Senbon Shoichiro, Hirao Yuji, Miyano Takashi
Graduate School of Science and Technology, Faculty of Agriculture, Kobe University, Kobe 657-8501, Japan.
J Reprod Dev. 2003 Aug;49(4):259-69. doi: 10.1262/jrd.49.259.
Mammalian oogenesis occurs concomitantly with folliculogenesis in a coordinated manner in the ovaries. In vitro growth (IVG) culture systems of the oocytes have been developed as a new technology for utilizing incompetent oocytes in the ovary as a source of mature oocytes as well as for studying oogenesis, folliculogenesis, and oocyte-somatic cell interactions. The results of IVG experiments have suggested that direct association of oocytes and surrounding granulosa cells supports oocyte viability and growth through the gap junctions, which are efficient conduits for low molecular weight substances. It has been revealed that granulosa cells metabolize some molecules which are in turn transported into the oocytes. IVG systems have also provided evidence that FSH promotes the development of follicles at secondary or later stages by its stimulation of proliferation and differentiation of granulosa cells, and perhaps by its anti-apoptotic effects. In addition, interactions between granulosa cell-derived KIT ligands and oocyte KIT receptors have been suggested as initiating oocyte growth and follicular development. Furthermore, recent findings suggest there are growth factors derived from oocytes such as GDF-9 and BMP-15. With such factors, oocytes participate in follicular development by regulating the differentiation of surrounding somatic cells. These bidirectional communications between oocytes and somatic cells are important for oocyte growth and follicular development. IVG systems should provide further information regarding oogenesis and folliculogenesis in the ovary.
哺乳动物的卵子发生与卵泡发生在卵巢中以协调的方式同时进行。卵母细胞的体外生长(IVG)培养系统已被开发为一种新技术,用于将卵巢中无功能的卵母细胞作为成熟卵母细胞的来源加以利用,同时也用于研究卵子发生、卵泡发生以及卵母细胞与体细胞的相互作用。IVG实验结果表明,卵母细胞与周围颗粒细胞的直接关联通过缝隙连接支持卵母细胞的存活和生长,缝隙连接是低分子量物质的有效通道。现已发现,颗粒细胞代谢某些分子,这些分子进而被转运到卵母细胞中。IVG系统还提供了证据,表明促卵泡激素(FSH)通过刺激颗粒细胞的增殖和分化,或许还通过其抗凋亡作用,促进次级或更后期卵泡的发育。此外,颗粒细胞衍生的KIT配体与卵母细胞KIT受体之间的相互作用被认为启动了卵母细胞的生长和卵泡发育。此外,最近的研究结果表明,存在源自卵母细胞的生长因子,如生长分化因子9(GDF-9)和骨形态发生蛋白15(BMP-15)。借助这些因子,卵母细胞通过调节周围体细胞的分化参与卵泡发育。卵母细胞与体细胞之间的这些双向通讯对卵母细胞生长和卵泡发育至关重要。IVG系统应能提供有关卵巢中卵子发生和卵泡发生的更多信息。