供体细胞对哺乳动物体细胞核移植的影响

哺乳动物体细胞核移植技术(克隆)在农业、生物技术、医药生产和濒危动物保护等方面具有很大的潜力和应用价值,已成为目前发育生物学研究的重要方法.文章依据近年来国内外在动物克隆技术方面的资料,分析了供体细胞类型、供体细胞动物年龄、供体细胞所处细胞周期、体外传代次数以及供体动物性别等因素对克隆动物效率的影响及可能原因.     

基因打靶用于哺乳动物体细胞核移植技术研究进展

哺乳动物体细胞核移植技术以其供核效率高而在动物克隆技术中占有明显的优势；基因打靶技术通过外源DNA与染色体DNA间的重组可达到定点修饰，改造基因组的目的，它与体细胞核移植技术相结合具有巨大的技术优势和广阔的应用前景。将为畜牧生产和医学生物学的研究带来前所未有的价值。     

供体细胞种类及性别对猪体细胞核移植效果的影响

本研究通过比较胎儿成纤维细胞、颗粒细胞、卵丘细胞和不同性别猪胎儿成纤维细胞的核移植效果,探讨供体细胞的种类及性别对猪体细胞核移植重构胚胎发育潜力的影响。结果表明:胎儿成纤维细胞的融合率(64.74%)高于颗粒细胞的融合率(51.05%)和卵丘细胞的融合率(56.89%),但3种细胞的卵裂率及囊胚率差异不显著(P>0.05);胎儿成纤维细胞、颗粒细胞和卵丘细胞均可作为供体细胞用于构建猪体细胞核移植的重构胚。雄性胎儿成纤维细胞核移植重构胚的融合率和分裂率与雌性胎儿成纤维细胞重构胚的融合率和分裂率相比差异不显著(P>0.05),但雄性胎儿成纤维细胞核移植重构胚的囊胚率显著低于雌性胎儿成纤维细胞核移植重构胚的囊胚率(P<0.05)。     

水牛体细胞核移植方法的研究

探讨电融合参数对水牛体细胞核移植效果的影响。体外成熟培养 22~24 h的水牛卵母细胞,在含有 5μg/mL细胞松弛素的操作液中进行去核,然后将经0 .1 mg/L Aphidicolin (APD)处理1 d, 再用0. 5% FBS培养2~9 d的水牛耳皮成纤维细胞或颗粒细胞注射到去核的卵母细胞卵周隙中,再经电融合形成重构胚。重构胚经 5μmol/L离子霉素激活处理5 min并在2 mmol/L的 6 DMAP中培养 3 h后,在含有颗粒细胞单层细胞的微滴中(30μL)培养7~9 d,观察其卵裂和胚胎发育情况。当电融合的电场强度为1 500 V·μs/mm(电压100 V/mm×脉时15μs)时,电脉冲3次,颗粒细胞核移植的融合率为 74.18%,分裂率为 71.82%,囊胚发育率为 10%,融合率显著高于2次电脉冲(52.03%,P<0. 05),卵裂率显著高于4次电脉冲(53.95%,P<0. 05);当电脉冲次数为 3 次时,电场强度为2 000 V·μs/mm的分裂率(53.54%)显著低于1 500 V·μs/mm,2 500 V·μs/mm的融合率(62.0%)和分裂率(53.23%)均显著低于1 500 V·μs/mm(P<0 .05)。采用耳皮成纤维细胞作供核的融合率(59.75%)和分裂率(57.45%)均显著低于颗粒细胞。染色体组型分析显示,66.7%的核移植胚胎具有正常的供体细胞二倍体核型。将来自1头22岁的摩拉公牛耳皮成纤维细胞的2枚冻胚移植给受体母牛,妊娠到215 d时发生流     

供体细胞和去核卵母细胞的不同预激活对体细胞核移植胚胎体外发育的影响

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。     

胎儿成纤维细胞的培养分离方法对猪体细胞核移植胚胎发育潜力的影响

研究采用不同传代的培养方法和不同方法处理及不同培养分离法探讨胎儿成纤维细胞的处理方法对猪体细胞胚胎发育潜力的影响。结果表明:(1)100%长满汇合胎儿成纤维细胞的核移植融合率高于70%～80%的胎儿成纤维细胞(P<0.05),分裂率高于血清饥饿培养的胎儿成纤维细胞(P<0.05),但囊胚率差异不显著(P>0.05);(2)猪胎儿成纤维细胞冷冻-解冻后的核移植分裂率和囊胚发育率均显著低于新鲜和4℃冷藏的细胞(P<0.05),但融合率无显著差异(P>0.05),表明猪胎儿成纤维细胞解冻后不宜直接进行核移植;(3)采用组织块法和酶消化法分离得到的胎儿成纤维细胞所构建的重构胚胎在融合率、分裂率和囊胚率方面没有显著差异(P>0.05)。表明100%长满汇合培养是较好的猪胎儿成纤维细胞培养处理方法;猪胎儿成纤维细胞解冻后不宜直接进行核移植;组织块法和酶消化法均可用于分离培养猪体细胞核移植的胎儿成纤维细胞。     

不同核移植方法对牛体细胞核移植效率的影响

以牛皮肤成纤维细胞为供体细胞,比较了电融合法和细胞质内注射法2种核移植方法对体细胞核移植效率的影响.电融合法构建重组胚的效率显著低于细胞质内注射法(47.1%比89.0%,P＜0.01);重组胚培养36 h后的裂卵率和培养8 d时囊胚发育率无明显差异(76.4%比73.2%,11.2%比12.3%;P＞0.05),但相对于操作的卵母细胞总数而言,电融合法得到的总囊胚发育率显著低于细胞质内注射法(5.6%比10.9%,P＜0.01).结果表明,用细胞质内注射法进行体细胞核移植效率更高.将发育到桑椹胚和囊胚期的95枚核移植胚胎移植到33头受体牛,其中31头受体牛在移植后第2个情期前返情;1头受体牛在移植后75 d返情,但未进行直肠检查,无法确定妊娠情况;1头受体牛在移植后60 d未见返情,直肠检查确证妊娠,93 d受体牛流产.胚胎移植结果表明,用细胞质内注射法构建的体细胞核移植胚胎至少可以维持早期妊娠.     

牛卵母细胞质内注射体细胞核移植胚的早期发育

研究牛皮肤成纤维细胞的处理方式对卵质内直接注射法构建的核移植胚胎发育的影响，同时比较了MⅡ期与TⅡ期卵母细胞作为受体的效果。结果表明：在细胞核注射前对供体细胞作低渗处理可明显提高胚胎构建的成功率和早期发育能力。牛皮肤成纤维细胞是否作G1／G0期同期化处理，对核移植胚胎的发育没有明显的影响。发现供核细胞在悬浮情况下作休眠处理，所得核移植胚胎的发育能力与贴附休眠的细胞基本相同，且悬浮休眠3d后的细胞无需再作低渗处理便可用作细胞核注射。MⅡ期或TⅡ期卵母细胞作为胞质内核注射受体，对牛体细胞核移植胚胎的早期发育没有明显影响。     

供体细胞低温冷藏处理对水牛体细胞核移植效果的影响

自1997年《自然》杂志报道克隆羊“多莉”以来,多种哺乳动物的体细胞核移植相继取得了成功。然而,体细胞核移植的技术环节繁多,各种各样的因素影响着核移植的效果,核移植的效率仍然很低(牛,<5%)[1]。核移植效率的提高有赖于各个技术环节的完善,供体细胞的准备与处理是核移植中的一个关键环节,它直接影响到核移植的效果。低温冷藏供体细胞可以减少染色体变异的可能性,亦有利于重构胚的发育。研究探讨了水牛胎儿成纤维细胞经低温冷藏处理后对核移植效果的影响。1材料与方法1.1试剂及培养液的配制研究所用的试剂除TCM-199购自G ibco公司外,其…     

Optimization of parthenogenetic activation of rabbit oocytes and development of rabbit embryo by somatic cell nuclear transfer

The present study explored a suitable parthenogenetic activation (PA) procedure for rabbit oocytes and investigated the developmental potential of somatic cell nuclear transfer (SCNT) embryos using rabbit foetal fibroblasts (RFFs). The electrical activation had the optimal rate of blastocyst (14.06%) when oocytes were activated by three direct current (DC) pulses (40 V/mm, 20 μs each) followed by 6‐dimethylaminopurine (6‐DMAP) and cycloheximide (CHX) treatment; the blastocyst rate of ionomycin (ION) + 6‐DMAP + CHX (12.07%) activation was higher than that of ION + 6‐DMAP (8.6%) activation or ION + CHX (1.24%) activation; there was no significant difference in blastocyst rate between ION + 6‐DMAP + CHX and DC + 6‐DMAP + CHX groups. The blastocyst rate of ION + 6‐DMAP + CHX‐activated oocytes in the basic rabbit culture medium (M‐199) + 10% foetal bovine serum (FBS; 14.28%) was higher than that in buffalo conditioned medium (5.75%) or G1/G2 medium (0), and the blastocyst rate was increased when M‐199 + 10% FBS was supplemented with amino acids. Refreshing culture medium every day or every other day significantly increased the blastocyst rate. Treatment of donor cells with 0.5% FBS for 3–5 days increased blastocyst rate of SCNT embryos (33.33%) than no serum starvation (22.47%) or 0.5% FBS treatment for 6–9 days (23.61%); the blastocyst rate of SCNT embryos derived from nontransgenic RFFs was higher than that derived from transgenic RFFs by electroporation. The blastocyst development ability of SCNT embryos derived from RFFs by electroporation (32.22%) was higher than that of liposome (19.11%) or calcium phosphate (20.00%) transfection, and only the embryos from electroporation group have the EGFP expression (24.44%). In conclusion, this study for the first time systematically optimized the conditions for yield of rabbit embryo by SCNT.     

水牛体细胞连续核移植的效果

为探讨水牛体细胞连续核移植的效果,以水牛胎儿成纤维细胞为核供体,进行了水牛体细胞连续核移植。结果显示,连续核移植的融合率显著高于原代核移植(87.9%vs76.2%,P<0.05),但两者之间的分裂率和囊胚率没有显著差异(P>0.05);这说明水牛体细胞核移植胚胎可被再次克隆而不降低其发育能力,水牛体细胞连续核移植是可行的。     

Evaluation of porcine urine-derived cells as nuclei donor for somatic cell nuclear transfer

BackgroundSomatic cell nuclear transfer (SCNT) is used widely in cloning, stem cell research, and regenerative medicine. The type of donor cells is a key factor affecting the SCNT efficiency.ObjectivesThis study examined whether urine-derived somatic cells could be used as donors for SCNT in pigs.MethodsThe viability of cells isolated from urine was assessed using trypan blue and propidium iodide staining. The H3K9me3/H3K27me3 level of the cells was analyzed by immunofluorescence. The in vitro developmental ability of SCNT embryos was evaluated by the blastocyst rate and the expression levels of the core pluripotency factor. Blastocyst cell apoptosis was examined using a terminal deoxynucleotidyl transferase dUTP nick end-labeling assay. The in vivo developmental ability of SCNT embryos was evaluated after embryo transfer.ResultsMost sow urine-derived cells were viable and could be cultured and propagated easily. On the other hand, most of the somatic cells isolated from the boar urine exhibited poor cellular activity. The in vitro development efficiency between the embryos produced by SCNT using porcine embryonic fibroblasts (PEFs) and urine-derived cells were similar. Moreover, The H3K9me3 in SCNT embryos produced from sow urine-derived cells and PEFs at the four-cell stage showed similar intensity. The levels of Oct4, Nanog, and Sox2 expression in blastocysts were similar in the two groups. Furthermore, there is a similar apoptotic level of cloned embryos produced by the two types of cells. Finally, the full-term development ability of the cloned embryos was evaluated, and the cloned fetuses from the urine-derived cells showed absorption.ConclusionsSow urine-derived cells could be used to produce SCNT embryos.     

Recent progress in bovine somatic cell nuclear transfer

Bovine somatic cell nuclear transfer (SCNT) embryos can develop to the blastocyst stage at a rate similar to that of embryos produced by in vitro fertilization. However, the full‐term developmental rate of SCNT embryos is very low, owing to the high embryonic and fetal losses after embryo transfer. In addition, increased birth weight and postnatal mortality are observed at high rates in cloned calves. The low efficiency of SCNT is probably attributed to incomplete reprogramming of the donor nucleus and most of the developmental problems of clones are thought to be caused by epigenetic defects. Applications of SCNT will depend on improvement in the efficiency of production of healthy cloned calves. In this review, we discuss problems and recent progress in bovine SCNT.     

影响猪体细胞核移植效果的因素

克隆技术的研究已经取得了丰硕的成果,但猪体细胞核移植还受到众多因素的制约,克隆效率仍然较低,文章针对猪体细胞核移植的各项技术环节及影响因素进行探讨与分析,以期加快猪体细胞核移植技术的研究,提高猪体细胞核移植效率,进一步促进猪体细胞核移植技术的发展和运用。     

Supplement of autologous ooplasm into porcine somatic cell nuclear transfer embryos does not alter embryo development

Somatic cell nuclear transfer (SCNT) is considered as the technique in which a somatic cell is introduced into an enucleated oocyte to make a cloned animal. However, it is unavoidable to lose a small amount of the ooplasm during enucleation step during SCNT procedure. The present study was aimed to uncover whether the supplement of autologous ooplasm could ameliorate the oocyte competence so as to improve low efficiency of embryo development in porcine SCNT. Autologous ooplasm‐transferred (AOT) embryos were generated by the supplementation with autologous ooplasm into SCNT embryos. They were comparatively evaluated with respect to embryo developmental potential, the number of apoptotic body formation and gene expression including embryonic lineage differentiation, apoptosis, epigenetics and mitochondrial activity in comparison with parthenogenetic, in vitro‐fertilized (IVF) and SCNT embryos. Although AOT embryos showed perfect fusion of autologous donor ooplasm with recipient SCNT embryos, the supplement of autologous ooplasm could not ameliorate embryo developmental potential in regard to the rate of blastocyst formation, total cell number and the number of apoptotic body. Furthermore, overall gene expression of AOT embryos was presented with no significant alterations in comparison with that of SCNT embryos. Taken together, the results of AOT demonstrated inability to make relevant values improved from the level of SCNT embryos to their IVF counterparts.     

Positive effects of treatment of donor cells with aphidicolin on the preimplantation development of somatic cell nuclear transfer embryos in Chinese Bama mini-pig (Sus Scrofa)

To optimize somatic cell nuclear transfer (SCNT) procedures in mini-pigs, the present study was designed to examine the effects of donor cell types and aphidicolin (APC) treatment on in vitro development of reconstructed embryos. Oviduct epithelial cells (OEC), ear fibroblast cells (EFC) and cumulus cells (CC) derived from mini-pigs were treated with serum starvation only or serum starvation followed by treatment of 0.1 µg/mL APC. The reconstructed embryos were cultured for 7 days to evaluate their developmental competency. Cleavage and blastocyst formation rates of reconstructed embryos derived from the OEC by APC treatment were significantly higher than the serum starvation (61.82% vs. 56.25%, 24.55% vs. 17.86%; P < 0.05). The cleavage rate from the EFC was significantly increased by APC treatment compared to serum starvation only (63.36% vs. 57.01%; P < 0.05). In the ooctyes with the CC, the reconstructed embryos could yield high blastocyst formation rate by APC treatment (29.63%; P < 0.05). In the presence of APC, CC gave rise to the highest cleavage and blastocyst formation rates among the three cell types. Therefore, our results suggest that treatment of CC with serum starvation plus APC prior to nuclear transfer is more suitable in SCNT of mini-pigs.     

不同蔗糖浓度、供体细胞保存温度和融合温度对小鼠体细胞克隆胚胎发育的影响

以昆明小鼠为实验动物,经过超数排卵后得到卵丘卵母细胞复合体(COCs),以卵丘细胞为核供体细胞,卵母细胞为核受体细胞进行核移植,分析比较了不同蔗糖浓度对小鼠卵母细胞去核时间、去核率及重构胚体外发育的影响,并探讨了供体细胞的保存温度和融合温度对重构胚体外发育的影响.结果表明,各蔗糖浓度组的去核率均达到100%,但3%、4...     

关于用动物属间体细胞核移植拯救濒临灭绝动物的研究

和克隆啮齿动物和家畜有所不同,由于濒危动物的卵母细胞的缺乏,克隆将要灭绝的物种需要具有选择性的方法,比如种属间体细胞核移植。文章以将喜马拉雅班羚体细胞注入牛卵母细胞的属间核移植后的囊胚的产生为例^[1],介绍属间核移植的具体方法.由于将要灭绝的物种总数急剧减少,并且对它们实施人工繁殖技术的报道很少。因此,人工繁殖技术、属间和种内的体细胞核移植对增加有限的濒临灭绝物种的总体和保存这个物种是一个很有潜力的办法.希望这个方法会对环境保护和濒危动物的繁衍产生一定的作用.