵母细胞,复苏后可发育成熟,但卵的受精和继续发育能力欠佳。     

Timing and regulatory aspects of oocyte maturation in vitro in the tammar wallaby (Macropus eugenii)

Oocytes from a marsupial, the tammar wallaby (Macropus eugenii), resemble those of eutherian mammals in their ability to resume meiosis in vitro when cultured under suitable conditions. Culture for 42-48 h in Eagle's minimum essential medium (EMEM) supplemented with 10% fetal calf serum, and 10 microg mL(-1) porcine luteinizing hormone (pLH) was required in order for oocytes, collected from the large antral follicles (> 2 mm diameter) of tammar wallabies (primed with 6 mg of porcine follicle stimulating hormone twice daily for four days), to proceed to metaphase II (MII) of meiosis. Under these conditions, chromatin condensation was observed within 4-8 h of culture in 61% of oocytes; metaphase I (MI) chromosomes were observed from 18-30 h of culture (66%); and most oocytes (76%) progressed to MII by 42 h in vitro. The addition of cycloheximide, a protein synthesis inhibitor, at concentrations of 1-100 microg mL(-1), prevented maturation of tammar wallaby oocytes in vitro. This effect was reversible, as oocytes washed free of cycloheximide after 4 h of incubation were able to progress to MII. The addition of cycloheximide to wallaby oocytes at MI of meiosis prevented normal progression to MII suggesting that proteins critical for nuclear maturation are synthesized throughout the maturation process. Genistein, a protein kinase inhibitor decreased maturation of wallaby oocytes in a dose dependent manner. However, the concentration required to significantly inhibit maturation of wallaby oocytes (60 microg mL(-1)) was greater than that required for eutherian species. Most wallaby oocytes were able to undergo germinal vesicle breakdown (GVBD) in the presence of high concentrations of genistein but produced abnormal chromatin configurations and were unable to progress to MII. Future studies will examine whether cytoplasmic changes occur in marsupial oocytes in vitro and their temporal relationship to nuclear maturation.     

Development of a porcine follicle-stimulating hormone and porcine luteinizing hormone induced ovulation protocol in the seasonally anoestrus brushtail possum (Trichosurus vulpecula)

Monovulatory brushtail possums (Trichosurus vulpecula) were stimulated with exogenous hormones during seasonal anoestrus to overcome ovarian insensitivity and induce ovulation. Seasonal ovarian insensitivity to pregnant mare serum gonadotrophin (PMSG) was overcome by a new porcine follicle-stimulating hormone/porcine luteinizing hormone (pFSH/pLH) protocol. This protocol was refined because the original treatment produced oocytes with abnormal morphology. Possums (n = 12 per group) received eight injections of pFSH of 1.5, 3.0 or 6.0 mg per injection (at 12-h intervals for 4 consecutive days). Ovulation was induced 12 h after the final pFSH injection with a 4-mg injection of pLH. Control animals were treated with the established protocol of a single injection of 15 IU of PMSG, followed 48 h later with an injection of 4 mg of pLH. All females responded to pFSH/pLH treatment, although optimal stimulation occurred in those receiving 8 x 3 mg pFSH, with 13-14 ovulations and recovery of 11-12 oocytes per female (8 x 1.5 mg pFSH: 13 ovulations, 8-9 oocytes; 8 x 6 mg pFSH: 7-8 ovulations, 4-5 oocytes). In contrast, only seven of 12 females responded to PMSG/pLH and, of those responding, only 2-3 ovulations occurred and only 1-2 oocytes per female were recovered. However, around 80% of oocytes recovered after PMSG/pLH treatment had undergone nuclear maturation (metaphase II/1st polar body) compared with around 60% of oocytes from pFSH/pLH-treated animals. In possums killed from 27 to 39 h after pLH treatment, ovulation onset was first observed from 30 h and by 31.5 h, all animals had completed ovulation. Laparoscopic artificial insemination (LAI) was performed on pFSH/pLH-treated animals to determine whether the oocytes produced were capable of fertilization. Uterine LAI performed 27.5-28.5 h after pLH treatment yielded 11/26 fertilized oocytes (up to 4-cell stage), whereas vaginal LAI performed 13-14 h after pLH treatment yielded 21/53 fertilized oocytes. A proportion of oocytes generated from the refined pFSH/pLH protocol are thus properly mature and capable of fertilization. Further refinement of the protocol is now needed to improve the yield of fully matured oocytes.     

Synchronisation of canine germinal vesicle stage oocytes prior to in vitro maturation alters the kinetics of nuclear progression during subsequent resumption of meiosis

Inhibition of meiosis before in vitro maturation (IVM) can improve meiotic competence in immature mammalian oocytes. Therefore, meiosis-inhibiting agents were evaluated singularly for the ability to arrest and synchronise germinal vesicle (GV) stage canine oocytes, and the most effective treatments were combined to improve meiotic resumption rates. Oocytes cultured in 2 ng mL(-1) oestradiol (E2), 10 IU mL(-1) eCG, or both (EG) for 72 h resulted in significantly fewer oocytes resuming meiosis in EG than the control, E2, or with eCG. Oocytes cultured in 50 or 100 micromol L(-1) of butyrolactone 1 or roscovitine (ROS) for up to 48 h did not resume meiosis nor increase subsequent meiotic resumption rates following IVM. A combination of 50 micromol L(-1) ROS and EG treatment for 48 h significantly increased the proportion of canine oocytes in meiotic arrest. More importantly, following 48 h of IVM, ROS+EG-treated oocytes demonstrated a dramatic increase in the ability to resume meiosis compared with the non-treated controls (51.3 +/- 8.2% and 10.8 +/- 4.5%, respectively; P < 0.05). These data indicate that chemical and biological meiotic inhibitors are effective at inducing GV arrest in canine oocytes. Furthermore, these inhibitors are reversible and beneficial to subsequent meiotic resumption in vitro.     

不同方法冻融小鼠未成熟与成熟卵母细胞的研究

目的:探讨不同冷冻方法对小鼠生殖泡(GV)期与成熟期(MⅡ)卵母细胞体外成熟、体外受精及胚胎发育能力的影响。方法:收集ICR小鼠GV期与MⅡ期卵母细胞,分别行程序化冷冻(慢速冷冻-快速解冻)与玻璃化冷冻。解冻后比较各组成熟率、受精率、卵裂率及8细胞胚胎形成率。结果:采用玻璃化冷冻法冷冻GV期卵母细胞(Ⅰ组),解冻后存活率达84.2%,显著高于MⅡ期卵母细胞(Ⅱ组)60.5%及程序化冷冻组(Ⅲ组)56.9%、(Ⅳ组)55.7%(均P<0.01)。各组成熟率、受精率、卵裂率及8细胞胚胎形成率比较,差异无统计学意义(P>0.05)。结论:在进行卵母细胞冷冻保存时,宜选择玻璃化冷冻法,且GV期卵母细胞冷冻效果好于MⅡ期卵母细胞。     

人未成熟卵玻璃化冷冻初步实验探讨

目的:对人未成熟卵母细胞玻璃化冷存保存技术进行初步实验探讨。方法:采用OPS玻璃化冷冻方法,对未成熟的卵子进行冷冻,解冻后体外成熟培养,ICSI受精,观察胚胎培养情况,并对某些影响因素进行探讨。结果:冷冻了GV期卵62个,M I期卵40个。两期卵细胞复苏后存活率、成熟率、受精率和卵裂率分别为:80.65%、77.50%,52.00%、41.94%,57.69%、61.54%,60.00%、62.50%,两组间比较无统计学差异(P>0.05);采用HTF或G-Mops两种缓冲液配制玻璃化冷冻液冷冻解冻未成熟卵效果无统计学差异(P>0.05);未成熟卵解冻后置于含性激素的TCM199与单纯IVF30中成熟培养效果无统计学差异(P>0.05)。结论:应用OPS玻璃化冷冻方法能够有效冻存未成熟卵母细胞。     

未成熟卵体外成熟技术在卵巢高反应患者IVF-ET中的应用

目的:探讨未成熟卵体外成熟(IVM)技术在卵巢高反应患者体外受精-胚胎移植(IVF-ET)中的应用价值。方法:在IVF-ET促排治疗中,对双卵巢卵泡数过多,有可能发生卵巢过度刺激综合征(OHSS)或继续治疗可能发生重度OHSS的患者,根据其意愿即刻停药,全部取卵改行IVM治疗12个周期(A组)或取部分小卵泡改行IVM治疗,同时保留部分卵泡继续行IVF-ET常规治疗18个周期(B组)。小卵泡体外培养成熟后,通过卵胞浆内单精子注射(ICSI)获得受精卵并行胚胎移植或冷冻。统计分析未成熟卵的成熟率、卵母细胞的受精率、胚胎的发育情况及临床结局。结果:两组30个取卵周期,共获未成熟卵240个,经IVM、ICSI和体外培养后,成熟率、受精率、正常卵裂率及优质胚胎率分别为61.25%(147/240),77.55%(114/147),92.98%(106/114)和29.25%(31/106)。A组8例行IVM新鲜胚胎移植(8周期)4例临床妊娠,A、B两组有8例行IVM解冻胚胎移植(9周期)3例临床妊娠,已有3例分娩。A组12例无OHSS发生,促性腺激素用量少于B组,B组18例中3例有OHSS风险而取消胚胎移植。结论:对常规IVF促排周期中卵巢高反应患者及时改行IVM,可以避免周期取消及OHSS的发生,减少促排卵药物的使用量,同时获得较好的临床妊娠率。     

Ovulation in the tree shrew (Tupaia belangeri) induced by gonadotrophins

The induction of ovulation by exogenous gonadotrophins is an important approach for recovering oocytes used for studies on the reproductive biology of some mammals. In the present study, pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (hCG) were used to induce ovulation in the tree shrew (Tupaia belangeri) using the following regimens. Groups A1-A3, multiple injections of PMSG (30-60 IU) followed by a single dose of hCG (30-60 IU); B1, combination of a single injection of PMSG (60 IU) with a single dose of hCG (60 IU); E1, combination of a single injection of PMSG (60 IU) with a single dose of hCG (30 IU) plus PMSG (30 IU); and administration of either PMSG (C1 and C2) or hCG (D1). The ovulation rate of animals producing oocytes with either first polar body or distinct perivitelline space, and the mean number of oocytes per animal were considered the most important criteria in each regimen. The most effective induction of ovulation was achieved in groups B1 and E1, with ovulation rates of 4/4 and 4/4, respectively, and mean numbers of ovulated oocytes per animal of 3.25 +/- 0.48 and 4.00 +/- 0.71 respectively. No ovulation was observed in the control group or in group D1. Therefore, regimes B1 and E1 were considered as the simplest and most effective for the induction of ovulation in the tree shrew.     

BDNF对小鼠卵母细胞体外成熟及发育能力的影响

目的:观察脑源性神经营养因子(BDNF)对小鼠未成熟卵的体外成熟及发育能力的影响。方法:以α-MEM为基础培养液,添加不同浓度(0、1、5、10 ng/ml)的BDNF以及FSH、FBS培养小鼠未成熟卵,并进行体外受精,观察卵母细胞成熟率、受精率和胚胎发育至囊胚的能力,了解不同培养条件下BDNF对卵母细胞发育能力的影响。结果:当体外成熟培养液中含有FSH和10%的FBS时,与体外成熟对照组比较,BDNF虽然不影响卵母细胞的成熟率和受精率,但BDNF 5 ng/ml组的囊胚形成率(75.00%)显著高于体外成熟对照组(56.63%),而接近体内成熟组(76.92%);当培养液中仅含FBS时,各组间卵母细胞成熟率和受精率没有差异,但与对照组比较,BDNF显著提高囊胚形成率;当培养液中不含FBS、FSH时,虽然无囊胚形成,但BDNF显著提高了卵母细胞的受精率。结论:BDNF能促进小鼠未成熟卵胞质的发育,提高卵母细胞的发育能力。     

添加两种不同培养成分对人未成熟卵体外成熟培养的影响

目的:研究添加两种不同培养成分对人未成熟卵母细胞体外成熟培养(IVM)的效果。方法:选择接受ICSI治疗的77名不孕患者共收集未成熟卵177枚,随机分A组(激素组)33例,添加0.075 IU/ml FSH及0.075 IU/ml LH至基础IVM培养液中;B组(成熟卵泡液组)44例,50%基础IVM培养液与50%人成熟卵泡液配成。将两组收集的未成熟卵母细胞放入不同培养液中培养48 h,每24 h倒置显微镜下观察卵母细胞的形态;对MII卵进行ICSI,ICSI操作后继续培养,ICSI后16～20 h进行受精观察,24及48 h分别进行卵裂观察及胚胎评分。结果:①B组未成熟卵母细胞48 h成熟率和MI期卵母细胞48 h成熟率显著高于A组,差异有统计学意义(P<0.05),两组培养液GV期卵母细胞24和48 h成熟率比较差异无统计学意义(P>0.05)。②B组2PN卵裂率显著高于A组,差异有统计学意义(P<0.05),两组2PN受精率及可利用胚胎率差异无统计学意义(P>0.05)。结论:人成熟卵泡液内可能含有一些未知的有利于卵母细胞成熟的因子,深入研究卵泡液的成分,进一步明确其促卵母细胞成熟机制对开发新的IVM培养液、改善IVM的临床结局有重要意义。     

体外受精/胞浆内单精子注射中异常受精的影响因素分析

目的：探讨体外受精（IVF）和胞浆内单精子注射（ICSI）后单原核和多原核受精卵生成的影响因素,为降低异常受精率探寻可行的方法。方法：选取2013年9月—2014年2月本中心2 229个周期[1 425个IVF周期和804个ICSI周期],共计25 160个卵细胞的临床资料,探讨其IVF和ICSI后异常受精的影响因素。结果：①IVF中单原核受精卵生成率与不孕类型、促性腺激素（Gn）剂量及使用时间无关,但IVF周期中女方年龄＞38岁组单原核受精卵生成率显著高于31～38岁组;②常规IVF周期中多原核受精卵生成率显著高于ICSI组;IVF周期中,当获卵数＞15个、取卵日血清雌二醇（E2）水平＞2 000 pg/mL及人绒毛膜促性腺激素（hCG）日E2水平与取卵日E2差值＞4 000 pg/mL者≥3个原核（3PN）形成率显著升高;ICSI周期中,随着女方年龄的增高,特别是女性大于31岁后多原核受精卵生成率显著增高;③采用多重线性回归分析,ICSI受精组中异常原核受精卵数与女方基础（月经周期第2～3天）的E2及黄体生成激素（LH）值、获卵总数呈线性相关,IVF组中异常原核受精卵数与基础（月经周期第2～3天）FSH及获卵总数呈线性关系,IVF组和ICSI组异常原核受精卵数与hCG注射日孕酮（P）/E2×1 000呈反向线性关系。结论：IVF/ICSI中异常受精生成的机制和影响因素不尽相同,临床工作中要针对不同不孕人群选择合适的受精方式,并在促排卵过程根据患者内分泌及卵泡数的变化情况及时更改用药剂量,有助于降低异常受精率。     

In vitro maturation and in vitro fertilization of bovine oocytes cultured in a chemically defined, protein-free medium: effects of carbohydrates and amino acids

This study was conducted to examine the effects of carbohydrates and amino acids on the maturation and fertilization of bovine oocytes. To evaluate the effect of each treatment without any unpredictable interference, oocytes were cultured in a simply defined medium (modified Tyrode's medium; mT) without the addition of hormones and proteins. In Experiment 1, oocyte maturation to the metaphase-II stage was significantly (P<0.0001) enhanced after the addition of glucose (5.6 mM), lactate (10 mM) and/or pyruvate (0.5 mM) to mT (37-74%) than after no addition (0%). In mT supplemented with glucose, the addition of 19 essential and non-essential amino acids (aa; 0, 0.01, 0.1, 1, 5 or 10%) did not further improve in vitro maturation (Experiment 2) or in vitro fertilization (Experiment 3) of oocytes. However, more (P<0.05) pronuclear formation after in vitro-insemination was found in oocytes matured in mT with 1% aa and glucose than in oocytes matured in mT with glucose alone (56% vs. 35%). Penetration of spermatozoa into the ooplasm was initiated at 3 h after insemination and pronuclear formation from 8 h (Experiment 4). When cultured inseminated oocytes were examined up to 192 h post insemination, a significant (P<0.05) increase in the number of 2-cell (18 v. 38%) and 8-cell embryos, (7 v. 20%) and morulae (0 v. 8%) was found after the addition of 1% aa to mT with glucose than after no addition (Experiment 5). A limited number of oocytes matured in mT with aa and glucose developed to the blastocyst stage (6%). These results indicate that exogenous carbohydrates and amino acids are prerequisites for the maturation and fertilization of bovine oocytes in vitro. Glucose alone promotes the nuclear maturation of oocytes, whereas amino acids aid the pronuclear formation of fertilized oocytes.     

锰对小鼠卵母细胞成熟和体外受精的影响

目的　研究锰的生殖毒性。方法　采用小鼠卵母细胞体外培养、体外受精的方法研究了硫酸锰对小鼠卵母细胞成熟和受精能力的影响。结果　硫酸锰可以抑制卵母细胞第一极体的释放 ,降低小鼠平均超排卵的卵母细胞数和卵母细胞的存活率和体外受精率。对小鼠体内生发泡破裂 (GVBD)没有影响 ,但可以抑制体外培养卵母细胞的GVBD ;硫酸锰还可以抑制受精卵的卵裂。结论　本实验结果提示 ,硫酸锰可以破坏卵母细胞的成熟 ,降低卵母细胞的受精能力 ,具有明显的生殖毒性