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1.
研究旨在探讨秋水仙碱化学去核在山羊卵母细胞去核中的应用及其对卵丘细胞核移植胚胎体外发育的影响。结果表明:用秋水仙碱处理山羊体外成熟19h的卵母细胞,可使其核区形成胞质突起,以此为指示进行显微操作去核率可达100%,且用0.8μg/mL秋水仙碱处理30min的山羊卵母细胞突起率可达91.27%,显著高于对照组及0.4μg/mL处理组(P<0.05),与1.6μg/mL处理组的突起率差异不显著(P>0.05)。通过比较盲吸去核法与秋水仙碱化学去核法构建的山羊卵丘细胞核移植胚胎的体外发育能力发现,秋水仙碱化学去核法构建的重构胚体外发育能力较高,桑椹胚发育率显著高于盲吸去核法(P<0.05)。  相似文献   

2.
本研究在筛选猪化学辅助手工去核最佳脱羰秋水酰碱(Demecolcine,DC)浓度的基础上,探讨了各种因素对手工重构胚发育的影响,以期建立高效的猪手工体细胞核移植技术体系.观察不同成熟时间卵母细胞在不同DC浓度下的去核效率,并进一步比较了化学辅助手工去核法和荧光染色去核法、不同类型的供体细胞(颗粒细胞、新生巴马肌肉成纤维细胞和胎儿成纤维细胞)和供体细胞的不同处理方法(70%~80%汇合、血清饥饿法和100%接触抑制法)对重构胚发育能力的影响.结果表明:(1)利用DC诱导去核,对体外成熟培养44 h的卵母细胞以浓度0.4 μg· mL-1作用0.5~1 h为宜.(2)用DC化学辅助手工去核与用荧光染色去核的重构胚囊胚发育率差异不显著(13.11% vs 9.25%,P>0.05).(3)以胎儿成纤维细胞、颗粒细胞和新生巴马小型猪肌肉成纤维细胞为供体构建的重构胚的融合率、卵裂率及囊胚率均差异不显著(P>0.05).(4)用70%~80%汇合(对照组)组、接触抑制组和血清饥饿组的细胞作供体构建的重构胚,在融合率上,接触抑制组显著高于对照组(P<0.05);在分裂率与囊胚率上,各组之间均无显著差异(P>0.05).研究结果表明,化学辅助手工去核法在实际生产中可以替代荧光染色去核法,能省去去核过程中荧光染色及紫外光照射去核等步骤,从而简化了猪手工体细胞核移植程序,提高了猪手工体细胞核移植效率,能为高效的猪手工体细胞核移植技术体系的建立提供参考.  相似文献   

3.
何志全  窦忠英 《中国兽医科技》2006,36(12):1013-1018
为探讨不同激活剂的卵母细胞孤雌激活效果及激活胚体外发育情况,用乙醇、CaA23187、SrCl2、6-DMAP及CB分别对小鼠卵母细胞进行了激活处理.结果显示,70 mL/L乙醇刺激小鼠卵母细胞时,以激活5~7 min的激活效果及孤雌胚发育较好,桑囊胚发育率可达29.11%;用SrCl2激活小鼠卵母细胞时,6~10 mmol/L为最佳处理浓度,3~6 h为最佳激活时间,桑囊胚发育率可达16.67%;以70 mL/L乙醇激活5 min,再用2 mmol/L 6-DMAP+5 μg/mL CB激活3 h效果最佳,桑囊胚发育率高达35.77%.研究证实,小鼠卵母细胞经乙醇、6-DMAP和CB等复合激活后能较好地发育.  相似文献   

4.
采用成年小鼠的卵丘细胞核、胎儿成纤维细胞作核供体细胞来进行核移植,研究小鼠卵母细胞的去核程序和影响重构胚附植前发育的激活条件;随后将重构胚与供体细胞系共培养后获得囊胚阶段的小鼠重构胚,并将其移植到受体鼠体内后获得了24%克隆胚胎。结果表明,小鼠卵母细胞质能够进行重编程来支持早期的胚胎发育。  相似文献   

5.
本实验以昆明小鼠为研究对象,探讨了5 mmoL/L、10 mmoL/L及20 mmoL/L氯化锶(SrCl2)激活去透明带MⅡ期卵母细胞的效果,并比较了孤雌激活卵母细胞在普通DMEM培养液与添加有10 ng/mL有白血病抑制因子(LIF)的DMEM培养液中的体外发育率,旨在探讨去透明带卵母细胞适宜的SrCl2孤雌激活浓度及孤雌胚胎体外培养体系。结果表明:10 mmoL/L与5 mmoL/L SrCl2作用6 h所得激活率差异不显著(46.00%vs 40.38%,P>0.05),但显著高于20 mmoL/L SrCl2的激活率(46.00%vs 24.62%,P<0.05);将10 mmoL/L SrCl2激活处理6 h后得到的激活胚胎分别以DMEM培养液和LIF+DMEM培养液培养48 h,其桑葚胚分化率分别为44.00%及84.62%,组间差异显著(P<0.05)。因此,宜采用10 mmoL/L SrCl2激活去透明带MⅡ期卵母细胞,并移入到10 ng/mL LIF+DMEM培养液进行体外培养。  相似文献   

6.
为探索简化的核移植程序,本研究分析不同成熟培养时间、去核过程中紫外光照时间、融合电压强度、激活剂种类、不同培养方法对绵羊去透明带卵母细胞核移植的影响。结果表明:卵母细胞成熟培养18~19 h后去除透明带,其极体排出和附着效果最佳。采用1.9 kV/cm直流电压融合去核卵母细胞与颗粒细胞,融合率为88.2%,效果最好。离子霉素对重构胚具有较好的激活效果,卵裂率为82.1%,囊胚率为10.4%;压制WOW(s孔中孔)发育组卵裂率和囊胚发育率与四孔板培养组相比无显著差异,但卵裂率和囊胚发育率并不高;去除透明带的绵羊卵母细胞采用衰减1/4的UV照射10 s辅助去核后,卵裂率为35.6%,但重构胚未能发育至囊胚。结果显示,通过去透明带辅助显微操作去核的方法进行的绵羊体细胞克隆程序较易掌握。  相似文献   

7.
为探讨不同去核方法对猪手工克隆(HMC)重构胚发育效果的影响,本研究比较了盲切法,第一极体(Pb1)定位法及脱羰秋水仙碱(DM)辅助去核法3种不同的去核方法的去核效率及HMC胚胎发育的影响。结果表明:第一极体定位法和DM辅助去核法的整体去核效率显著高于盲切法去核法(P0.05);应用0.4μg/m L DM处理卵母细胞60 min的突起率、整体去核效率显著高于其他浓度和时间处理组(P0.05);DM辅助去核与pb1定位去核法2种不同去核方法对HMC重构胚的发育效果的影响差异不显著。本研究表明,添加适量的DM可以提高徒手克隆去核效率,且对后期重构胚发育没有显著影响。  相似文献   

8.
手工克隆(handmade cloning, HMC)是在传统克隆技术的基础上发展出的一种体细胞核移植技术,作为纯手工操作技术,每一步骤的操作细节都影响着HMC的效率及重构胚胎发育能力。本试验针对HMC生产克隆猪胚胎的3个关键步骤:透明带消化、手工切割去核与无透明带重构胚的体外培养展开研究。结果显示,猪卵母细胞透明带以3.3 mg/mL链酶蛋白酶适度消化(10~15 s),在切割去核时卵母细胞死亡率显著低于透明带的过度(高于15 s)消化,死亡率分别为(3.22±1.08)%和(31.45±2.10)%;当透明带消化时间不足(少于10 s),不能被切割去核的猪卵母细胞显著升高,不可切割率分别为(18.25±4.22)%和(0.57±0.40)%。另外,"铡刀式"操作更适用于手工切割去核,其操作要点对成功获得无核半卵及其胞质含量非常重要。HMC无透明带重构胚体外培养时,孔深约250μm、孔径约300μm的微孔技术(well of wells, WOWs)有利于克隆胚胎发育。本研究优化了HMC操作的关键步骤,为提高生产克隆猪胚胎效率奠定了基础。  相似文献   

9.
研究用细胞质内注射法构建重组胚,比较了离子霉素和乙醇预激活供体细胞和去核卵母细胞对重组胚卵裂和体外发育的影响。结果表明:与未经处理的对照组相比,离子霉素预激活供体细胞对重组胚的卵裂率和囊胚发育率有所提高;而供体细胞和去核卵母细胞同时用离子霉素预激活,重组胚的卵裂率无明显提高,囊胚发育率下降;用离子霉素或乙醇预激活去核卵母细胞,对重组胚的卵裂和发育无明显影响。  相似文献   

10.
卵母细胞的孤雌激活是研究哺乳动物受精机制和发育机理的有效方法,也是细胞核移植、显微注射受精技术、孤雌胚胎干细胞等研究内容中的重要环节。本试验分别用乙醇、SrCl2、钙离子载体A23187对小鼠卵母细胞进行单独孤雌激活,并分别与6-DMAP联合运用,对小鼠卵母细胞进行联合孤雌激活。结果显示:(1)不同激活剂单独或联合激活,对卵母细胞的激活率有显著影响(P〈0.05),SrCl2组的激活率最高(92%~94%);(2)相同激活剂对卵母细胞孤雌囊胚的发育率在单独激活组(SrCl2组,18%)和联合激活组(SrCl2+6-DMA组,53%)中存在显著差异(P〈0.05);(3)相同激活剂对卵母细胞二倍体率在单独激活组(钙离子载体A23187组,21%)和联合激活组(钙离子载体A23187+6-DMA组,77%)中均存在显著差异(P〈0.05)。结果表明:(1)SrCl2可以对小鼠卵母细胞进行有效的孤雌激活;(2)联合激活法可以显著提高孤雌卵母细胞的囊胚发育率;3、6-DMAP可以抑制第二极体排出,显著提高孤雌激活卵母细胞的二倍体率。  相似文献   

11.
The present study was conducted to demonstrate the spindle formation and behavior of chromosomes and microtubules during first division in reconstructed rat embryos produced by somatic cell nuclear transfer (SCNT) with cumulus cell nuclei. To demonstrate the effect of oocyte aging after ovulation on the cleavage of SCNT embryos, micromanipulation was carried out 11, 15 and 18 h after injection of hCG. SCNT oocytes were activated by incubation in culture medium supplemented with 5 microM ionomycin for 5 min followed by treatment with 2 mM 6-dimethylaminopurine (6-DMAP) in mR1ECM for 2-3 h. For immunocytochemical observation, the SCNT embryos were incubated with monoclonal anti-alpha-tubulin antibody and then fluorescein isothiocyanate (FITC)-conjugated goat anti-mouse IgG. Cleavage rates were significantly higher for oocytes collected after 15 and 18 h rather than for those collected 11 h after injection of hCG (56 and 53%, respectively vs. 28%; P<0.05). Premature chromosome condensation occurred before activation of the SCNT oocytes, but adequate spindle formation was only rarely observed. The distribution of microtubules in SCNT embryos after activation was different from those of fertilized and parthenogenic oocytes, i.e., a dense microtubule organization shaped like a ring was observed. Eighteen to 20 h post-activation, most SCNT embryos were in the 2-cell stage, but no nucleoli were clearly visible, which was quite different from the fertilized oocytes. In addition, first division with and without small cellular bodies containing DNA was observed in the rat SCNT embryos in some cases. The present study suggests that reorganization of transferred nuclei in rat SCNT embryos may be inadequate in terms of formation of the mitotic assembly and nucleolar reorganization.  相似文献   

12.
试验根据猪卵丘-卵母细胞复合体(COCs)的颗粒细胞层数,把COCs分成A、B、C和D级,A、B级用于体外分别培养24、32、38、44、48和54 h,C级用于体外分别培养24、32、38、44、48、54和60 h,观察它们不同时间排出极体数,然后将排出极体的卵母细胞孤雌激活。结果发现,A和B级COCs培养48 h时成熟率最高(83.2%和78.0%),明显高于同级水平培养24、32和38 h的成熟率;不同级别COCs体外培养相同时间,A与B级成熟率差异不显著(P>0.05),但二者与C级的成熟率差异显著(P<0.05);体外培养48 h COCs卵裂率最高(81.7%),与培养38 h前的卵裂率差异显著(P<0.05)。结果表明,A、B级卵母细胞更适于体外培养,能获得高的成熟率和卵裂率,COCs周围颗粒细胞对卵母细胞的成熟有显著影响;COCs培养38 h之前,部分虽能看到极体,但激活后卵裂率极低,说明卵母细胞并未真正成熟,通常通过排出极体判断卵母细胞成熟是不够准确的,COCs体外培养44~48 h是成熟的最佳时期,能为体细胞核移植提供大量优质的MⅡ期卵母细胞。  相似文献   

13.
Enucleation of a recipient oocyte is an important essential process in the procedure of somatic cell nuclear transfer (SCNT). The present study investigated a method for the improvement of enucleation efficiency. Oocytes were denuded of cumulus cells before the completion of nuclear maturation (pre-denuded) after 12 h of culture at MI stage and subsequently cultured for additional 6 h until the completion of nuclear maturation and extrusion of the first polar body (PB1). The extrusion rate of PB1 was not significantly different in the pre-denuded oocyte group, compared with control oocyte group matured for 18 h. However, the number of oocytes showing the metaphase II (MII) located just underneath the PB1 was significantly higher (p<0.05) in the pre-denuded oocyte group than those in control oocyte group. To test the effect of pre-denuding on the enucleation rate and developmental potential of embryos to blastocyst stage, subsequent somatic cell nuclear transfer comparisons were made with three different methods of enucleation at MII stage using vital dyes (demicoline and Hoescht) or the PB1 (blind enucleation) to localize the chromosome plate. Enucleation rate of the oocytes with demicoline, Hoechst and pre-denuding enucleation groups were significantly higher (p<0.05) than those of blind enucleation groups. However, cleavage rate to two-cell stage and, developmental rate to blastocyst and hatched blastocyst stage, the mean numbers of total and ICM cells in the SCNT embryos with Hoechst enucleation groups were significantly decreased (p<0.05), compared to those of blind, demicoline and pre-denuding enucleation groups. Moreover, the level of telomerase activity was also significantly (p<0.05) decreased in SCNT blastocysts of Hoechst enucleation group, compared to those of blind, demicoline and pre-denuding enucleation groups. Taken together, pre-denuding enucleation group using pre-denuded oocytes was a useful and simple enucleation method for bovine SCNT embryos.  相似文献   

14.
In mouse somatic cell nuclear transfer (SCNT), polyvinylpyrrolidone (PVP) is typically included in the nuclear donor injection medium. However, the cytotoxicity of PVP, which is injected into the cytoplasm of oocytes, has recently become a cause of concern. In the present study, we determined whether bovine serum albumin deionized with an ion-exchange resin treatment (d-BSA) was applicable to the nuclear donor injection medium in SCNT as an alternative to PVP. The results obtained showed that d-BSA introduced into the cytoplasm of an enucleated oocyte together with a donor nucleus significantly enhanced the rate of in vitro development of cloned embryos to the blastocyst stage compared with that of a conventional nuclear injection with PVP in SCNT. We also defined the enhancing effects of d-BSA on the blastocyst formation rate when d-BSA was injected into the cytoplasm of oocytes reconstructed using the fusion method with a hemagglutinating virus of Japan envelope before oocyte activation. Furthermore, immunofluorescence experiments revealed that the injected d-BSA increased the acetylation levels of histone H3 lysine 9 and histone H4 lysine 12 in cloned pronuclear (PN) and 2-cell embryos. The injection of d-BSA before oocyte activation also increased the production of cloned mouse offspring. These results suggested that intracytoplasmic injection of d-BSA into SCNT oocytes before oocyte activation was beneficial for enhancing the in vitro and in vivo development of mouse cloned embryos through epigenetic modifications to nuclear reprogramming.  相似文献   

15.
To improve the efficiency of somatic cell nuclear transfer (SCNT) in sheep, we investigated the effects of recipient oocyte source, number of transferred embryos and season on the pregnancy and live lamb rates for sheep somatic cell nuclear transfer embryos. Follicle‐stimulating hormone (FSH)‐stimulated ovaries produced significantly more oocytes both in total and of suitable quality for maturation culture than those without FSH treatment (from slaughterhouse). However, their in vitro maturation rates were similar. Embryos were reconstructed using adult fibroblast cells into enucleated MII oocytes. The pregnancy and term rates were significantly higher in the FSH‐stimulated group than in the slaughterhouse one. Oocytes from FSH‐stimulated ovaries were enucleated as recipient cytoplasm for nuclear transfer in the following experiments. The transfer of 7–9 and 11–13 embryos produced significantly higher pregnancy rates than that of six embryos. However, the former groups exhibited similar live lamb rates. FSH‐stimulated ovaries produced significantly more oocytes in November and December (winter) than in May to July (summer), but the associated maturation rate did not increase. Pregnancy and term rates were significantly higher when transfer occurred in winter than in summer. In conclusion, FSH treatment produced significant benefit regarding the number and quality of collected oocytes and also for the pregnancy and live lamb rates for reconstructed embryos. However, the transfer of an appropriate number of embryos (7–13) and at an appropriate season (winter) increased pregnancy and term rates.  相似文献   

16.
[目的] 探索不同来源卵母细胞对体细胞核移植(SCNT)重构胚的发育能力及发育潜能关键蛋白表达水平的影响。[方法] 试验分为活体采卵(OPU)和屠宰场(SLH)卵巢2组,OPU组用超声波活体采卵仪穿刺抽吸10头非泌乳期经产水牛卵巢的卵泡采卵,SLH组从屠宰场卵巢抽吸卵泡采卵。获得的卵母细胞分别进行体外成熟,体外成熟22~24 h后,吹打去除卵丘细胞,挑选具有第一极体的卵母细胞,去核后与水牛耳部成纤维细胞进行SCNT,分别统计SCNT重构胚的融合率、分裂率和囊胚率,用免疫荧光检测2种SCNT重构胚的E-钙黏蛋白(E-cadherin)和转录因子Sox2蛋白的表达水平。[结果] OPU组卵母细胞成熟率及其SCNT重构胚的囊胚率均显著高于SLH组(P<0.05),但2组SCNT重构胚的融合率和分裂率均无显著差异(P>0.05);免疫荧光结果显示,E-cadherin蛋白定位于细胞膜上,Sox2蛋白分布在细胞核膜及细胞质中,OPU组SCNT重构胚中E-cadherin和Sox2的表达水平均显著高于SLH组(P<0.05)。[结论] 活体采集的水牛卵母细胞更适合用于SCNT重构胚的构建。  相似文献   

17.
This study was carried out to determine whether culture media reconstructed with bovine enucleated oocytes and the expression pattern of Oct-4 could support dedifferentiaton of monkey fibroblasts in interspecies cloned monkey embryos. In this study, monkey and bovine skin fibroblasts were used as donor cells for reconstruction with bovine enucleated oocytes. The reconstructed monkey interspecies somatic cell nuclear transfer (iSCNT) embryos were then cultured under six different culture conditions with modifications of the embryo culture media and normal bovine and monkey specifications. The Oct-4 expression patterns of the embryos were examined at the two-cell to blastocyst stages using immunocytochemistry. The monkey iSCNT embryos showed similar cleavage rates to those of bovine SCNT and bovine parthenogenetic activation (PA). However, the monkey iSCNT embryos were not able to develop beyond the 16-cell stage under any of the culture conditions. In monkey and bovine SCNT embryos, Oct-4 could be detected from the two-cell to blastocyst stage, and in bovine PA embryos, Oct-4 was detectable from the morula to blastocyst stage. These results suggested that bovine ooplasm could support dedifferentiation of monkey somatic cell nuclei but could not support embryo development to either the compact morula or blastocyst stage. In conclusion, we found that the culture conditions that tend to enhance monkey iSCNT embryo development and the expression pattern of Oct-4 in cloned embryos (monkey iSCNT and bovine SCNT) are different than in bovine PA embryos.  相似文献   

18.
Interspecies cloning may be a useful method to help conserve endangered species and to study nuclear-cytoplasm interaction. The present study investigated in vitro development of goral (Naemorhedus goral) intergeneric nuclear transfer embryos produced by fusing goral fibroblasts with enucleated metaphase II (MII) bovine oocytes. After two to five passages, serum-starved or non-starved goral skin fibroblast cells were transferred into enucleated MII bovine oocytes. Couplets were electrically fused and chemically activated, and then cultured in either modified synthetic oviduct fluid (mSOF) or tissue culture medium-199 (TCM-199) supplemented with 10% FBS. Serum starvation of donor cells did not affect the fusion rate and or development to of cells to the two-cell stage, to more than 9-cells, or to morulae, regardless of culture medium. Three blastocysts from 202 fused embryos were obtained when embryos reconstructed with non- serum- starved donor cells were cultured in mSOF. However, no blastocysts were obtained when the embryos reconstructed with serum-starved donor cells were cultured in mSOF. The total cell number of goral intergeneric embryos averaged 130.3 (range 105-180). In conclusion, this study demonstrated that bovine oocytes can support blastocyst development after intergeneric SCNT with goral fibroblasts.  相似文献   

19.
The low viability of embryos reconstructed by somatic cell nuclear transfer (SCNT) is believed to be associated with epigenetic modification errors, and reduction of those errors may improve the viability of SCNT embryos. The present study shows the effect of trichostatin A (TSA), a strong inhibitor of histone deacetylase, on the development of murine SCNT embryos. After enucleation and nuclear injection, reconstructed murine oocytes were activated with or without TSA for 6 hr (TSA-6 hr). After activation, TSA treatment was extended to 3 hr (TSA-9 hr), 5 hr (TSA-11 hr) and 18 hr (TSA-24 hr) during culture. As a result, the SCNT embryos in the TSA-11 hr group showed a remarkably higher blastocyst rate (21.1%) when compared with the nontreated embryos (3.4%), while the concentration of TSA did not significantly affect embryonic development. The expressions of histone deacetylase (HDAC1 and HDAC2) and DNA methylation (DNMT3a and DNMT3b) genes decreased in the TSA-11 hr and TSA-24 hr groups, while there was an increase in the expression of histone acetyltransferase (P300 and CBP), pluripotency (OCT4 and NANOG) and embryonic growth/trophectoderm formation (FGF4)-related genes in the same groups. The expression of CDX2, a critical gene for trophectoderm formation was upregulated only in the TSA-24 hr group. Our results show that TSA treatment during the peri- and postactivation period improves the development of reconstructed murine embryos, and this observation may be explained by enhanced epigenetic modification of somatic cells caused by TSA-induced hyperacetylation, demethylation and upregulation of pluripotency and embryonic growth after SCNT.  相似文献   

20.
体细胞核移植(somatic cell nuclear transfer,SCNT)是一种能将已分化的体细胞重编程为全能胚胎的繁殖生物技术,在良种扩繁、濒危物种保护和治疗性克隆等方面有着广泛的应用前景,但极低的克隆效率、克隆动物胎盘异常、出生后胎儿畸形等严重限制了该技术的实际应用。造成克隆效率低和胚胎发育异常的主要原因是供体核表观遗传重编程错误或不完全。1958年,将非洲爪蟾(Xenopus laevis)幼体肠细胞核移入去核卵母细胞,获得了第1例SCNT动物个体;1986年,通过电融合1个卵裂球与去核卵母细胞成功获得了3只存活的羔羊;1997年,将成年母羊的乳腺上皮细胞与去核卵细胞电融合,获得首个SCNT哺乳动物"多利",开启了克隆时代,目前牛、小鼠、山羊、猪、欧洲盘羊、家兔、家猫、马、大鼠、骡子、狗、雪貂、狼、水牛、红鹿、单峰骆驼、食蟹猴等相继成功克隆,其中最引人瞩目的是2018年食蟹猴的成功克隆。作者通过将SCNT胚胎与受精胚胎的发育进行对比,阐述了SCNT过程中DNA甲基化、组蛋白修饰、基因组印迹、染色体状态等的重编程过程和缺陷,并从表观修饰剂、组蛋白去甲基化酶、抑制Xist表达、补充鱼精蛋白和精子RNA方面探讨单独或联合消除表观遗传重编程障碍对克隆效率的影响。随着低样本量测序技术的发展和完善,人们能够在SCNT胚胎中检测到更详细的全基因组表观遗传修饰图谱,进一步揭示SCNT胚胎表观遗传重编程中的缺陷,为提高克隆效率提供了线索。通过上述内容的阐述,希望为后续开发联合消除多种表观遗传障碍而提高克隆效率的策略和思路。  相似文献   

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