小鼠胚胎分割方法及同卵双生试验

选择小鼠晚期桑椹胚和早期囊胚,采用下列方法进行分割:A、显微手术刀直接分割;B、酶消化透明带后分割;C、显微玻璃针去带分割;D 酶——机械去带分割。共分割277枚胚胎,分割成功264枚(95.3%)。将其中480枚半胚作体外培养,A,B,C,D 各组半胚发育到囊胚的发育率分别为65.7%(92/140)、54.2%(65/120)、63(63/100)、64.2%(77/120)。将用 A法分割的48枚半胚移植于12只受体鼠,结果有4只怀孕,共产11只半胚鼠,其中4对有同卵双生仔鼠。     

胚胎分割液及分割方法对绵羊体外胚分割效果的影响

主要研究了胚胎分割液、分割方法和胚胎发育时期对绵羊体外生产胚胎的影响.体外采集绵羊卵丘卵母细胞复合体,成熟培养24 h,经过体外受精培养,得到体外胚胎样品.借助显微操作仪,将体外受精的桑葚胚和囊胚分割,体外培养半胚,观察其发育情况.结果发现:在D-PBS+0.2 mol/L蔗糖液与D-PBS+5%PVP液中分割桑葚胚和囊胚,其分割成功率及半胚的囊胚发育率及囊胚细胞数三者均无差异显著性(P＞0.05);用显微分割法和徒手分割法分割桑葚胚和囊胚,其分割成功率、半胚的囊胚发育率及囊胚细胞数均无差异显著性(P＞0.05);比较桑葚胚和囊胚分割,囊胚的分割成功率显著高于桑葚胚的分割成功率(P＜0.05),而半胚的囊胚发育率及半胚细胞数均无差异显著性(P＞0.05).结果表明:在D-PBS液中分别添加0.2 mol/L的蔗糖和5%的PVP都可作为绵羊体外胚的胚胎分割液;显微分割法和徒手分割法均可用于绵羊体外胚胎的分割;囊胚比桑葚胚更适于胚胎分割.     

绵羊半胚移植的研究

本试验用含5％灭活羊血清的PBS为冲卵液,冲出绵羊胚胎,选择质量好的晚期桑椹胚和囊胚,保存在含20％灭活羊血清的PBS中,然后在立体显微镜下,用胚胎简易分割法平均分割胚胎。共分割34枚绵羊胚胎,分割成功率为85.3％(58/68),其中A级胚胎的分割成功率为95.7％(44/46),B级胚胎的分割成功率为63.6％(14/22)。将29枚裸半胚,移植于10只受体绵羊子宫,结果6只妊娠,共产12只羊羔,其中两对为同卵双生羊羔,妊娠率达60％(6/10),半胚成活率达41.4％(12/29)。在10只受体中,各移4枚半胚的4只受体绵羊均妊娠,其中一只产3只羊羔。     

小鼠冻胚分割试验

研究了分割所用溶液、冷冻前胚胎发育时期和分割后将半胚是否装入透明带对冻胚分割效果的影响。结果证明:①将解冻囊胚分割后,无论是否将半胚装入透明带对冻胚分割的效果均无显著影响(P>0.05);②在PBS中分割解冻桑椹胚和囊胚的效果无显著差异(P>0.05);③与分割解冻桑椹胚相比,在蔗糖液中分割解冻囊胚可显著提高冻胚分割效果(P<0.05)。将在蔗糖液中分割冻囊胚获得10对半胚移植于5只受体,结果有2只妊娠,共获得半胚仔鼠6只,其中2对为同卵双生。     

程序化冷冻对小鼠胚胎发育的影响

取小鼠原核(220枚)、2～4细胞胚胎(227枚)、桑椹胚(127枚),将其分为3组,每一时期胚胎分成两半,一半取出后立即冷冻复苏并体外培养至囊胚,另一半体外培养至囊胚后冷冻复苏,子宫冲取囊胚(78枚)冷冻复苏为对照组;各组囊胚均移植至于宫,比较程序化冷冻对小鼠早期胚胎存活率的影响.结果表明:原核、2～4细胞胚胎、桑椹胚体外培养至囊胚后冷冻复苏率分别为56.4%、72.2%、81.6%,移植产仔率分别为38.1%、41.6%、56.8%,原核、2～4细胞组复苏率和产仔率极显著或显著低于对照组,桑椹胚组与对照组差异不显著,显示体外培养对早期胚胎冷冻存活有影响;原核、2～4细胞胚胎、桑椹胚冷冻后体外培养至囊胚,胚胎移植后产仔率分别为25.3%、28.2%、42.1%,与对应胚胎时期体外培养至囊胚冷冻复苏后移植产仔率相比,原核、2～4细胞组均存在显著差异,而桑椹胚组差异不显著,显示原核、2～4细胞的早期胚胎体外培养至囊胚后冷冻可提高冷冻存活率.     

小鼠二分胚发育的观察

本试验用含5％灭活羊血清的PBS为冲卵液,冲出小鼠胚胎,选择质量好的晚期桑椹胚和早期囊胚,保存在含20％天活羊血清的PBS中,然后在立体显微镜下分割胚胎。共分割174枚小鼠胚胎,分割成功率为87.4(258/294),将218枚小胚二分胚体外培养20小时,发育到优秀囊胚率为65.5％(143/218),出现假囊胚率为18,3％(40/218),出现滋养外胚层囊及非整合型的胚胎率为16,1％(35/218)。     

小鼠冻胚分割试验

研究了分害虫所用溶液，冷冻前胚胎发育时期和分割后将半胚是否装入透明带对冻胚分割效果的影响，结果表明：①将解冻囊胚分割后，无论是否将半胚装入透明带对冻胚分割的效果均无显著影响（P＞0.05）；②在PBS中分割解冻桑椹胚和囊胚的效果无显著差异（P＞0.05）；③与分割解冻桑椹胚相比，在蔗糖液中分割解闲囊胚可显著提高冻胚分割效果（P＜0.05）。将在蔗糖液中分割冻囊胚获得10对半胚移植于5只受体，结果有2只妊娠，共获得半胚仔鼠6只，其中2对为同卵双生。     

卵母细胞经体外成熟、受精及用输卵管细胞共培养后产羔

卵母细胞经体外成熟、受精处理后,转移到中间受体母羊体内培养。5天后,回收到59％的卵子,其中31枚(38％)达到桑椹或囊胚期胚胎,移植给6只受体母羊,结果5只妊娠,其中4只保持妊娠,并产羔羊9只(43％)。本试验,72个卵母细胞成熟和体外受精,用羊输卵管细胞共培养5天,31个受精卵(43％)发育到非植入桑椹胚,21个胚胎移植到11只受体体内,结果2只(18％)妊娠,并产2只公羔。结果表明:体外成熟和受精的羊卵与绵羊输卵管上皮细胞共培养以通过预移植阶段,这对其进一步发育到移植时期是适合的。     

不同发育时期鼠胚对一步细管内冷冻一解冻耐受性的研究

本试验采用一步添加防冻剂（１０％甘油）、１２．５％蔗糖一步细管内脱除甘油，３７℃温水快速解冻法，对３９３枚处于不同发育时期的优良胚胎做了冷冻研究，旨在探索不同发育时期的胚胎对一步细管内冷冻解冻耐受性存在的差异，为哺乳动物胚胎冷冻和移植提供资料。解冻后体外培养结果表明，晚期桑椹胚（包括致密桑椹胚和致密后桑椹胚两个阶段）的抗冻能力最强，体外发育率致密桑椹胚为８０．０％（３２／４０）、致密后桑椹胚为７８．０％（３２／４１）；早期桑椹胚和早期囊胚次之，体外发育率为６２．２％（２８／４５）和６６．１％（３９／５９）；囊胚和扩展囊胚的抗冻能力最低，体外发育率仅为５１．６％（３１／６０）和５４．５％（１８／３３）。     

不同培养体系对绵羊体外受精胚胎发育及细胞凋亡的影响

[目的]通过SOFaaBSA和CR1 aaBSA - FBS两种培养液对体外胚胎发育率及胚胎凋亡发生的影响,筛选适合绵羊体外受精胚胎发育的培养体系,为相关研究提供一定的理论依据和研究基础.[方法]采用激光共聚焦显微镜和细胞原位凋亡检测技术(TUNEL),分析这两种胚胎体外培养系统的绵羊体外受精胚胎发育的影响及各发育阶段的细胞凋亡状况及对胚胎发育的影响.[结果]SOFaaBSA和CR1aaBSA- FBS组的卵裂率、囊胚率和囊胚孵化率均高与其它实验组,但这两组之间差异不显著(P＞0.05).同时,在两种培养液培养的2细胞、3-8细胞期的绵羊体外受精正常形态的胚胎中均未发现凋亡信号,凋亡信号在两种培养液中都是首次出现在9- 16细胞胚胎细胞中,并且随着胚胎发育至囊胚期,凋亡细胞效随着胚龄增长越来越多.在SOFaaBSA培养液培养的桑椹胚和囊胚细胞胚胎凋亡率显著低于CR1aaBSA - FBS培养液培养的桑椹胚和囊胚(P＜0.05),同时,在CR1aaBSA- FBS培养液中桑椹胚和囊胚细胞平均具有凋亡细胞的数量显著高于SOFaaBSA培养液(P＜0.05).[结论]CR1aaBSA- FBS培养系统显著的增加了绵羊晚期体外胚胎的凋亡.CR1 aaBSA - FBS能够支持绵羊体外受精胚胎的发育,但SOFaaBSA培养液更适合绵羊体外胚胎的发育.     

In Vitro Developmental Potential of Cloned Embryos Derived from Bovine Somatic Cells and Rabbits Oocyte

180 reconstituted embryos were produced by nuclear transplantation using bovine ear fibroblasts at G0 or non-G0 stage as donor nuclei and oocytes collected from superovulated multiparous or young rabbits as recipients. After cultivation in two kinds of medium M199+ 10%FBS or RD+ 10%FBS, 112 of them developed to 2-cell stage (62.2%) and 26 to morula stage (14.4%) and 20 of them eventually developed to blastocyst stage (11. 1% ). There is no significant difference for the cleavage rates in two groups of reconstituted embryos derived from G0-stage and non-G0 stage donor cells respectively. However, G0-stage donor cells could result in higher rate of 8-cell - 16-cell stage embryos significantly (P＜0.05), as well as higher rate of blastocysts (P＜0.01). It seems that using two different culture systems had no significant effects on the cleavage rate, morula rate or blastocyst rate (P＞0.05).     

巨噬细胞集落刺激因子(GM-CSF)对小鼠胚胎体外发育的影响

以小鼠自然受精与体外受精胚胎为模型,探索鼠源巨噬细胞集落刺激因子(GM-CSF)在小鼠胚胎早期发育过程中的生理功能。分别使用添加不同剂量(对照组:0 ng.mL-1;试验组:0.5、2和10 ng.mL-1)GM-CSF的化学限定培养基连续培养小鼠自然受精、体外受精原核期与2细胞期胚胎,检测其胚胎着床前发育效率(卵裂率、囊胚率)及囊胚的质量(囊胚总细胞数、ICM/总细胞数的比率、凋亡指数)。结果发现,对自然受精胚胎而言,原核时期添加不同剂量的GM-CSF,其卵裂率、囊胚总细胞数、ICM/总细胞数的比率在各组之间均差异不显著,但10 ng.mL-1试验组的囊胚率显著低于对照组(61.6±5.1)%(P0.05);2细胞时期添加不同剂量的GM-CSF,其囊胚率、囊胚总细胞数、ICM/总细胞数的比率在各组之间均差异不显著,但试验组中的囊胚凋亡指数均显著低于对照组(P0.05)),并且试验组中2 ng.mL-1的囊胚凋亡指数最低,显著低于0.5 ng.mL-1(P0.05),其他试验组之间的囊胚凋亡指数没有统计学上的差异性。对体外受精胚胎来说,原核时期添加GM-CSF,其卵裂率、囊胚率、囊胚总细胞数、ICM/总细胞数的比率在各组之间均无显著性差异;在2细胞时期,10 ng.mL-1组的囊胚率显著低于对照组及其他2个试验组(P0.05),但各组之间的囊胚总细胞数、ICM/总细胞数的比率均无显著性差异。本研究结果表明,在化学限定培养基中添加一定剂量的GM-CSF有利于改善小鼠自然受精与体外受精囊胚的质量,但剂量过高可能不利于小鼠受精胚胎的早期发育。     

Production of early monozygotic twin bovine embryos in vitro by the blastomere separation and coculture technique

The objective of this study was to establish an efficient system of producing early monozygotic twin bovine embryos in vitro using the blastomere separation and coculture technique. In this study, early eight-cell embryos were chosen to optimize the separation method, and multi-coculture tactics were applied to improve the efficiency of this production system. Bovine embryo blastomeres(groups of at least 30 at the eight-cell stage) were separated into eight segments(to regard an eight-cell embryo as a tangerine, a blastomere as one segment) and one, two and four segments(blastomeres) were cultured respectively in microwells on the bottom of the four-well dish(Nunc, Denmark) with 400 μL of culture medium under paraffin oil. Four different types of coculture tactics(cocultured with nothing, intact embryos, bovine cumulus cells(b CCs), intact embryos b CCs) were applied to the group of four segments(blastomeres). Finally, diameter and inner cell mass(ICM):trophectoderm(TE) cell ratio was measured as a criterion to assess the quality of the twin embryos which were derived from bovine separated blastomeres. Our results showed that rate of blastocyst formation of the four segments group was significantly greater than one or two group(P0.05). In addition, rate of blastocyst formation was significantly increased when the four segments were cocultured with intact embryo b CCs(P0.05). Although the ICM, TE and total cells of blastocysts derived from separated blastomeres was less than the control group from intact embryo(P0.05), more important quality indicator of the blastocyst diameter and ICM:TE cell ratio was similar between our experimental group and the control group(P0.05). Thus, these results suggest that combined with intact embryos b CCs coculture system, culturing four isolated segments(blastomeres) per microwell is an efficient system of producing early monozygotic twin bovine embryos. Furthermore, our results also indicate that the quality of blastocysts derived from separated blastomere may be similar to those derived from intact eight-cell embryos.     

猪胚胎体外培养体系优化对胚胎干细胞建系的影响

为提高体外胚胎发育质量和体外胚胎建立胚胎干细胞系效率,研究以N2B27为基础的干细胞培养体系对猪孤雌胚胎体外发育和后续建立胚胎干细胞系的影响。设立3个试验组:PZM-3组,孤雌激活的胚胎全程PZM-3培养体系中培养; N2B27组,孤雌激活的胚胎全程N2B27培养体系中培养; PZM-3-N2B27组,孤雌胚胎在PZM-3培养体系中培养至桑葚胚后更换为N2B27培养体系。结果表明,N2B27组无法获得囊胚,但PZM-3-N2B27组胚胎可正常发育至囊胚,囊胚率未显著提高,但囊胚细胞总数显著提高(P<0.05)。PZM-3-N2B27组获得孤雌囊胚用于建立猪胚胎干细胞系,显著提高原代克隆形成率(P<0.05),获得猪胚胎干细胞系呈碱性磷酸酶阳性,表达Oct4、Sox2和Nanog等多能性基因。结果表明,采用PZM-3和N2B27培养体系结合获得的猪孤雌囊胚利于猪胚胎干细胞系建立。研究为进一步优化猪胚胎体外培养体系,获得初始态胚胎干细胞系提供参考。     

In vivo and in vitro development of Tibetan antelope (Pantholops hodgsonii) interspecific cloned embryos

The Tibetan antelope is endemic to the Tibetan Plateau, China, and is now considered an endangered species. As a possible rescue strategy, the development of embryos constructed by interspecies somatic cell nuclear transfer (iSCNT) was examined. Tibetan antelope fibroblast cells were transferred into enucleated bovine, ovine and caprine oocytes. These cloned embryos were then cultured in vitro or in the oviducts of intermediate animals. Less than 0.5% of the reconstructed antelope-bovine embryos cultured in vitro developed to the blastocyst stage. However, when the cloned antelope-bovine embryos were transferred to caprine oviducts, about 1.6% of the embryos developed to the blastocyst stage. In contrast, only 0.7% of the antelope-ovine embryos developed to the morula stage and none developed to blastocysts in ovine oviducts. The treatment of donor cells and bovine oocytes with trichostatin A did not improve the embryo development even when cultured in the oviducts of ovine and caprine. When the antelope-bovine embryos, constructed from oocytes treated with roscovitine or trichostatin A, were cultured in rabbit oviducts 2.3% and 14.3% developed to blastocysts, respectively. It is concluded that although some success was achieved with the protocols used, interspecies cloning of Tibetan antelope presents difficulties still to be overcome. The mechanisms resulting in the low embryo development need investigation and progress might require a deeper understanding of cellular reprogramming.     

Factors Affecting the Efficiency of Embryonic Cell Nuclear Transfer in Rabbits

Factors affecting the efficiency of nuclear transfer （NT） in rabbits were examined in the present study. When 100 V mm of pulse strength and 15 us of pulse duration were employed, 3 and 4 electronic pulses resulted in significantly more cytoplasts fused with donor cells compared with 2 electronic pulses （P〈 0.05）, but no significant difference was found in the cleavage rate of reconstructed embryos among the three groups （P〉0.05）. When the duration and number of electronic pulse were fixed at 15 ps and 3 times, increase of pulse intensity from 100 V mm 1 to 150 V mm^-1 and 200 V mm^-1 resulted in a significantly decrease in the cleavage rate of reconstructed embryos （P〈 0.05）, although the fusion rate did not significantly differ among the three groups （P〉 0.05）. Significantly more reconstructed embryos cleaved and developed to blastocysts when they were derived from donor embryos at the 8-16-cell stage, in comparison with the reconstructed embryos derived from donor embryos at the compact morula stage （P 〈 0.05）, although the fusion rate was similar （P 〉 0.05）. Activation of cytoplasts prior to fusion increased the cleavage rate （P〈 0.05） and blastocyst development （P〈 0.05） of reconstructed embryos, but decreased the fusion rate （P 〈 0.05） compared with cytoplasts activated post fusion. More reconstructed embryos developed to blastocysts when they were cultured in TCM ＋ 3% OCS at the first 48 h and then cultured in TCM199＋ 10% FCS, in comparison with the reconstructed embryos cultured in either TCM199＋ 10% FCS or TCM199＋3% OCS （P 〈 0.05）. When 22 NT embryos were transferred into the oviducts of one recipient rabbit, one recipient rabbit delivered a female rabbit at 34 days of gestation. In conclusion, either electrofusion parameter or developmental stage of donor embryos have a significant effect on the efficiency of NT, NT embryos require different concentration of serum at their different development stages.     

小鼠超数排卵与早期胚胎体外培养效果研究

为探讨冲胚方法对小鼠超数排卵效果的影响,分别采用子宫切碎法与子宫冲胚法对超排小鼠进行了冲胚。结果表明:子宫冲胚法的平均采卵数和平均获胚数极显著高于子宫切碎法(P0.01),而平均可用胚数显著高于子宫切碎法(P0.05),两种方法的平均未受精卵数则差异不显著(P0.05),说明冲胚方法对小鼠超数排卵效果的影响显著,且子宫冲胚法明显优于子宫切碎法。小鼠早期胚胎发育观察结果表明:超排处理后,在公母鼠合笼后76~79.5 h采胚,胚胎大多处于桑椹胚期,而在公母鼠合笼后88~91.5 h采胚,胚胎大多处于致密桑椹胚期与囊胚期;采用TCM199+15%胎牛血清培养液对小鼠胚胎进行体外培养是可行的。