Altered cytoplasmic maturation in rescued in vitro matured oocytes
Altered cytoplasmic maturation in rescued in vitro matured oocytes
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DOI：
10.1093/humrep/dez052
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发表时间：
2019-06-01
影响因子：
6.1
通讯作者：
Vassena, R.
中科院分区：
文献类型：
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作者：
Ferrer-Vaquer, A.;Barragan, M.;Vassena, R.
研究问题：培养条件是否影响裸露未成熟非GV卵母细胞的胞质成熟？总结回答：裸露的非GV卵母细胞的成熟率不受培养基的影响，但与体内成熟相比，体外成熟似乎改变了线粒体膜电位，内质网（ER）和肌动蛋白细胞骨架。裸露的未成熟非GV卵母细胞的体外成熟有益于体内MII卵母细胞收集较差的周期，但非GV卵母细胞的成熟水平仅通过极体挤出来评分。由于卵母细胞成熟包括核和细胞质成熟以获得完整的减数分裂能力，因此需要进一步了解体外培养中细胞质成熟的情况。研究设计、规模、持续时间：本基础研究于2017年1月至2018年9月进行。将339个剥脱的未成熟非GV期卵母细胞在SAGE 1-Step（177）或G-2 PLUS（162）中培养6-8 h，并将72个体内成熟的MII期卵母细胞用作对照。对培养的未成熟非GV卵母细胞的极体挤出进行评分，并分析线粒体膜电位（Delta Psi m）、ER簇、皮质颗粒数量和分布、纺锤体形态和肌动蛋白细胞骨架组织。所获得的参数值进行了比较，在体内成熟的MII卵母细胞的参数values.Main结果和机会的作用：在G-2 PLUS和SAGE 1-Step培养的卵母细胞的成熟率是相似的（65%vs 64.2%; P = 0.91）。观察到的皮质颗粒密度差异无统计学意义。体外和体内成熟的MII期卵母细胞的纺锤体形态学参数基本相似。然而，ER簇的数量，Δ Psim和皮质肌动蛋白厚度显示出显着差异，在体内MII卵母细胞和裸露的未成熟的非GV卵母细胞在体外培养，直到减数分裂完成。由于技术限制（固定方法和荧光染料重叠），每个卵母细胞只能研究一个或两个参数。因此，一个全球性的观点，为每个人的成熟状态，不能获得。更广泛的影响的调查结果：表征在体外成熟的卵母细胞在细胞水平上将有助于我们了解的差异，观察到的临床结果与救援IVM相比，在体内MII卵母细胞，并提高适用的培养方法。
STUDY QUESTION: Do culture conditions affect cytoplasmic maturation in denuded immature non-GV oocytes?SUMMARY ANSWER: The maturation rate of denuded non-GV oocytes is not affected by culture media, but in vitro maturation seems to alter the mitochondrial membrane potential, endoplasmic reticulum (ER) and actin cytoskeleton compared with in vivo maturation.WHAT IS KNOWN ALREADY: In vitro maturation of denuded immature non-GV oocytes benefits cycles with poor in vivo MII oocyte collection, but maturation levels of non-GV oocytes are only scored by polar body extrusion. Since oocyte maturation involves nuclear as well as cytoplasmic maturation for full meiotic competence, further knowledge is needed about cytoplasmic maturation in in vitro culture.STUDY DESIGN, SIZE, DURATION: This basic research study was carried out between January 2017 and September 2018.PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 339 denuded immature non-GV oocytes were cultured in SAGE 1-Step (177) or G-2 PLUS (162) for 6-8 h after retrieval, and 72 in vivo matured MII oocytes were used as controls. Cultured immature non-GV oocytes were scored for polar body extrusion and analysed for mitochondrial membrane potential (Delta Psi m), ER clusters, cortical granules number and distribution, spindle morphology and actin cytoskeleton organization. The obtained parameter values were compared to in vivo matured MII oocyte parameter values.MAIN RESULTS AND THE ROLE OF CHANCE: The maturation rates of oocytes cultured in G-2 PLUS and SAGE 1-Step were similar (65% vs 64.2%; P = 0.91). The differences observed in cortical granule density were not statistically significant. Also spindle morphometric parameters were mostly similar between in vitro and in vivo matured MII oocytes. However, the number of ER clusters, the Delta Psi m and the cortical actin thickness showed significant differences between in vivo MII oocytes and denuded immature non-GV oocytes cultured in vitro until meiosis completion.LIMITATIONS, REASONS FOR CAUTION: Frozen-thawed oocytes together with fresh oocytes were used as controls. Due to technical limitations (fixation method and fluorochrome overlap), only one or two parameters could be studied per oocyte. Thus, a global view of the maturation status for each individual oocyte could not be obtained.WIDER IMPLICATIONS OF THE FINDINGS: Characterization of in vitro matured oocytes at the cellular level will help us to understand the differences observed in the clinical outcomes reported with rescue IVM compared to in vivo MII oocytes and to improve the culture methods applied.