实验兔胞内单精子注射技术

目的 建立实验兔胞内单精子注射技术(intracytoplasmic sperm injection,ICSI).方法 实验1比较了hCG注射后不同取卵时间对ICSI胚体外发育的影响.实验 2 比较了不同的激活方式对ICSI胚体外发育的影响.实验 3 比较了不同状态的兔精子ICSI胚胎体外发育结果.结果 (1)hCG注射后14 h取卵,其卵裂率、桑椹胚率和囊胚率(82.2%、72.9%和62.2%)都比16 h(75.9%、70.0%和53.3%)的高,但是差异无显著性(P>0.05);18 h取的卵注射后不能卵裂.(2)机械刺激组和离子霉素 6-DMAP组,ICSI后其卵裂率分别为82.2%和81.1%(P>0.05),桑椹胚率分别为72.9%和66.2%(P>0.05),囊胚率分别为51.3%和62.3%(P<0.05),机械刺激组和离子霉素组之间卵裂率和桑椹胚率差异无显著性,但是囊胚率差异有显著性.(3)新鲜精子组和冻融活精子组卵裂率(81.1%和68.8%)和囊胚率(62.3%和40.4%)差异有显著性(P<0.05),而桑椹胚率(66.2%和61.9%)差异无显著性(P>0.05).结论 精子冷冻前后,通过ICSI所得的桑椹胚均能孵化,表明已初步建立了实验兔的ICSI技术.     

兔受精卵显微注射外源基因外体外培养的卵裂发育

从超数排卵的１４只母兔获得４３８枚受精卵,卵龄１６￣２２小时。显微操作在带微分干涉和相差的Ｎｉｋｏｎ倒置显微镜下进行。注射针的尖端外径０．５ｕｍ,离尖端４０和８０ｕｍ处的外径分别为４．２和６．５ｕｍ。注射用外源基因是绵羊生长激素基因与ＭＴ－１启动基因藕连的线状ＤＮＡ溶液（１ｎｇ／ｕｌ）。１４０枚注射的受精卵和未注射的１４５枚受精卵（对照）,在Ｈａｍ／ｓＦ－１０培养液（补充生长因子）中培养（３８℃）     

6-DMAP和胚胎干细胞代数对异种重构卵体外发育的影响(简报)

核移植技术已经广泛应用于动物克隆,但是克隆动物的成活率仍然很低。许多克隆胚胎死于妊娠期,少部分能发育到期,正常出生,但多数在出生后由于心肺和消化道的问题,很快就夭折,有些克隆动物有异常表型,如出生时体重和胎盘过大等。研究发现,在同种克隆动物实验中用胚胎干细胞(Embryonic stem cell,ES细胞)作为核供体,发育到期的克隆动物比例明显高于体细胞,并且用杂交一代的小鼠ES细胞为核供体,绝大多数克隆仔     

乙醇对着床前小鼠胚胎体外发育的影响

用含不同浓度乙醇的Whitten氏培养液对小鼠2细胞、4细胞、8细胞和桑椹期胚胎分别进行体外培养,研究了乙醇对小鼠不同发育时期胚胎体外发育的影响。首先利用含0、0．1％、0．5％、1．0％、1．5％、2．0％、3．0％、5．0％和10．0％乙醇的Whitten氏培养液对2细胞胚胎进行培养,发现小鼠2细胞胚胎对培养液中乙醇浓度的耐受极限在1．5％左右。然后又用含1％和3％乙醇的Whitten氏培养液分别对小鼠2细胞、4细胞、8细胞和桑椹期胚胎进行培养。结果发现：含1％乙醇的培养液对于8细胞胚胎和桑椹胚的囊胚形成有促进作用,而在2细胞和4细胞胚胎中则影响不明显。3％乙醇则对各期胚胎均有不同程度的抑制作用,但随着胚胎发育其对乙醇的耐受力逐渐增强。     

兔2—细胞胚胎电融合及其融合胚体外发育的研究

本文对兔２－细胞胚胎卵裂球电融合制作四倍体胚胎的适宜条件进行了研究。电场强度为２．０千伏／厘米,脉冲时程为４０微秒时,可获得最好的融合率（６８．９－１００％,平均为７７．３％）及融合胚发育率（７４．５％）,该发育率与受精卵体外囊胚发育率（７９．３％）相似。对于电融合及融合胚发育,非电解质溶液（０．３ｍｏｌ／Ｌ甘露醇＋０．１ｍｍｏｌ／Ｌ氯化钙＋０．１ｍｍｏｌ／Ｌ硫酸镁）优于电解质溶液。融合后,７２．     

兔受精卵显微注射外源基因后体外培养的卵裂发育

从超数排卵的１４只母兔获得４３８枚受精卵,卵龄１６～２２小时．显微操作在带微分干涉和相差的Ｎｉｋｏｎ倒置显微镜下进行．注射针的尖端外也０．５μｍ,离尖端４０和８０μｍ处的外径分别为４．２和６．５μｍ．注射用外源基因是绵羊生长激素基因与ＭＴ－１启动基因藕连的线状ＤＮＡ溶液（１ｎｇ／μｌ）．１４０枚注射的受精卵和未注射的１４５枚受精卵（对照）,在Ｈａｍ’ｓＦ—１０培养液（补充生长因子）中培养（３８℃,５％的ＣＯ２）．结果,培养４８小时后,注射组卵裂发育率分别是：未卵裂７．９％（１１／１４０）、卵裂至２～４细胞期１１．０％（１６／１４０）、卵裂至８～１６细胞期８０．７％（１１３／１４０）．对照组相应的卵裂率分别是４．１％（６／１４５）、１２．４％（１８／１４５）和８３．４％（１２１／１４５）．两组卵裂发育率相近．本实验的显微操作对注射后卵的发育没有产生明显的伤害影响．     

6—DMAP和胚胎干细胞代数对异种重构卵体外发育的影响（简报）

The development of reconstructed oocytes and the survival rate of cloned animal were affected by many factors during nuclear transfer. The genetic constitution and the genetic state of donor nucleus were proposed to be primary factors, which affected the survival rate of cloned animal. In addition, the survival rate of cloned animal might be influenced by nuclear transfer technique itself and passages of donor cells as well as the activation methods of oocytes. We reconstructed oocytes with outbreeding Kunming albino mouse ES cells and enucleated rabbit oocytes, and analyzed the effects of the passages of ES cells and 6-DMAP on the development of interspecific reconstructed oocytes. The interspecific reconstructed ES-rabbit oocytes were activated either by combined two set electric pulses and 6-DMAP or by two set electric pulses alone. The rate of cleavage was significantly higher for the group (86.2%) treated with 6-DMAP than the group (64.2%, P < 0.05) treated with electric pulses only, and the rate of blastocysts was 17.0% and 13.4% respectively, which were not significantly different between two groups. When ES cells that had been passed for 24 and 14 generations were used as donors, the cleavage rates of the reconstructed oocytes were 88.5% and 82.1%, respectively (P > 0.05), and the rates of blastolation were 16.7% and 15.4%, respectively (P > 0.05). The results show that 6-DMAP increases the cleavage rate of reconstructed oocytes derived from ES cells, and affects slightly the developmental rate of blastocysts. There are no differences when high passage and low passage ES cells are used as nuclear donors.     

不同防冻剂对兔胚胎干细胞慢速冷冻保存的影响

干细胞冷冻保存是干细胞研究和临床应用中的必需技术。为提高兔胚胎干细胞在慢速冻存过程中的保存效果,比较了二甲基亚砜(DMSO)和乙二醇(ethylene glycol,EG)对兔胚胎干细胞冷冻保护效果。对冷冻复苏后的细胞进行台盼蓝染色,并研究其胚胎干细胞分子特性,结果表明DMSO比EG具有更好的冷冻保护效果。再在以10%DMSO为基础的防冻液中添加膜稳定剂海藻糖(trehalose)或谷氨酰胺(glutamine),细胞冷冻复苏后结果显示,谷氨酰胺对兔胚胎干细胞有明显的冷冻保护作用,使细胞存活率从71%提高到83.7%。当谷氨酰胺浓度为0、5、10、20、40mmol/L分别加入防冻液中后,20mmol/L的谷氨酰胺具有最佳的冷冻保护效果。以上结果得出兔胚胎干细胞慢速冷冻的防冻液改进配方为:在胚胎干细胞培养液中添加10%DMSO 20mmol/L谷氨酰胺。     

不同年龄和FSH对牛活体取卵体外发育潜能的影响

不同年龄和FSH对牛活体取卵体外发育潜能的影响@苏雷$中国科学院昆明动物研究所! 中国 昆明650223 @和协超$中国科学院昆明动物研究所! 中国 昆明650223 @司维$中国科学院昆明动物研究所! 中国 昆明650223 @季维智$中国科学院昆明动物研究所! 中国 昆明650223     

SD大鼠胞质内单精注射技术方法的建立

目的建立SD大鼠胞质内单精注射操作程序。方法和结果实验1：用直径为7～10μm和2-4μm的注射针以及相应的注射方法进行大鼠ICSI,ICSI后卵母细胞存活率（30．5％vs．61．3％）和卵裂率（12．5％vs．51．1％）均差异显著（P〈0．05）;实验2：分别在hCG后14h、16h和18h取卵进行ICSI,三组存活率（77．4％、74．1％vs．69．6％）差异不显著（P〉0．05）;14h和16h组的卵裂率（60．8％、56．0％vs．31．3％）与18h组差异显著（P〈0．05）;实验3：用不同的显微操作液H-mR1CM和H-mKRB进行大鼠ICSI,结果卵存活率相近（79．2％vs．75．9％）,卵裂率（70．5％vs．74．7％）差异不显著（P〉0．05）,但8-细胞发育率（43．5％vs．61．9％）差异显著（P〈0．05）,囊胚发育率差异极显著（P〈0．01）。结论大鼠ICSI时在注射hCG后14～16h取卵最佳,采用2—4pan直径的注射针、H—mKRB作为操作液更有利于卵的发育。     

Viability of ICSI oocytes after caffeine treatment and sperm membrane removal with Triton X-100 in pigs

Non-adequate decondensation of injected sperm nucleus is one the main problems of intracytoplasmic sperm injection (ICSI) in porcine. With the aim of improving pronuclear formation, the effects on activation and embryo development rates of 0.1% Triton X-100 (TX) sperm pre-treatment for membrane removal and/or 5 mM Caffeine (CAF) addition in oocyte manipulating and culture medium for 2 h after ICSI or artificial activation were studied. The effects of 4 different Ca²⁺ concentrations contained in the injection medium on embryo development after sham injection were also analysed. In Experiment 1, no significant effect on cleavage or blastocyst rate was detected independently of Ca²⁺ concentration contained in the injection medium. In Experiment 2, oocytes injected with TX pre-treated sperm showed a significant higher rate of male pronuclear formation in comparison with oocytes from control group (2PN; 54.1 vs 36.6%). However, no differences on in vitro embryo development, cleavage or blastocyst rates were observed. In Experiment 3, oocytes treated with CAF during and after micromanipulation and injected with sperm pre-treated with TX had a significantly lower oocyte activation rate than any other experimental groups (25.7 vs 56.3-66.3%). No differences were observed in cleavage rates among different experimental groups. However, the CAF group showed a higher blastocyst rate significantly different from TX+CAF group (12.0 vs 1.9%, respectively). In a second approach, the effect of electric field strengths and CAF treatments on oocyte activation was studied. In Experiment 4, oocytes submitted to 0.6 kV/cm showed significant higher activation rates than 1.2 kV/cm ones regardless of the caffeine treatment (83.7 vs 55.9% and 75.7 vs 44.3%; in control and caffeine groups, respectively). No effect of caffeine treatment was observed in any experimental group. In conclusion, TX sperm treatment before ICSI without an additional activation procedure improved male pronuclear formation, but did not improve embryo development until blastocyst stage. No significant effect of caffeine was found when sperm was not treated with TX, although in membrane absence caffeine avoided oocyte activation and embryo development. Finally, caffeine had no effect on female pronuclear formation regardless of electric field strengths applied to the parthenogenetic activation.     

Nitric oxide extends the oocyte temporal window for optimal fertilization

Deteriorating oocyte quality is a critical hurdle in the management of infertility, especially one associated with advancing age. In this study, we explore the role of nitric oxide (NO) on the sustenance of oocyte quality postovulation. Sibling oocytes from superovulated mice were subjected to intracytoplasmic sperm injection (ICSI) with cauda-epididymal spermatozoa following exposure to either the NO donor, S-nitroso-N-acetylpenicillamine (SNAP, 0.23 microM/min), an NO synthase (NOS) inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME, 1 mM), or an inhibitor of soluble guanylyl cyclase (sGC), 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ, 100 microM); while their sibling oocytes were subjected to ICSI either before (young) or after culture for the corresponding period of time (old). Outcomes of normal fertilization, cleavage, and development to the morula and blastocyst stages were compared. Embryos from each subgroup were also subjected to TUNEL assay for apoptosis. A significant deterioration in the ability of the oocytes to undergo normal fertilization and development to morula and blastocyst stages occurred among oocytes aged in culture medium compared to their sibling cohorts subjected to ICSI immediately after ovulation (P<0.05). This deterioration was prevented in oocytes exposed to SNAP. In contrast, exposure to L-NAME or ODQ resulted in a significant compromise in fertilization and development to the morula and blastocyst stages (P<0.05). Finally, apoptosis was noted in embryos derived from aged oocytes and those exposed to L-NAME or ODQ, but not in embryos derived from young oocytes or oocytes exposed to SNAP. Thus, NO is essential for sustenance of oocyte quality postovulation.     

Effects of liquid preservation of sperm on their ability to activate oocytes and initiate preimplantational development after intracytoplasmic sperm injection in the pig

The objective of this study was to clarify the effects of liquid preservation conditions on the ability of pig sperm to activate oocytes, form a male pronucleus, and initiate preimplantational development of embryos after intracytoplasmic sperm injection (ICSI). Porcine ejaculates were preserved at 4, 14, and 24 °C for up to 48 h, and then damage to the plasma membrane, morphologic changes of the acrosome, and the amount of phospholipase Cζ (PLCζ) in the sperm were assessed by SYBR-14/propidium iodide staining, fluorescein isothiocyanate-conjugated peanut agglutinin staining, indirect immunofluorescence, and Western blots, respectively. The proportion of sperm with a disintegrated plasma membrane or damaged acrosome increased in all samples as the duration of preservation increased, although the time courses of the increases varied among preservation temperatures. The immunolocalization and immunoreactivity of PLCζ in the sperm showed its reduction concurrent with disintegration of the plasma membrane and acrosome. Rates of oocyte activation, male-pronuclear formation, and blastocyst formation after ICSI using sperm preserved for 18 h at 24 °C (78%, 62%, and 35%, respectively) and for 48 h at 14 °C (63%, 53%, and 28%, respectively) were significantly higher than those of any other sperm sample. We concluded that the damage to the plasma membrane and acrosome, and a sufficient amount of PLCζ in the sperm head, enhanced successful oocyte activation, fertilization, and early development of the oocytes after ICSI. Moreover, we inferred that appropriate liquid preservation of sperm improved the efficiency of blastocyst production in vitro after ICSI in pigs.     

Relationship between pregnancy,embryo development,and sperm deoxyribonucleic acid fragmentation dynamics

The way the dynamics of DNA fragmentation affects the growth of embryos in real time, and effectiveness of infertility treatment using the ICSI procedure were determined in 148 couples treated with the ICSI technique. The percentage of sperm with fragmented DNA (known as the DNA fragmentation index [DFI]) in semen samples was determined at 3, 6 and 12 h. Embryo culture was assessed continuously during 12 h of observation monitoring.Statistically significant difference was found in DFI at 12 h and outcome of treatment. For the remaining time intervals, no statistically significant differences were noted. An analysis of relationship between the DFI dynamics over time at individual measurements and achievement of pregnancy, confirmed a statistically significant relationship between the rate measured at 6–12 h of observations of DFI changes (DFI 12 h%/h), and achieving pregnancy. Correlation was observed between DFI (during 0, 3, 6 and 12 h), the growth rate in DFI, and time of embryo development. A statistically significant relationship was found between the rate from the start to the end of observations of the DFI, and outcome of treatment.Intensity level regarding fragmentation of sperm DNA and its growth rate affected the time of embryo development in the ICSI procedure. The most significant prognostic factor for achieving pregnancy was intensification of sperm DNA fragmentation after 12 h.     

Cytoplasmic lipid droplets and mitochondrial distribution in equine oocytes: Implications on oocyte maturation, fertilization and developmental competence after ICSI

Lipid droplets (LDs) and mitochondria in the ooplasm are essential for energy production required for maturation, fertilization and embryo development. This study investigates the correlations between cytoplasmic LDs polar aggregation and: (1) nuclear maturation (Experiment 1); (2) mitochondrial (mt) distribution pattern and localization (Experiment 2); (3) fertilization and embryonic development after intracytoplasmic sperm injection (ICSI; Experiment 3) in equine oocytes recovered from slaughtered mares and matured in vitro. Morphologically normal oocytes were selected after culture and categorized as having polar (P) aggregation or uniform (U) distribution of LDs. In Experiment 1, the maturation rate was significantly higher in P compared with U oocytes (69%, 40/58 vs. 32%, 13/41; P < 0.001). In Experiment 2, it was observed that P and U oocytes showed heterogeneous mt distribution at comparable rates (68%, 25/37 vs. 50%, 2/4 for P and U respectively; NS). Moreover, only in 8/25 (32%) of P oocytes, LDs overlapped with mt aggregates in the area containing meiotic spindle. In Experiment 3, normal fertilization (51%, 19/37 vs. 60%, 6/10, for P and U) and cleavage rates (83%, 20/24 vs. 67%, 4/6, for P and U) did not differ between groups, also in oocytes with LDs located nearby the polar body. Overall, P aggregation of LDs was related to cumulus expansion at collection. In conclusion, in equine matured oocytes, P aggregation of LDs is related with cumulus expansion and nuclear maturation. However, it is not related with heterogeneous mt distribution and cannot be considered a predictive indicator for normal fertilization and embryo development.     

Improvement in the long-term stability of freeze-dried mouse spermatozoa by adding of a chelating agent

This study demonstrates that a small amount of chelating agent in the freeze-drying solution is necessary to prevent the deterioration of spermatozoa during freeze-drying and subsequent preservation at 4 degrees C. We freeze-dried mouse epididymal spermatozoa in the solutions containing Tris-HCl and ethylenediaminetetraacetic acid (EDTA) as a chelating agent. Spermatozoa stored for various times up to 1 year at 4 degrees C were injected intracytoplasmically into individual oocytes, and the normality of chromosomes in fertilized oocytes was analyzed. In addition, embryos derived from freeze-dried spermatozoa were transferred into recipients to determine their developmental ability. Chromosomes were maintained well when spermatozoa were freeze-dried in a solution containing 10 mM Tris-HCl and 1mM EDTA (73%), and 57% of embryos developed to term. Of embryos derived from spermatozoa stored for 1 year, 65% developed into live offspring. On the other hand, when spermatozoa were freeze-dried in a solution containing 10 mM Tris-HCl and 0 or 50 mM EDTA, spermatozoa that maintained karyotypically normal chromosomes were 64% or 22%, and only 16% or 3% of embryos were developed to term, respectively. This finding suggested that mouse spermatozoa can be freeze-dried in a simple solution containing the same composition as that used to preserve extracted DNA.