体内成熟与体外成熟的卵母细胞纺锤体位置及其与胚胎发育的关系

目的研究体内成熟与体外成熟卵母细胞的纺锤体位置及其与胚胎发育的关系。方法对134个体内成熟卵母细胞在卵母细胞胞质内单精子注射法（ICSI）操作时用纺锤体实时观察仪进行纺锤体位置的观察,体内成熟卵母细胞来自单纯因男性不育而进行ICSI治疗的患者15例（体内成熟组）。另外对45个体外成熟的卵母细胞观察纺锤体位置,体外成熟卵母细胞来自因多囊卵巢综合征致不孕而进行治疗的患者5例（体外成熟组）。纺锤体的位置按照其与第一极体之间的角度不同分为Ⅰ、Ⅱ、Ⅲ、Ⅳ和Ⅴ级。并观察两组成熟卵母细胞的受精及其胚胎发育情况。结果体内成熟组和体外成熟组患者的卵母细胞中可观察到纺锤体的分别占83．6％（112／134）和82．2％（37／45）。体内成熟组患者卵母细胞纺锤体的位置Ⅰ、Ⅱ、Ⅲ、Ⅳ和Ⅴ级分别为22．4％、55．2％、3．O％、3．O％、16．4％,体外成熟组则分别为17．8％、51．1％、8．9％、4．4％、17．8％,两组各级间分别比较,差异均无统计学意义（P〉0．05）。在体内成熟组卵母细胞中,纺锤体离第一极体较近（Ⅰ级）者受精率较高（93．3％）,显著高于其他各级（分别为73．0％、2／4、1／4、63．6％,P〈0．05）。结论体内成熟与体外成熟卵母细胞间纺锤体位置未见显著差异;纺锤体的位置与卵母细胞受精率有一定相关性。     

人类不同时期未成熟卵母细胞玻璃化冷冻后发育潜能的比较

目的:探索未成熟卵子的最佳冷冻时期。方法:收集卵胞质内单精子显微注射-胚胎移植(ICSI-ET)周期中未成熟的卵母细胞,按其成熟度分为生发泡期(GV组)卵子179枚和第一次减数分裂中期(MI组)卵子323枚,所有卵子均经玻璃化冷冻,解冻后行体外成熟(IVM)培养,ICSI受精,观察比较GV组和MI组解冻后存活、体外成熟、受精及胚胎发育情况。结果:GV组复苏存活率显著高于MI组(83.24%vs 75.54%,P=0.045),MI组体外成熟率、受精率、卵裂率、优质胚胎率均略均高于GV组,但无统计学差异(P0.05),MI组可利用胚胎率显著高于GV组(78.67%vs 60.53%,P=0.041)。结论:超促排卵周期中未成熟卵母细胞先玻璃化冷冻保存,再行体外培养是可行的。GV期卵母细胞复苏存活率高于MI期卵母细胞,但MI期卵母细胞冻融后发育潜能优于GV组卵母细胞。     

冻融体外受精-胚胎移植周期人未成熟卵母细胞的体外成熟及纺锤体结局

目的:探讨冻融的不同状态人未成熟卵母细胞体外成熟后纺锤体状态与受精率的关系。方法:随机收集本中心108个体外受精-胚胎移植周期(IVF)中183枚不同状态废气的成熟卵母细胞,分为:卵丘-卵母细胞复合物组,48枚;裸卵组,135枚,其中第一次减数分裂中期(MI)65枚,生发泡期(GV)70枚。玻璃化冷冻保存,经解冻、体外培养成熟后,应用Polscope成像系统观察纺锤体,然后行卵胞浆内单精子显微注射受精,记录各指标情况。结果:①卵丘-卵母细胞复合物组与裸卵组的存活率、体外成熟率、纺锤体出现率、受精率比较,均无统计学差异(P>0.05);②GV组的存活率显著高于MI组(P<0.05),而前者的体外成熟率显著低于后者(P<0.05);③各组体外成熟后有纺锤体出现的卵母细胞受精率均显著高于无纺锤体组(P<0.05,P<0.01)。结论:冻融IVF周期不同状态的人未成熟卵母细胞都有一定发育潜能;有纺锤体出现的冻融人未成熟卵母细胞质量较高。     

冻融液的温度对人卵母细胞玻璃化冻融效果的影响

目的:探讨冻融液的操作温度对成熟阶段(MII)人卵母细胞的玻璃化冻融效果的影响.方法:收集体外受精-胚胎移植(IVF-ET)患者中受精失败的成熟卵母细胞,根据放置在冻融液操作温度的不同分为A组、B组、C组.解冻后存活卵母细胞及对照组(未冷冻组,D组)卵母细胞固定后进行免疫荧光染色.然后用Nikon CISI激光扫描共聚焦显微镜观察纺锤体、染色体形态.结果:A组与对照组卵的纺锤体和染色体形态正常率分别为13.0%和13.0%、18.2%和18.2%,相互比较差异均无统计学意义(P＞0.05);A组与对照组卵的纺锤体缺失率(Ⅳ型)为65.2%与39.4%,相互比较差异无统计学意叉(P＞0.05);B组卵的染色体形态正常率及C组卵的纺锤体和染色体形态正常率均为0,与对照组比较差异均有统计学意义(P＜0.05);B、C组卵的纺锤体缺失率(Ⅳ型)为78.2%、90.0%,与对照组比较差异有高度统计学意义(P＜0.01).结论:降温前放置在冷冻液的合适操作温度可以减少冻融对卵子纺锤体和染色体的损伤程度.     

多囊卵巢综合征妇女体外成熟卵母细胞胚胎慢速冷冻复苏移植结局分析

目的评价未成熟卵母细胞体外成熟（IVM）后形成的卵裂期胚胎经慢速冷冻一解冻后的发育能力。方法将2006年1月至2010年12月北京大学第三医院因多囊卵巢综合征（PCOS）合并不孕症行卵裂期胚胎复苏移植的385例患者分为两组：复苏胚胎来源于体外成熟的卵母细胞组（IVM组,46例）和复苏胚胎来源于常规体内成熟的卵母细胞组（IVF组,339例）。采用慢冻速溶法解冻移植后比较两组患者的临床结局。结果IVM组复苏胚胎243枚,复苏后存活162枚,复苏率为66．67％;IVF组复苏胚胎1605枚,复苏后存活1082枚,复苏率为67．41％,两组比较,差异无统计学意义（P〉0．05）。IVM组患者的临床妊娠率和着床率分别为19．30％（11／57）和10．61％（14／132）,明显低于IvF组临床妊娠率（45．45％,175／385）和着床率（26．14％,240／918;P均〈O．05）。结论体外成熟卵母细胞发育形成的卵裂期胚胎慢速冷冻后临床结局欠佳,可能与冻融前胚胎自身的发育潜力有关。     

不同冷冻方法对小鼠不同成熟时期卵母细胞纺锤体的影响

目的:探讨不同冷冻方法对小鼠成熟期(MⅡ期)及生发泡期(GV期)卵母细胞的纺锤体及胚胎发育的影响。方法:收集GV期和有纺锤体的MⅡ期小鼠卵母细胞,随机分为3组:慢速冷冻-快速复温组、超高速玻璃化冷冻组和对照组(未冷冻组)。Polscope观察解冻0、3、6h后存活的MⅡ期及体外培养成熟GV期卵母细胞的纺锤体,有明显纺锤体的行卵胞浆内单精子显微注射受精,评价胚胎发育。结果:(1)超高速玻璃化GV组的存活率、卵裂率均显著高于慢冻GV组(P<0.05);(2)两冷冻MⅡ组解冻后0、3及6h纺锤体出现率和优质胚胎率均显著低于对照MⅡ组(P<0.05);(3)超高速玻璃化GV组体外成熟后纺锤体的出现率、优质胚胎率均显著高于超高速玻璃化MⅡ组(P<0.05)。结论:慢速冷冻-快速复温法对小鼠不同成熟时期卵母细胞的纺锤体损伤较大;超高速玻璃化冷冻对小鼠生发泡期卵母细胞纺锤体的影响则较小,是一种简便、快捷、高效的冷冻方法。     

抗氧化剂抗坏血酸对小鼠卵母细胞体外成熟和发育的影响

目的:探讨抗氧化剂抗坏血酸(ascorbic acid,AA)对小鼠卵母细胞体外成熟和发育的影响。方法:本实验采用4种不同浓度的AA加入M_2基础培养液中,即0 mg/L、25 mg/L、50 mg/L、100 mg/L。体外培养小鼠未成熟卵母细胞14~16 h,观察各组间卵母细胞体外成熟率、线粒体分布、纺锤体形态和DNA损伤等4个相关指标。结果:当AA浓度为50 mg/L时,随着AA浓度的升高,未成熟卵母细胞体外成熟率逐渐升高,但差异无统计学意义(P0.05);而线粒体异常分布比率、异常纺锤体数和DNA损伤卵母细胞数逐渐降低,以50 mg/L组最为显著,差异有统计学意义(P0.05);而100 mg/L与0 mg/L组相比,差异无统计学意义(P0.05)。结论:在小鼠体外成熟培养基中添加适宜浓度的AA可提高卵母细胞体外成熟和后期的发育。     

人类未成熟卵母细胞玻璃化冷冻研究

目的:探讨玻璃化冷冻未成熟卵母细胞的有效性。方法:根据有无颗粒细胞将实施玻璃化冷冻的GV期卵母细胞分为含颗粒细胞(非裸卵)组和不含颗粒细胞(裸卵)组;将部分GV期卵母细胞体外培养至MⅡ期卵母细胞实施玻璃化冷冻,比较非冷冻IVM组与MⅡ卵玻璃化冷冻组间、裸卵组与非裸卵组间的存活率、成熟率、受精率、卵裂率及囊胚形成率。结果:非裸卵组的成熟率大于裸卵组(P<0.05),而存活率、受精率、2-细胞形成率、>2-细胞形成率之间均无统计学差异(P>0.05)。另外,非冷冻IVM组与GV玻化组间成熟率、受精率、卵裂率均存在显著性差异(P<0.05);非冷冻IVM组与MⅡ期卵玻化组间成熟率、受精率、卵裂率间均存在统计学差异(P<0.05);GV玻化组与MⅡ玻化组间存活率、成熟率、受精率、卵裂率间均无统计学差异(P>0.05)。结论:玻璃化冷冻未成熟卵母细胞需要保留颗粒细胞,同时初步构建了人GV期卵的玻璃化冷冻联合IVM技术的雏形。     

表皮生长因子卵丘细胞对卵母细胞体外成熟的影响

目的：探讨表皮生长因子（EGF）、卵丘细胞人类生殖泡（germinal vesicle ,GV)期不成熟卵母细胞体外成熟的影响，方法：将EGF和促性激素（gonadotropin,Gn）联合应用于不成熟卵母细胞的体外培养，并同单纯应用Gn相对照观察EGF的影响。同时将卵母细胞分为卵丘卵母细胞复合物（CEO组）及裸卵（DO组）进行培养，了解卵丘细胞在体外培养中的作用。结果：EGF可以提高DO组的MⅡ期率（P＜0．01），对于CEO组应用EGF后可以促进胞质的成熟，提高受精能力（P＜0．05）。关于卵丘细胞的作用，CEO组的MⅡ期率为68．8％，明显高于DO组的46．7％（P＜0．01），CEO组的卵裂率为72．7％，高于DO组的35．7％（P＜0．05）。结论：EGF可以直接促进不成熟裸卵体外成熟，提高其MⅡ期率，与Gn联合应用后可进一步促进卵丘卵母细胞复合物胞质的成熟，提高受精率，保留卵丘细胞利于卵母细胞质的发育，提高不成熟卵母细胞的体外成熟能力，使MⅡ期率，卵裂率升高。     

人类成熟卵母细胞慢速程序化冷冻复苏后培养时间对纺锤体和染色体的影响

目的 研究慢速程序化冷冻人类成熟卵母细胞复苏后培养时间对纺锤体和染色体的影响.方法 慢速程序化冷冻人成熟卵母细胞102枚,选择复苏后外观存活良好的卵母细胞共64枚,随机分为A组20枚、B组22枚、C组22枚,分别培养不同时间(1、3、5 h)后进行固定、荧光染色;另取新鲜成熟卵母细胞18枚固定、染色作为对照组,采用激光共聚焦显微技术,观察并分析纺锤体和染色体的形态学变化.结果 (1)A、B、C 3组正常纺锤体比例分别为10%(2/20)、46%(10/22)、41%(9/22),均明显低于对照组(83%,15/18),差异均有统计学意义(P＜0.05);A组分别和B组、C组比较,差异也有统计学意义(P＜0.05).纺锤体缺失率A组为45%(9/20),明显高于对照组(6%,1/18),差异有统计学意义(P＜0.01);A组分别和B组(14%,3/20)、C组(14%,3/20)比较,差异也有统计学意义(P＜0.05);B、C组之间比较,差异无统计学意义(P＞0.05).(2)A组正常染色体比例为30%(6/20),与B组(68%,15/22)、C组(64%,14/22)和对照组(78%,14/18)比较均明显降低,差异均有统计学意义(P＜0.05);B、C、对照组之间两两比较,差异均无统计学意义(P＞0.05).结论 慢速程序化冷冻复苏后培养3～5 h可以促进部分卵母细胞纺锤体和染色体形态的恢复.     

Numerical chromosome anomalies after fertilization of freeze-thawed mouse oocytes

Summary The chromosome complement of first cleavage stage mouse embryos was analyzed to investigate the effect of slow freezing-fast thawing cryopreservation on chromosome numbers by comparing these numbers with those found fresh after fertilization of control oocytes. Fewer frozen-thawed (34.1%) than control oocytes (75.0%) cleaved to the 2-cell stage after in vitro fertilization. The incidence of hyperploidy was significantly increased by freezing (4.5% vs. 0% in controls). Polyploidy was not significantly affected (17.0% for freeze-thaw embryos vs. 26.2% for controls).     

Cryopreserved Immature Mouse Oocytes: A Chromosomal and Spindle Study

Purpose: Cryopreservation of human oocytes might provide an alternative approach to freezing supernumerary embryos obtained during IVF. This process, performed on immature denuded prophase I mouse oocytes, was investigated. Methods: We first investigated the capacity of frozen, immature, murine oocytes to continue in vitro maturation after thawing. We then evaluated the risk to offspring from chromosomal damage by cytogenetical and cytological (spindle) analysis. Finally, we attempted to determine the reasons for and the stage of maturation failure. Results: A total of 700 immature oocytes was frozen, 629 (90%) were recovered intact after thawing, and 53% extruded the first polar body, versus 74% for the control group. Freezing was not accompanied by an increase in aneuploidy in maturing oocytes (18 and 15% for thawed and control oocytes, respectively). Consequently, the first meiotic division occurred normally, without an increase in nondisjunction. Spindle analysis demonstrated only a few abnormalities (15 and 2% for thawed and control oocytes, respectively) incompatible with further development. Oocytes arrested during in vitro maturation were mainly at the metaphase I stage (64 and 76% for thawed and control oocytes, respectively). Whereas 17% of thawed oocytes were blocked before the formation of the first meiotic spindle, this never occurred in the control group. Conclusions: Immature murine oocytes can withstand cryopreservation, which is encouraging for future human application of this technique.     

Effects of cryopreservation on the meiotic spindle of human oocytes

The microtubular meiotic spindle of most mammals, including humans, is very sensitive to cooling [Hum. Reprod. 16 (2001) 2374; Fertil. Steril. 54 (1990) 102; Fertil. Steril. 75 (2001) 769; Zygote 3 (1995) 357] and is rapidly depolymerised even after a slight reduction in temperature to 33 degrees C. Spindle disassembly is dependent on the extent of temperature decrease and its duration. After rewarming, the recovery is far from complete. Cryoprotectants themselves may alter the spindle structure, depending on the duration and temperature of exposure, the duration of recovery at 37 degrees C and the species [Hum. Reprod. Update 2 (1996) 193]. Damage to the meiotic spindle is considered to be the cause of aneuploid embryos, by inducing chromatid non-disjunction and chromosome scattering and by disturbing the sequence of events leading to the completion of meiosis and fertilisation. Nevertheless, a consensus arose from all the studies: appropriate exposure to cryoprotectants and appropriate rates of cooling and thawing allow the cryopreservation of mature oocytes without any significant changes in their second meiotic spindle organisation and without any increase in the rate of aneuploid embryos [Mol. Hum. Reprod. 2 (1996) 445; Hum. Reprod. 8 (1993) 1101; Hum. Reprod. 9 (1994) 684; Microsc. Res. Technol. 27 (1994) 165; Fertil. Steril. 75 (2001) 354]. These fundamental studies in humans, showing good preservation of cell structures after freeze-thaw procedures opened the way to new successful clinical trials with embryos derived from cryopreserved mature oocytes [Fertil. Steril. 68 (1997) 724]. Considering immature oocyte freezing at prophase I (germinal vesicle (GV) stage), a stage which was thought to be less sensitive to cryoinjury, pooled data from the literature showed no advantage in terms of survival rates, fertilisation rates of in vitro matured oocytes and developmental ability of the resulting embryos, especially in unstimulated cycles. Moreover, conflicting results are reported on the effects of freezing on the spindle-chromosome configuration of immature oocytes or in vitro matured oocytes, highlighting the need for large scale studies [Hum. Reprod. 10 (1995) 1816; Hum. Reprod. 13 (Suppl. 3) (1998) 161; Hum. Reprod. 17 (2002) 1885; Microsc. Res. Technol. 27 (1994) 165; Fertil. Steril. 68 (1997) 920]. One child has been born after the use of cryopreserved immature oocytes at GV stage, matured in vitro and fertilised by ICSI [Hum. Reprod. 13 (1998) 3156], demonstrating at least the feasibility of this technique. Improvements are required so as to make mature and immature oocyte cryopreservation an established and safe technique for ART.     

超排卵周期未成熟卵体外培养的研究

目的:研究来源于超排卵周期中的未成熟卵在拆除卵丘细胞后进行体外成熟培养(IVM)的成熟、受精及胚胎发育能力,探讨IVM技术的临床应用。方法:选取46名体外受精/卵胞浆内单精子显微注射-胚胎移植(IVF/ICSI-ET)患者为研究对象,比较MI和GV期不成熟卵的体外成熟情况,并比较体内成熟卵和体外成熟卵进行ICSI后的正常受精、异常受精、卵裂和优质胚胎形成情况。结果:体外培养中69.8%的MI期卵和77.2%的GV期卵均在24小时内达到成熟,其24小时和48小时的成熟率、总成熟率均无明显差异(P>0.05)。体外成熟卵与体内成熟卵相比较,正常受精率、异常受精率和卵裂率均无明显差异(P>0.05),优质胚胎形成率较低,差异有显著性(P<0.05)。结论:常规超排卵周期中的未成熟卵在拆除卵丘细胞后能够继续体外发育成熟,具有与体内成熟卵相似的ICSI受精、卵裂能力。虽然优质胚胎的形成率低于体内成熟卵,但增加了可移植胚胎和冷冻胚胎数量,提高了助孕成功率。     

Slow and ultrarapid freezing of fully grown germinal vesicle-stage mouse oocytes: Optimization of survival rate outweighed by defective blastocyst formation

Purpose The cryopreservation of mature metaphase II-stage mouse oocytes is associated with decreased fertilizability, spindle damage, and increased polyploidy. Therefore, we investigated the outcome of cryopreservation of immature germinal vesicle-stage mouse oocytes.Methods Oocytes were punctured from Graafian follicles in primed F₁ hybrid mice and were then released into maturation medium containing the meiotic inhibitor dibutyryl cyclic AMP. Both slow and ultrarapid freezing protocols with dimethyl sulfoxide, 1,2-proponediol, or a mixture of both agents were tested. We recorded morphological survival rates, in vitro maturation rates, and two-cell and blastocyst formation rates. Each group of frozen oocytes was compared with both unfrozen germinal vesicle-stage oocytes and metaphase II-stage oocytes.Results An optimal cryosurvival rate of 78% was reached after ultrarapid freezing with 3 Mdimethyl sulfoxide followed by one-step dilution, but a decreased rate of twocell formation was observed. Freezing with a combination of dimethyl sulfoxide and 1,2-propanediol did not improve this fertilization-decreasing effect. Very low cryosurvival rates after freezing with 1,2-propanediol indicated its inappropriateness for ultrarapid freezing of immature oocytes. The rates of in vitro maturation were equivalent for frozen-thawed and freshly collected germinal vesicle-stage oocytes, independent of the freezing protocol used. We report, nevertheless, as a general characteristic for both slow and ultrarapid freezing of fully grown germinal vesicle-stage oocytes, that the in vitro development up to the blastocyst stage is inhibited despite full nuclear maturation. Conclusion We report that cryopreservation of immature germinal vesicle-stage oocytes is invariably associated with a low developmental capacity after fertilization. The rate of in vitro nuclear maturation did not equate with developmental competence. This in turn suggests the importance of cytoplasmic maturation for embryonic development.     

A PolScope evaluation of meiotic spindle dynamics in frozen–thawed oocytes

In mature human oocytes, the metaphase II (MII) spindle presence and birefringence signal detected through the PolScope may vary before and after freezing. In particular, spindle dynamics during the first few hours after thawing is still under study. In this study, oocytes from stimulated ovaries were cryopreserved in 1.5 mol/l 1,2-propanediol with 0.3 mol/l sucrose using a slow freezing–rapid thawing method. Oocytes were examined with the PolScope for the presence, intensity of signal birefringence and size of the meiotic spindle before freezing and at 0, 1 and 2 h post-thaw (where 0 h = the time of the end of the thawing procedure). Of the 173 surviving oocytes exhibiting a spindle before freezing, 82.7% (143/173) showed spindle birefringence within 1 h of thawing. However, at the end of the thawing procedure the intensity of spindle birefringence (retardance) and the spindle length were smaller in comparison to the pre-freezing condition. These parameters increased after 1 h, although were not restored to the values observed before freezing. No significant changes were observed by extending the culture to 2 h.     

Congélation lente et vitrification des ovocytes humains matures et immatures

Performance and security questions in human oocyte cryopreservation have been taking researchers for about two decades. Oocytes are usually frozen at metaphase II. Immature oocytes cryopreservation is still a research alternative. Two techniques are currently available for oocyte cryopreservation: slow freezing and vitrification. Experimental data suggest that vitrification has less impact on oocyte physiology than classical slow freezing. After slow freezing of mature oocytes, survival and fertilization rates reach 70 to 80% whereas cleavage rates are around 90%, leading to five implantations and 1.2 births per 100 thawed oocytes. After vitrification of mature oocytes, survival and cleavage rates reach 90% leading to 11 implantations and 1.8 births per 100 thawed oocytes. The obstetrical and neonatal prognosis of these pregnancies is reassuring. No increased risk of congenital anomalies has been observed. However, further evaluation is needed to guarantee the safety of cryopreservation procedures. Immature oocyte cryopreservation is not currently perfected but some indications appear of great interest.     

In vitro maturation of human preovulatory oocytes reconstructed by germinal vesicle transfer

OBJECTIVE: To describe a micromanipulation-electrofusion procedure for transferring germinal vesicles (GVs) between immature human oocytes. DESIGN: Pilot study to assess oocyte maturation after an invasive micromanipulation procedure. SETTING: Research laboratory at a university medical center. PATIENT(S): Immature oocytes were discarded from intracytoplasmic sperm injection (ICSI)-IVF cycles of patients 23-48 years of age. INTERVENTION(S): Initially, GV removal and transfer were performed on the same oocyte; these "self-reconstructed" oocytes were then cultured in vitro for up to 50 hours and examined periodically for maturation as judged by the extrusion of the first polar body. In a second study, GVs from oocytes of "old" patients (>38 years old) were successfully transferred into enucleated immature oocytes of "young" patients (<31 years old). MAIN OUTCOME MEASURE(S): Extrusion of the first polar body was monitored in "reconstructed" and control oocytes; karyotypes also were analyzed at meiosis II. RESULT(S): From 48 oocytes from old patients, 12 GVs were successfully removed, transferred, and fused into previously enucleated oocytes from young patients. After in vitro culture, 7 of these "reconstructed" oocytes matured to meiosis II, a maturation rate not significantly different from that observed in nonmanipulated controls. A normal, second meiotic metaphase chromosome complement was observed in 4 of 5 reconstructed oocytes. CONCLUSION(S): Normal meiosis can occur after the transfer of a GV into an enucleated host oocyte. Germinal vesicle transfer may be a valuable research procedure that generates cell models to characterize the cytoplasmic-nuclear interplay for cell cycle regulation, maturation, and fertilization in the human oocyte; it also may be a potentially attractive alternative to oocyte donation.