Evidence of Melatonin Synthesis in the Cumulus Oocyte Complexes and its Role in Enhancing Oocyte Maturation In Vitro in Cattle
Evidence of Melatonin Synthesis in the Cumulus Oocyte Complexes and its Role in Enhancing Oocyte Maturation In Vitro in Cattle
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DOI：
10.1002/mrd.21295
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发表时间：
2011-04-01
影响因子：
2.5
通讯作者：
Nagai, Takashi
中科院分区：
文献类型：
--
作者：
El-Raey, Mohamed;Geshi, Masaya;Nagai, Takashi
褪黑激素是一种多功能分子，介导几种昼夜节律和季节性生殖过程。然而，褪黑激素在调节生殖中的确切作用还不完全清楚，特别是它对卵泡和卵母细胞的作用。本研究旨在探讨褪黑素受体MTNR 1A和MTNR 1B基因在牛卵母细胞及其卵丘细胞中的表达，以及褪黑素对牛卵母细胞核质成熟的影响。采用添加0、10、50和100 ng/ml褪黑激素的TCM-199培养屠宰场卵巢卵丘-卵母细胞复合体（COCs）。RT-PCR检测ASMT、MTNR 1A和MTNR 1B基因的表达。此外，还研究了褪黑素对卵丘细胞增殖、核成熟、线粒体特征和COCs类固醇合成的影响。此外，活性氧（ROS）的水平进行了评估，在裸露的卵母细胞。我们的研究表明，ASMT和MTNR 1A基因在COCs中表达，而MTNR 1B基因仅在卵母细胞中表达。此外，在体外成熟培养液中添加10和50 ng/ml褪黑激素可显著增强卵母细胞核成熟、卵丘细胞扩增并改变线粒体分布模式，但对卵母细胞线粒体活性和COCs类固醇生成无影响。褪黑激素处理的卵母细胞有一个显着低于对照组的活性氧水平。COCs中褪黑素受体的存在及其对卵母细胞核和胞质事件的促进作用，表明这种激素在调节牛卵母细胞成熟中的潜在重要作用。此外，COCs中ASMT转录本的存在表明这些细胞可能参与褪黑激素的生物合成。摩尔Reprod. Dev. 78：250-262，2011. (C)2011 Wiley-Liss，Inc.
Melatonin is a multifunctional molecule that mediates several circadian and seasonal reproductive processes. The exact role of melatonin in modulating reproduction, however, is not fully understood-especially its effects on the ovarian follicles and oocytes. This study was conducted to investigate the expressions of the ASMT and melatonin-receptor MTNR1A and MTNR1B genes in bovine oocytes and their cumulus cells, as well as the effects of melatonin on oocyte nuclear and cytoplasmic maturation in vitro. Cumulus-oocyte complexes (COCs) from abattoir ovaries were cultured in TCM-199 supplemented with melatonin at concentrations of 0, 10, 50, and 100 ng/ml. The expression of ASMT, MTNR1A, and MTNR1B genes was evaluated by RT-PCR. Moreover, the effects of melatonin on cumulus cell expansion, nuclear maturation, mitochondrial characteristics and COCs steroidogenesis were investigated. Furthermore, the level of reactive oxygen species (ROS) was evaluated in denuded oocytes. Our study revealed that ASMT and MTNR1A genes were expressed in COCs, while the MTNR1B gene was expressed only in oocytes. Additionally, melatonin supplementation at 10 and 50 ng/ml to in vitro maturation medium significantly enhanced oocyte nuclear maturation, cumulus cell expansion and altered the mitochondrial distribution patterns, but had no effects on oocyte mitochondrial activity and COCs steroidogenesis. Melatonin-treated oocytes had a significantly lower level of ROS than controls. The presence of melatonin receptors in COCs and its promoting effects on oocyte nuclear and cytoplasmic events, indicate the potentially important roles of this hormone in regulating bovine oocyte maturation. Moreover, the presence of ASMT transcript in COCs suggests the possible involvement of these cells in melatonin biosynthesis. Mol. Reprod. Dev. 78: 250-262, 2011. (C) 2011 Wiley-Liss, Inc.