猪卵母细胞孤雌激活技术概述

孤雌激活随着近年来体细胞克隆技术的兴起而成为了又一研究热点.而猪由于其生理结构与人的相似性,所以其卵母细胞的孤雌激活更具有特别的研究价值,文章就孤雌激活的概念、机理、方法、影响因素等方面全面论述了猪卵母细胞孤雌激活的研究概况.     

不同激活条件和培养基对兔卵母细胞孤雌激活和胚胎发育的影响

对新西兰兔成熟卵母细胞在不同方式激活后的发育潜能和孤雌胚胎在不同培养体系中的发育进行了研究。结果发现电击激活和化学激活单独使用不能很好的激活兔卵母细胞,两次电击和化学激活配合使用能够较好的激活兔卵母细胞。通过比较发现B2培养基支持兔孤雌胚胎发育的能力显著高于其他培养基。试验建立了和体内受精时间过程相似的卵母细胞活化和培养系统,为兔的核移植技术优化了条件。     

猪体外成熟卵母细胞孤雌激活和胚胎培养的研究

以猪体外成熟卵母细胞为实验材料,研究了不同激活方法、激活时间以及是否添加滋养层细胞的条件对猪成熟卵母细胞体外培养的影响。结果表明,Ionomycin+6-DAMP+CB法卵裂率高,且差异显著;使用6-DMAP激活3h的卵裂率要低于4h和5h组,且差异显著;在卵裂率、8细胞率和囊胚率上,添加滋养层细胞组与未添加滋养层细胞组之间无显著差异,但添加vero细胞后效果略好。     

影响牛卵母细胞孤雌激活胚胎发育的因素

卵母细胞体外成熟后孤雌激活发育是一个新兴的研究方向,影响牛卵母细胞孤雌激活发育因素很多,国内此方面的报道较少,文中就牛卵母细胞体外成熟后孤雌激活胚胎发育的影响因素进行总结。旨在为研究体外孤雌胚发育和孤雌胚胎的培养提供参考。     

猪孤雌胚胎体外序贯培养

试验旨在探索不同培养体系和不同序贯培养法对猪孤雌胚胎体外发育的影响。采用普通培养和序贯培养2种培养方法进行猪卵母细胞的体外培养。结果表明,孤雌激活卵母细胞在NCSU23+0.4%BSA中分裂效果较好,而mTCM199+0.1%PVA则更有利于孤雌胚胎突破4细胞阻滞达到桑葚胚。在4种序贯培养中,NCSU23(0.4%BSA)+mTCM199(0.1%PVA)一组更适合于猪孤雌胚胎的体外培养。     

哺乳动物卵母细胞孤雌激活研究进展

孤雌激活是指处于第2次减数分裂中期卵母细胞不经过雄性配子的作用,而在某些理化因素的刺激下恢复并完成减数分裂,进行有丝分裂发育到胚胎的过程.卵母细胞的激活是以Ca2+为第二信使,成熟促进因子(MPF)、细胞分裂素活化蛋白激酶(MAPK)、细胞静止因子(CSF)等细胞因子综合作用的结果.卵母细胞激活是核移植的关键技术,也是研究哺乳动物受精机制及发育机理的有效方法.现介绍卵母细胞孤雌激活的机制以及卵母细胞孤雌生殖激活方法.     

亚胺环己酮对猪卵母细胞人工孤雌激活作用的研究

本文以体外成熟的猪卵母细胞为材料，以乙醇、电脉冲和氯化锶为人工刺激条件，研究了蛋白质合成抑制剂－亚胺环己酮（CHX）对猪卵母细胞的孤雌激活效果的影响。结果表明，乙醇、电脉冲和SrCl2均可使猪母细胞激活，而电脉冲的活效果最好。当分别与CHX联合使用时，激活率显著高于单独的乙醇、电脉冲或SrCl2刺激。说明，CHX与乙醇、电脉冲及SrCl2联合使用对猪IVM卵母细胞激活具有显著的协同促进作用。     

哺乳动物卵母细胞孤雌激活的研究进展

本文对哺乳动物卵母细胞孤雌激活机制、激活方法及激活效果的影响因素等作了浅要的综述和总结。     

孤雌激活的研究进展

研究哺乳动物卵母细胞的激活及其以后的孤雌胚发育,有利于探索卵母细胞的生理反应,分析理化激活和精子激活的特征,对阐明哺乳动物卵激活、受精与发育机理等,均有十分重要的意义。许多物理和化学方法可以人工激活卵母细胞。笔者对近年来孤雌激活的研究进行了综述,为寻找一种最佳的人工激活方法,进一步提高核移植技术的成功率,提供技术参考。     

胰岛素和白血病抑制因子对猪卵母细胞体外成熟和孤雌激活胚胎的影响

为探讨胰岛素(Insulin)和白血病抑制因子(Leukemia inhibit factor,LIF)对猪卵母细胞体外成熟(IVM)和猪孤雌激活胚胎(PAEs)的影响,在卵母细胞体外成熟或者胚胎培养基中添加Insulin和LIF,研究卵裂率和囊胚率的变化。结果:添加了5μg/mL Insulin后猪卵母细胞体外成熟效果显著提高,但成熟后孤雌激活发育能力与非添加组相近;而胚胎培养基中添加Insulin对孤雌胚的卵裂和囊胚的形成也没有明显促进作用;添加1 000 U/mL的LIF后,卵母细胞核成熟率没有明显提高,反而孤雌激活后囊胚率急剧下降,但对卵裂率以及囊胚总细胞数影响不大;在胚胎培养基中添加LIF后,孤雌胚的卵裂和囊胚形成并没有明显的提高。表明:Insulin对卵母细胞体外成熟有益,但是对孤雌胚胎的最佳处理程序还需要摸索;本文所采用的LIF处理对猪卵体外成熟以及孤雌胚胎体外发育没有帮助,还需要进一步研究其他浓度和处理程序对猪卵母细胞体外成熟和孤雌激活胚胎发育能力的影响。     

哺乳动物卵母细胞孤雌激活的研究进展

本文对哺乳动物卵母细胞孤雌激活机制、激活方法及激活效果的影响因素等作了浅要的综述和总结。     

有无透明带牛卵母细胞孤雌发育研究

研究探讨了不同浓度的钙离子载体(A23187)结合6-二甲氨基嘌呤(DMAP)或丁内酯Ⅰ(BL-1)激活处理对有或无透明带牛卵母细胞孤雌发育的影响。结果表明：使用A23187浓度从0．625～10．000μmol／L配合2．0mmol／L DMAP孤雌激活牛具透明带卵均能获得良好的卵裂及早期胚胎发育效果；对于去透明带卵来说．使用0．625μmol／L浓度的A23187激活效果最佳。BL-1的激活效果则明显差于DMAP；当采用0．3%PVA取代激活液中的5%血清时，BL-1的激活效率显著提高。     

Kaempferol alleviates the reduction of developmental competence during aging of porcine oocytes

Kaempferol (KAE) is a natural flavonoid present in different plant species and exhibits anti‐inflammatory, antioxidant, and anticancer therapeutic properties. In the present study, we investigated the influence and underlying mechanisms of KAE supplementation on porcine oocytes during in vitro aging. The results show that KAE treatment can alleviate the aging‐related reduction of developmental competence. We observed that the blastocyst production rate in aged oocytes treated with 0.1 μM KAE was significantly higher than in untreated aging oocytes (36.78 ± 0.86% vs. 27.55 ± 2.60%, respectively, p < .05). The KAE‐treated aging oocytes had significantly reduced levels of reactive oxygen species (p < .05). Furthermore, the mRNA levels of the embryonic pluripotency‐related genes Oct4, NANOG, and ITGA5 were significantly increased in blastocysts derived from KAE‐treated oocytes (p < .05). During excessive oocyte culture, KAE treatment maintained the mitochondrial membrane potential and reduced apoptosis; however, this was not observed in untreated aging oocytes. In conclusion, our results suggest that KAE treatment can alleviate the aging of porcine oocytes by reducing oxidative stress and improving mitochondrial function.     

小鼠卵母细胞孤雌激活试验

应用两种激活方法(乙醇和离子霉素 6-DMAP)激活和三种培养液(CZB，KSOM，M199)对90只小鼠卵母细胞进行了孤雌激活研究。结果显示，离子霉素结合6-DMAP的激活效果高于乙醇；三种培养液中，以CZB激活效果较为理想。在随后的卵母细胞发育率方面，CZB、KSOM和M199三者之间的差异极为明显，以CZB最高，KSOM次之，M199的发育率最低。     

Chitosan nanoparticles enhance developmental competence of in vitro-matured porcine oocytes

Oxidative stress is inevitable as it is derived from the handling, culturing, inherent metabolic activities and medium supplementation of embryos. This study was performed to investigate the protective effect of chitosan nanoparticles (CNPs) on oxidative damage in porcine oocytes. For this purpose, cumulus–oocyte complexes (COCs) derived from porcine slaughterhouse ovaries were exposed to different concentrations of CNPs (0, 10, 25 and 50 µg/ml) during in vitro maturation (IVM). Oocytes treated with 25 µg/ml CNPs showed significantly higher levels of GSH, along with a significant reduction in ROS levels compared to control, CNPs10 and CNPs50 groups. In parthenogenetic embryo production, the maturation rate was significantly higher in the CNPs25 group than that in the control and all other treated groups. In addition, when compared to the CNPs50 and control groups, CNPs25-treated oocytes showed significantly higher cleavage and blastocyst development rates. The highest concentration of CNPs reduced the total cell number and ratio of ICM: TE cells in parthenogenetic embryos, suggesting that there is a threshold where benefits are lost if exceeded. In cloned embryos, the CNPs25 group, as compared to all other treated groups, showed significantly higher maturation and cleavage rates. Furthermore, the blastocyst development rate in the CNPs25-treated group was significantly higher than that in the CNPs50-treated group, as was the total cell number. Moreover, we found that cloned embryos derived from the CNPs25-treated group showed significantly higher expression levels of Pou5f1, Dppa2, and Ndp52il genes, compared with those of the control and other treated groups. Our results demonstrated that 25 µg/ml CNPs treatment during IVM improves the developmental competence of porcine oocytes by reducing oxidative stress.     

Survivability and developmental competences of domestic cat (Felis catus) oocytes after Cryotech method vitrification

The aim of this study was to evaluate the applicability of the Cryotech technique for the vitrification of domestic cat (Felis catus) oocytes, as a model for other feline species threatened with extinction. This technique, in which oocytes are stored in a minimal volume of medium, is already widely used in human assisted reproductive technology. In the first part of this study, a viability test (EtBr/FDA) was used to evaluate the toxicity of the vitrification media (solutions). After IVM, oocytes were placed in vitrification and warming solutions according to the manufacturer's procedure, with or without exposure to liquid nitrogen. The solutions and the vitrification procedure each caused a reduction in oocyte viability, with survival rates of 71.4% in oocytes exposed to the Cryotech media (without cooling in liquid nitrogen), and 62% in oocytes that were vitrified. In the second part of the experiment, parthenogenetic activation was used to evaluate the developmental potential of oocytes previously vitrified using the Cryotech method. After warming, the oocytes were activated using a combination of 0.7 µM ionomycin in TCM 199 medium (5 min) followed by 2 mM 6-DMAP in TCM 199 supplemented with 10% FBS (3 hr), then cultured and evaluated every 24 hr for parthenogenetic cleavage. In the experimental group, 23/50 (46%) cleaved embryos were obtained. Domestic cat oocytes, vitrified by the Cryotech method, are characterized by high survival rates. However, it is necessary to improve the technique to increase the developmental competence of embryos obtained from vitrified oocytes.     

The effect of resveratrol on the developmental competence of porcine oocytes vitrified at germinal vesicle stage

We tested the effects of resveratrol both as a pre‐treatment and as a recovery treatment after warming during in vitro maturation (IVM) on the viability and developmental competence of porcine oocytes vitrified at the germinal vesicle stage. Pre‐treatment before vitrification of oocytes for 3 hr with 2 μM resveratrol did not affect survival, oocyte maturation and embryo developmental competence to the blastocyst stage after parthenogenetic activation. However, supplementation of the medium with resveratrol during subsequent IVM after vitrification and warming significantly improved the ability of surviving oocytes to develop to the blastocyst stage, and this effect was observed only on vitrified, but not on non‐vitrified oocytes. The intracellular levels of glutathione and hydrogen peroxide in oocytes were not affected by vitrification and resveratrol treatment. Also, there was no significant difference in the occurrence of apoptosis measured by annexin V binding between vitrified and non‐vitrified oocytes, regardless of the resveratrol treatment. In conclusion, resveratrol did not prevent the cellular damages in immature porcine oocytes during vitrification; however, when added to the IVM medium, it specifically improved the developmental competence of vitrified oocytes. Further research will be necessary to clarify the mechanisms of action of resveratrol on the recovery of vitrified oocytes from vitrification‐related damages.