Nonowaki Shouko, Takahashi Katsuhiko, Horiuchi Toshitaka
Graduate School of Comprehensive Scientific Research Prefectural University of Hiroshima 727-0023 Hiroshima Japan.
Hiroshima HART Clinic 730-0051 Hiroshima Japan.
Reprod Med Biol. 2009 Dec 23;9(2):83-89. doi: 10.1007/s12522-009-0043-8. eCollection 2010 Jun.
The aim of this study is to determine the optimal culture period for meiotic maturation and developmental competence of in vitro-grown mouse oocytes.
Early preantral follicles with diameter of 100-130 μm were collected mechanically from day 14 mouse ovaries and cultured for 8, 10, and 12 days. The diameters of follicles and oocytes were measured, and chromatin configuration in oocytes was observed. We also examined meiotic maturation by human chorionic gonadotropin (hCG)/epidermal growth factor (EGF) stimulation, developmental competence of fertilized oocytes to blastocysts, and apoptosis in blastocysts.
The follicular diameter increased significantly from days 4 to 10, and the diameter of day 12 oocytes was significantly larger than day 8 or earlier oocytes. Chromatin configuration around the nucleolus was transformed from "nonsurrounded (immature)" to "surrounded (mature)" after 10 days. Furthermore, MII rate of day 10 and 12 oocytes was significantly higher than that of day 8 oocytes. The blastocyst rate of day 10 oocytes was higher than that of day 8 or 12 oocytes. The blastocyst apoptotic rate of day 12 oocytes was higher than that of day 10 oocytes.
Long culture periods of in vitro-grown oocytes affect meiotic maturation, developmental competence to blastocysts, and apoptosis.
本研究旨在确定体外培养的小鼠卵母细胞减数分裂成熟及发育能力的最佳培养时间。
从第14天的小鼠卵巢中机械收集直径为100 - 130μm的早期腔前卵泡，并培养8、10和12天。测量卵泡和卵母细胞的直径，观察卵母细胞中的染色质构型。我们还通过人绒毛膜促性腺激素（hCG）/表皮生长因子（EGF）刺激检测减数分裂成熟情况、受精卵发育至囊胚的能力以及囊胚中的细胞凋亡情况。
卵泡直径在第4天至第10天显著增加，第12天卵母细胞的直径显著大于第8天或更早的卵母细胞。10天后，核仁周围的染色质构型从“非环绕（未成熟）”转变为“环绕（成熟）”。此外，第10天和第12天卵母细胞的MII率显著高于第8天卵母细胞。第10天卵母细胞的囊胚率高于第8天或第12天卵母细胞。第12天卵母细胞的囊胚凋亡率高于第10天卵母细胞。
体外培养的卵母细胞培养时间过长会影响减数分裂成熟、发育至囊胚的能力以及细胞凋亡。
