Nogueira D, Cortvrindt R, De Matos D G, Vanhoutte L, Smitz J
Follicle Biology Laboratory, Vrije Universiteit Brussel, Brussels, 1090 Belgium.
Biol Reprod. 2003 Dec;69(6):2045-52. doi: 10.1095/biolreprod.103.021105. Epub 2003 Aug 20.
In vitro use of arresters of meiosis could improve cytoplasmic maturation of immature oocytes by controlling the period of prophase I. Phosphodiesterases (PDE) are responsible for the breakdown and concomitant inactivation of the cyclic nucleotides cAMP and cGMP and are implicated in the regulation of oocyte meiotic maturation. Selective inhibitors of phosphodiesterase type 3 (PDE3) prevent meiotic resumption of mammalian oocytes. This study evaluated the impact of meiosis arrest by PDE3 inhibitor, Org 9935, on developmental competence of geminal vesicle (GV)-stage oocytes from small antral follicles. Cumulus-oocyte complexes (COC), retrieved from antral follicles 24 h after eCG exposure and cultured in the presence of PDE3 inhibitor (10 microM) for an additional 24 h, remained arrested in the meiotic prophase. The GV configuration of oocytes before and after the arrest by PDE3 inhibitor was examined. After the period of meiosis arrest, a significantly increased proportion of oocytes had acquired a nucleolus surrounded by a condensed chromatin rim at the GV, which is a morphological correlate of transcriptional repression. Removal of inhibitor resulted in 90.6% +/- 8.3% of oocytes with the first polar body extruded. Fertilization was significantly improved in oocytes that had been arrested compared with oocytes collected 24 h after eCG and undergoing in vitro maturation immediately. Embryonic preimplantation and live offspring rates of arrested oocytes were higher, although not significantly, than those of nonarrested oocytes. These results suggest that a temporal block of meiosis by PDE3 inhibitor promotes developmental competence of mice oocytes retrieved from small antral follicles.
在体外使用减数分裂阻滞剂可通过控制减数第一次分裂前期的时长来改善未成熟卵母细胞的细胞质成熟。磷酸二酯酶（PDE）负责环磷酸腺苷（cAMP）和环磷酸鸟苷（cGMP）的分解及随之而来的失活，并参与卵母细胞减数分裂成熟的调节。3型磷酸二酯酶（PDE3）的选择性抑制剂可阻止哺乳动物卵母细胞的减数分裂恢复。本研究评估了PDE3抑制剂Org 9935对小窦状卵泡中生殖泡（GV）期卵母细胞发育能力的减数分裂阻滞影响。从注射eCG后24小时的窦状卵泡中获取卵丘-卵母细胞复合体（COC），并在PDE3抑制剂（10微摩尔）存在的情况下再培养24小时，这些复合体仍停滞在减数分裂前期。检查了PDE3抑制剂阻滞前后卵母细胞的GV形态。在减数分裂阻滞期后，有显著比例增加的卵母细胞在GV处获得了被浓缩染色质边缘包围的核仁，这是转录抑制的形态学相关特征。去除抑制剂后，90.6%±8.3%的卵母细胞排出了第一极体。与eCG注射后24小时收集并立即进行体外成熟的卵母细胞相比，经过阻滞的卵母细胞受精情况有显著改善。尽管未达到显著水平，但阻滞卵母细胞的胚胎植入前和活产率高于未阻滞的卵母细胞。这些结果表明，PDE3抑制剂对减数分裂的暂时阻滞可促进从小窦状卵泡中获取的小鼠卵母细胞的发育能力。
