废弃胚胎继续囊胚培养研究

目的:探讨体外受精治疗周期中废弃胚胎的体外发育潜能。方法:通过囊胚序贯培养法将无原核(0PN)、单个原核(1PN)、多个原核(≥3PN)和卵裂期发育延缓的2原核(2PN)废弃胚胎培养至囊胚期。比较不同来源胚胎囊胚形成情况和d3胚胎的卵裂球数、质量分级等;并利用废弃胚胎囊胚形成情况对体外受精妊娠结局进行预测。结果:共收集801个废弃胚胎,经序贯培养,形成209个囊胚(26.09%),其中58个为优质囊胚(27.75%)。1PN胚胎、0PN胚胎、d3卵裂球数为7-9-细胞胚胎、d3评分为Ⅰ-Ⅱ级胚胎以及卵裂球数为偶数的胚胎囊胚形成率较高(P均<0.05)。废弃胚胎中有囊胚形成者的临床妊娠率明显高于无囊胚形成者(P<0.05)。结论:废弃胚胎有不同程度的发育潜能,部分可发育为囊胚;特别是:①0PN和1PN胚胎;②d3的4-9-细胞胚胎,偶数卵裂球者更佳;③I级和Ⅱ级胚胎。     

Ⅱ、Ⅲ级胚胎活检后体外发育能力的研究

目的:探讨形态学评价质量较差的胚胎有无活检价值,活检后能否正常发育。方法: 160个IVF和ICSI周期剩余的Ⅱ级、Ⅲ级胚胎,来自同一例患者分级相同的胚胎配对,随机分为实验组和对照组。实验组采用喷酸透明带打孔法取出1个卵裂球,对照组继续培养,对比两组囊胚的形成率、孵化率、囊胚细胞总数,并观察不同形态学特征的胚胎活检后的发育情况。结果:活检组胚胎囊胚形成率,囊胚总细胞数与对照组相比没有差别,但囊胚第6天孵出率活检组明显高于对照组;Ⅲ级胚胎活检后囊胚形成率、第6天孵化率、囊胚总细胞数均明显低于Ⅱ级胚胎;活检前细胞数少于7个的胚胎,活检后发育能力显著降低。结论:活检不影响胚胎体外继续发育的能力;Ⅱ级胚胎活检后具有较好的发育潜力,Ⅲ级胚胎活检后囊胚形成率较低,即使形成囊胚,细胞数也较少,不能正常发育;第3天活检时具有7个或7个以上卵裂球的胚胎具有较好的继续发育能力。     

人废弃胚胎单卵裂球体外发育潜能研究

目的:探讨体外受精治疗周期废弃胚胎来源的单卵裂球体外发育潜能。方法:收集21例患者授精培养后第3日不适于移植和冷冻的废弃胚胎共60枚,其中2-细胞期胚胎10枚,3-细胞期胚胎8枚,4-细胞期胚胎26枚,5-细胞期胚胎12枚,6-细胞期胚胎4枚。采用化学法去除透明带并分割胚胎获得单卵裂球,继续体外培养,每24h观察卵裂球发育情况。结果:60枚胚胎共获得229枚单卵裂球。以分割取得单卵裂球日作为第1日(d1),继续培养,其发育似乎遵循d2分裂、d3紧密化、d4出现囊胚腔、d5扩张,延续分割前的程序,但提前进入紧密化期,致使囊胚细胞数少,囊胚期体积亦比正常胚胎小。其中,4-细胞期废弃胚胎来源的卵裂球分裂率、紧密化率、囊胚形成率显著高于来自其它细胞数的单卵裂球(P<0.05),且其大部分内细胞团(ICM)细胞的碱性磷酸酶(AKP)表达呈阳性。结论:废弃胚胎来源的单卵裂球能在体外继续发育至囊胚,发育潜能与供体胚胎发育质量密切相关,其发育似乎延续原有供体卵裂球的节律,而形成囊胚所需时间明显缩短,细胞数亦明显减少,但囊胚ICM细胞显示AKP阳性,深信其利用价值会得到进一步证实。     

输卵管积液对小鼠胚胎体外发育的影响

目的 :了解输卵管积液是否具有胚治毒性。方法 :收集兔输卵管液和机械诱导的输卵管积液 ;小鼠超数排卵 ,收集 2 -细胞胚胎 ,随机分配到含有不同浓度输卵管积液、输卵管液 (正常对照 )和培养液 (空白对照 )中培养 ,观察并记录胚胎形态 ,同时测定新形成囊胚的细胞数和有丝分裂指数。结果 :1 0 0 %输卵管积液组囊胚形成率和胚胎孵化率均明显低于两对照组 (P<0 .0 0 1 ) ;而低浓度 (2 0 %和 1 0 % )积液组囊胚形成率和胚胎孵化率与两对照组相比 ,均无明显差异。各实验组囊胚的细胞数和有丝分裂指数均明显低于两对照组(P<0 .0 5)。结论 :机械诱导的输卵管积液 ,会影响早期种植前胚胎质量     

PGD周期中机械法和激光法活检对胚胎发育及妊娠结局的影响

目的:比较机械法和激光法进行卵裂球和极体活检对胚胎发育及着床前遗传学诊断(preimplantation genetic diagnosis,PGD)周期妊娠结局的影响。方法:本研究包括20对夫妇的21个PGD周期,其中18个周期分别用机械法或激光法于受精后第3天进行卵裂球活检,并用荧光原位杂交(fluorescence in situ hybridization,FISH)分析检出的卵裂球,于受精后第5或第6天移植信号正常的胚胎;2个周期分别用机械法和激光法在取卵后行极体活检,后行胞浆内单精子注射(introcytoplasmic sperm injection,ICSI)。同时将活检取出的极体进行FISH分析,于取卵后第3天移植经FISH检查正常的卵发育而来的胚胎。另外一个周期先用激光法实行了极体活检,由于FISH检查均无信号,后又用激光法对胚胎行卵裂球活检。结果:共活检胚胎145枚,其中109枚用机械法,36枚用激光法。活检后胚胎的继续发育率分别为72.48%和83.33%,囊胚形成率为33.94%和44.44%,临床妊娠率为38.46%和16.67%,着床率为21.43%和8.33%,两种方法无显著差异。对27枚卵行极体活检,其中12枚用机械法,15枚用激光法。活检后2PN受精率分别为58.33%和46.66%,继续发育率为66.67%和60.00%,亦无显著差异。对活检出的极体进行FISH分析,用机械法活检的极体信号阳性率为90.00%,显著高于激光法的28.57%。结论:用机械法和激光法行极体或卵裂球活检对胚胎发育的影响差异无统计学意义。但使用机械法活检卵裂球能获得较高的临床妊娠率和着床率。极体活检时能获得较高的受精率和继续发育率,故推荐使用机械法进行活检。     

影响冻融胚胎发育潜能及妊娠结局因素的探讨

目的:探讨胚胎冷冻复苏后,卵裂球存活状态对胚胎发育的影响以及体外授精(IVF)和卵胞质内单精子注射(ICSI)2种授精方式对冷冻胚胎复苏后体外发育能力和妊娠结局的影响。方法:回顾性分析142例患者,150个复苏周期,共769个冷冻胚胎复苏后培养至囊胚期进行移植的结果。结果:共复苏胚胎769个,存活胚胎702个,复苏率91.3%。220个胚胎(31%)到达囊胚阶段。在卵裂球全部存活胚胎中,囊胚形成率35%,部分存活胚胎中囊胚形成率24%,两者有统计学差异(P<0.01)。在卵裂球全部存活胚胎中,来源于IVF的胚胎囊胚形成率为40%,来源于ICSI的为26%,两者有统计学差异(P<0.01);部分卵裂球存活胚胎中来源于IVF的胚胎囊胚形成率为26%,来源于ICSI的为19%,差异无统计学意义(P>0.05)。在全部220个囊胚中,IVF组的优质囊胚率为38.6%,ICSI组的优质囊胚率为21.0%,差异有统计学意义(P<0.05)。临床妊娠率IVF组和ICSI组分别为61.05%与61.11%;胚胎种植率分别为37.50%与36.67%,活产率分别为81.03%与78.79%,差异均无统计学意义(P>0.05)。结论:胚胎冷冻复苏后卵裂球的损伤削弱了囊胚形成能力,影响卵裂期胚胎进一步发育,这与ICSI和冷冻胚胎复苏后发育潜能的降低有关,但其对临床结果和妊娠结局的影响不大。     

IVF-ET周期中1原核(PN)及0PN(2Pb)胚胎的染色体组成分析

目的:初步探寻体外受精-胚胎移植(IVF-ET)周期中高发育潜能的1原核(PN)及0PN(2Pb)胚胎的方法。方法:观察787个IVF周期患者的PN及卵裂情况,培养至第6日,观察其囊胚形成情况。取囊胚滋养层细胞活检,采用胚胎植入前遗传学筛查(PGS)技术检测0PN(2Pb)、1PN及2PN囊胚的染色体组成。结果:787个IVF周期共获卵8 352枚,2PN、0PN(2Pb)、1PN胚胎的形成率分别为64.35%、4.93%、3.65%,囊胚形成率分别为45.71%、30.03%、18.18%。PGS结果显示,1PN及0PN(2Pb)囊胚染色体正常的比例明显低于2PN囊胚,差异有统计学意义(P0.05)。0PN(2Pb)囊胚的染色体正常比例较1PN囊胚的略高,差异无统计学意义(P0.05)。此外,发育至第6日的0PN(2Pb)囊胚及1PN囊胚较第5日胚胎的正常染色体比例高。结论:对于本周期无可利用胚胎的患者,建议移植1PN及0PN(2Pb)来源的第6日评分较好的囊胚。     

玻璃化冷冻法冻融经植入前遗传学诊断后囊胚的应用初探

目的:探讨玻璃化冷冻技术冻融经卵裂球活检后囊胚的可行性。方法:将活检后剩余的可移植囊胚用玻璃化冷冻保存,并在冷冻前人工皱缩囊胚腔,在需要移植时予以解冻囊胚进行移植。结果:24例共进行24个活检周期,活检了159个胚胎,活检后胚胎囊胚形成率60.38%(96/159)。有17个周期共移植26枚新鲜可用囊胚,成功种植13个(50.0%),11例获得临床妊娠(64.71%),7个周期因无可移植胚胎或卵巢过度刺激等因素而取消移植。10例患者(10个周期)有30个可移植囊胚进行了玻璃化冷冻保存,其中6例患者因未成功生育要求解冻其囊胚进行移植。共解冻8枚囊胚,全部存活并移植,5例获单胎妊娠;2例已分娩正常婴儿,3例继续妊娠中。结论:玻璃化冷冻技术结合人工皱缩囊胚腔能冷冻保存经卵裂球活检后的囊胚。     

反复多周期促排卵对小鼠母体卵巢组织及胚胎发育潜能的影响

目的:比较多周期连续促排卵对小鼠卵巢组织和胚胎发育潜能的影响。方法:建立反复多周期促排卵小鼠模型(A组),观察其卵巢组织内各级卵泡数形态并计数。统计获取的卵母细胞及受精卵数、卵裂率、优质胚胎率和囊胚形成率,并与单次促排卵周期小鼠(B组)、自然周期排卵小鼠(C组)比较。结果:B组获取的卵母细胞数及受精卵数显著增多(41.6±11.0)。而A组获取的卵母细胞及受精卵数显著降低(5.5±2.9),但初级卵泡形态异常率(33.34%)和次级卵泡形态异常率(27.14%)显著高于C组(8.33%、5.62%)与B组(10.34%、8.97%)(P<0.01);卵裂率(44.83%)、优质胚胎率(0)和囊胚形成率(0)均显著低于C组(88.07%、75.09%、74.74%)和B组(81.05%、69.02%、66.94%)(P<0.01)。结论:单次促排卵能增加卵母细胞和胚胎的数量。但多次连续促排卵会增加卵巢内异常的初级卵泡和次级卵泡数,降低卵母细胞质量。同时,会降低优质胚胎率和囊胚形成率,影响卵裂后胚胎进一步发育的潜能。     

单胚胎移植的临床效果分析

目的探讨单胚胎移植的妊娠结局及可行性。方法对上海集爱遗传与不育诊疗中心1999-01-2006-06实施的所有体外受精-胚胎移植(IVF-ET)新鲜及冷冻周期中仅有单个胚胎可供移植的共455个周期进行回顾性总结,分析和比较单胚胎移植的妊娠结局与年龄、不孕时间、受精方式、胚胎卵裂球数、胚胎评分、内膜厚度、移植胚胎的天数及新鲜或冷冻胚胎移植的关系。结果单胚胎移植的临床妊娠率18.68%(85/455),无单卵双胎。妊娠与否(1)与年龄无明显相关关系(P>0.05)。(2)与不孕时间相关,妊娠者平均不孕时间为5.53年,未孕者6.73年,P<0.01。(3)与移植时胚胎的卵裂球数目与评分明显相关,妊娠者的平均卵裂球数及评分显著高于未孕组分别为(5.58±2.09)、(4.79±2.19)个;(2.31±0.69)、(2.56±0.73)分,P均<0.01。(4)与移植时胚胎的天数相关,第2(D2)、第3(D3)及第5(D5)天组的临床妊娠率分别为:15.58%,22.75%及26.47%。D3妊娠组所移植胚胎的平均卵裂球数及评分显著高于D2组、P<0.01;另外D5组胚胎达到囊胚的临床妊娠率为40%,而未达囊胚组仅20.83%。(5)IVF与ICSI的单胚胎移植结局无明显差异,临床妊娠率为IVF:20·25%(49/242)及ICSI:16·90%(36/213)。(6)新鲜胚胎(416例)与冷冻胚胎(39例)的单胚胎移植后的临床妊娠率分别为18.27%和23.08%,P>0.05;冷冻组的平均卵裂球数明显多于新鲜胚胎组(P<0.01)。结论IVF-ET周期选择第3天优质胚胎或囊胚行单胚胎移植,可以达到较高的妊娠率并减少多胎妊娠。     

Vitrification of mouse embryos at 2-cell, 4-cell and 8-cell stages by cryotop method

Purpose

The objective of this study was to investigate the effects of vitrification on the preimplantation developmental competence of mouse 2-cell, 4-cell and 8-cell stage embryos.

Methods

Mouse 2-cell, 4-cell and 8-cell stage embryos were cryopreserved using the cryotop vitrification method and subsequently warmed on a later date. The embryos were then assessed by their morphology, blastocyst formation and hatching rates. Additionally, trophectoderm (TE) and inner cell mass (ICM) cell numbers were compared in hatched blastocysts from the control and experimental groups.

Results

Vitrified embryos at the 2-cell, 4-cell and 8-cell stages appeared morphologically normal after warming. The overall survival rate of vitrified embryos at various stages after warming was 96.7% and there were no significant differences among 2-cell stage (96.0%), 4-cell stage (96.8%) and 8-cell stage (97.1%) embryos (P?>?0.05). The blastocyst formation rate (69.4%) and hatching rate (52.6%) of vitrified 2-cell embryos were significantly lower than that from the control group and vitrified 8-cell embryos (P?<?0.05). In the vitrified 4-cell embryo group, the blastocyst formation rate (90.3%) was similar to the 8-cell group (91.2%), but the hatching rate (60.0%) was significantly lower than that of the non-vitrified control ( 84.1%) and vitrified 8-cell embryo (78.4%) groups (P?<?0.05). When further development to the fully hatched blastocyst stage was compared, hatched blastocysts derived from vitrified 2-cell, 4-cell and 8-cell embryos had significantly lower cell counts both in the ICM and TE, as compared to fresh blastocysts (P?<?0.05). Among the vitrified 2-cell, 4-cell and 8-cell embryo groups, there were no significant differences in the cell counts of ICM and TE (P?>?0.05).

Conclusions

Although cryotop vitrification was suitable for the cryopreservation of mouse embryos from the 2-cell stage, 4-cell stage and 8-cell stage without significant loss of survival, vitrification had an adverse effect on the development of 2-cell embryos. Mouse embryos at the 8-cell stage had the best tolerance for vitrification and would yield the highest level of post-vitrification developmental competence among early cleavage stage embryos. Nevertheless, it is unclear how these findings can be extrapolated to human embryos.     

Human embryo biopsy on the 2nd day after insemination for preimplantation diagnosis: removal of a quarter of embryo retards cleavage.

OBJECTIVE: To assess any reduction in viability and development in vitro after biopsy of a quarter of the cells of human embryos on day 2 after insemination. DESIGN: A prospective study in which normally fertilized surplus embryos of good morphology with two to eight cells approximately 48 hours after insemination were randomly allocated to a control or biopsied group, respectively. SETTING: In vitro fertilization (IVF) unit and laboratories of the Hammersmith Hospital, Institute of Obstetrics and Gynaecology, London University. PATIENTS, PARTICIPANTS: One hundred twenty-nine embryos from 28 infertile IVF patients. INTERVENTIONS: Follicular aspiration by ultrasound-guided transvaginal puncture and embryo biopsy by micromanipulative procedures. MAIN OUTCOME MEASURE(S): Pyruvate uptake and cell number at the blastocyst stage. RESULTS: Embryo biopsy did not have an adverse effect on either the proportion developing to the blastocyst stage (50% [32 of 64] and 47.7% [31 of 65] for the control and biopsied groups, respectively) or embryo viability, measured indirectly through pyruvate uptake. However, the proportion of embryos that reached the morula stage after day 4 (retarded embryos) was significantly higher (44%, 11 of 25 versus 8.7%, 2 of 23) in the biopsied group. The total number of cells (29.6 +/- 3.1 versus 62.4 +/- 4.7), numbers of inner cell mass (7.7 +/- 2.2 versus 24.5 +/- 1.4) and trophectoderm (24.0 +/- 5.2 versus 45.0 +/- 6.4) cells, and the inner cell mass:trophectoderm ratio (34.7 +/- 7.9 versus 59.5 +/- 11.7) were strikingly reduced at the blastocyst stage in the biopsied group. This reduction was greater in embryos that reached the morula stage after day 4. CONCLUSIONS: More investigation is needed to assess whether the detrimental effects observed were because of the biopsy method used in this study or to a high sensitivity of human embryos at early stages to manipulation in vitro.     

表皮生长因子(EGF)和胰岛素样生长因子(IGF-Ⅱ)对小鼠1-细胞胚胎体外发育的影响

目的:研究表皮生长因子(epidermalgrowthfactor,EGF)在小鼠早期胚胎体外发育中的作用,以及EGF联合胰岛素样生长因子-Ⅱ(insulin-likegrowthfactor-II,IGF-Ⅱ)对小鼠早期胚胎体外发育是否有协同促进作用。方法:①在mKSOM培养液中添加0ng/ml(对照组)、0.1ng/ml、1ng/ml、10ng/ml、100ng/ml的EGF、10ng/mlIGF-Ⅱ、1ng/mlEGF+1ng/mlIGF-Ⅱ、1ng/mlEGF+10ng/mlIGF-Ⅱ、10ng/mlEGF+1ng/mlIGF-Ⅱ、10ng/mlEGF+10ng/mlIGF-Ⅱ培养小鼠1-细胞胚胎,每组胚胎在培养箱中连续培养120h,每24h观察胚胎发育情况,分别计算2-细胞率、4-细胞率、桑椹胚率、囊胚率和孵化率,并进行囊胚细胞计数。结果:添加1ng/ml、10ng/mlEGF组的囊胚率及孵化率显著增加;EGF+IGF-Ⅱ组较单一添加组、对照组囊胚率及孵化率显著增加(P<0.05),且EGF+IGF-Ⅱ组囊胚细胞计数显著高于其他组(P<0.05),其中10ng/mlEGF+10ng/mlIGF-Ⅱ组的孵化率及囊胚细胞数最高(P<0.05)。结论:EGF浓度在1￣10ng/ml范围内可以提高体外培养鼠胚的囊胚率及孵化率;EGF及IGF-Ⅱ对体外培养鼠胚的发育有协同促进作用;本实验范围内10ng/mlEGF+10ng/mlIGF-Ⅱ为最优组合。     

Effect of fragment removal on blastocyst formation and quality of human embryos

Blastomere fragmentation is one of the most significant defects in cleaving embryos. Scientists believed that removing the fragments was a possible way to reduce their unwanted effects. This hypothesis has been tested in some studies in which the development of human fragmented embryos was followed in vivo after all fragments were removed, but little is known about the potential for in-vitro development of such embryos, which is the subject of the present study. For this purpose, 4-6 cell surplus human embryos were scored according to the degree and pattern of fragmentation into four grades, allocated into two groups of control and fragmentation removal (experimental) and cultured sequentially. At the end of day 6 of culture, in the experimental group especially in grade IV blastocyst rate, size and number of blastomeres in each blastocyst were all improved compared with those of the control group (42.3 versus 20.0%; 19,205.7 +/- 1060.3 versus 15,825.9 +/- 448.7 microm(2) and 100.14 +/- 13.48 versus 63.75 +/- 19.79 respectively, P < 0.05). In the grade IV embryos, apoptotic index was also significantly reduced after embryo fragmentation removal (3.40 +/- 0.88 versus 22.99 +/- 4.45, P < 0.05). In conclusion, fragmentation removal had a positive effect on human fragmented embryos and produced the best quality blastocysts.     

肿瘤转移抑制因子CD82/KAI1对植入前小鼠胚胎体外发育的影响

目的:研究CD82/KAI1mRNA及蛋白质在小鼠胚胎中的表达规律及其对小鼠胚胎体外发育的影响。方法:①应用RT-PCR及免疫荧光技术观察CD82/KAI1mRNA及蛋白质在小鼠不同发育时期胚胎中的表达规律。②在不同CD82/KAI1抗体浓度的培养液中,培养小鼠8-细胞胚胎,观察囊胚发育率、孵化率和胚胎细胞数的变化。结果:①CD82/KAI1mRNA在小鼠不同时期胚胎中均有表达,于8-细胞期及桑葚胚表达较丰富,CD82/KAI1蛋白表达于各期胚胎细胞的胞膜和胞浆,在桑葚胚期CD82蛋白还强表达于胚胎细胞的胞核。②一定浓度的CD82/KAI1抗体可明显抑制胚胎的发育速度(1∶800,P<0.05),降低囊胚的形成率(1∶400,P<0.05)和孵出率(1∶800,P<0.05),减少囊胚细胞数(1∶800,P<0.05)。结论:CD82/KAI1在小鼠胚胎的发育过程中可能发挥重要作用。     

人卵泡液对小鼠胚胎生长发育影响的研究

目的：探讨人卵泡液对小鼠胚胎生长发育的影响。方法：在培养液中分别加入人卵泡液（卵泡液组）和人血清（血清组）,观察和检测2细胞期鼠胚在体外发育至8细胞期、囊胚期以及鼠胚孵出的比率;用放射免疫方法测定人卵泡液和血清中表皮生长因子（EGF）含量。结果：卵泡液组有72.9%的2细胞期鼠胚能发育到8细胞期,血清组仅有48.0%到达8细胞期;继续培养显示,卵泡液组细胞分裂较快,有50.9%的鼠胚可发育至囊胚期,并有26.3%孵出,明显高于血清组（24.5%,6.9%),两组比较,差异有显著性（P＜0.05)。卵泡液中EGF的含量为0.50μg/L,血清中为0.26μg/L,两组比较,差异有显著性（P＜0.05）。结论：卵泡液对早期胚胎发育有促进作用,在早期胚胎培养中,添加人卵泡液比添加人血清对提高早期胚胎培养质量更为有效。     

Comparison of effects of zona drilling by non-contact infrared laser or acid Tyrode's on the development of human biopsied embryos as revealed by blastomere viability, cytoskeletal analysis and molecular cytogenetics

Use of a non-contact infrared laser (IRL) or acid Tyrode's for zona drilling before embryo biopsy was compared by assessing blastomere viability using various fluorescent markers or culture of the single biopsied blastomere, and, by cytoskeletal and molecular cytogenetic analysis of the biopsied embryos following culture to the blastocyst stage. There was no significant difference in the proportion of biopsied embryos that showed no damage in both the biopsied blastomere and in the remaining embryo (acid Tyrode's: 75% versus IRL: 68%), or in the proportion of single biopsied blastomeres that divided in culture (P > 0.05). However, single biopsied blastomeres from laser drilled embryos showed a greater tendency to form miniblastocysts. The proportion of laser or acid Tyrode's biopsied embryos that reached the blastocyst stage by day 6 was similar, although evident earlier (day 5) in the laser biopsied embryos. Spindle abnormalities at the blastocyst stage included tripolar and tetrapolar spindles, but their incidence was not significantly different from controls. In addition, no significant difference was observed in the incidence of chromosomal abnormalities and mosaicism between the two groups. It is concluded that using an IRL at a safe working distance does not cause adverse immediate or longer term effects on the development of human biopsied embryos, although damage can occur if drilling within this distance is unavoidable. Acid Tyrode's drilling can also cause damage, and tended to retard blastocyst development.     

Aspects of biopsy procedures prior to preimplantation genetic diagnosis

Today, preimplantation genetic diagnosis (PGD) is offered in over 40 centres worldwide for an expanded range of genetic defects causing disease. This very early form of prenatal diagnosis involves the detection of affected embryos by fluorescent in situ hybridization (FISH) (sex determination or chromosomal defects) or by polymerase chain reaction (PCR) (monogenic diseases) prior to implantation. Genetic analysis of the embryos involves the removal of some cellular mass from the embryos (one or two blastomeres at cleavage-stage or some extra-embryonic trophectoderm cells at the blastocyst stage) by means of an embryo biopsy procedure. Genetic analysis can also be performed preconceptionally by removal of the first polar body. However, additional information is then often gained by removal of the second polar body and/or a blastomere from the embryo. Removal of polar bodies or cellular material from embryos requires an opening in the zona pellucida, which can be created in a mechanical way (partial zona dissection) or chemical way (acidic Tyrode's solution). However, the more recent introduction of laser technology has facilitated this step enormously. Different biopsy procedures at different preimplantation stages are reviewed here, including their pros and cons and their clinical applications. The following aspects will also be discussed: safety of zona drilling by laser, use of Ca2+/Mg2+-free medium for decompaction, and removal of one or two cells from cleavage-stage embryos.     

Effect of glutamine on preimplantation mouse embryo development in vitro

OBJECTIVES: The purpose of this research was to study the independent effect of the amino acid glutamine on preimplantation mouse embryo development in vitro. STUDY DESIGN: Two-cell stage mouse embryos were cultured in human tubal fluid medium in the presence and absence of 1 mmol/L of glutamine. Outcomes for morphology and cleavage rates were compared with Fisher's and Mann-Whitney's tests, respectively. RESULTS: Glutamine increased the proportion of embryos that developed to the blastocyst stage (86.4%) compared with those cultured without glutamine (59.1%) (P =.052). The percentages of embryos developing to the morula or hatching blastocyst stages were comparable in the 2 groups. Blastocyst total cell numbers were significantly higher in the glutamine group (34+/-1.7 vs 18.5+/-3.5, respectively; values are mean+/-SEM, P =.044). CONCLUSION: The amino acid glutamine independently improves preimplantation mouse embryo development in vitro. Further studies are needed to examine the applicability of these results to humans.