Thomas Fiona H, Ethier Jean-François, Shimasaki Shunichi, Vanderhyden Barbara C
Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa Regional Cancer Centre, Ottawa, Ontario, Canada K1H 1C4.
Endocrinology. 2005 Feb;146(2):941-9. doi: 10.1210/en.2004-0826. Epub 2004 Nov 11.
Oocyte-granulosa cell communication is essential for oocyte development. The aims of this study were: 1) to determine the effect of FSH on expression of Kit ligand (KL), growth/differentiation factor-9, bone morphogenetic protein (BMP)-15, and Kit during growth of oocyte-granulosa cell complexes (OGCs) in vitro; 2) to investigate the role of BMP-15 in regulation of KL expression; and 3) to correlate mRNA expression with oocyte growth. OGCs from 12-d-old mice were cultured for up to 7 d in the presence of FSH [0.05 ng/ml (low), 5 ng/ml (high)] or BMP-15 (10 or 100 ng/ml). Transcripts were quantified using real-time RT-PCR, and oocyte and OGC diameters were measured. FSH regulated KL expression in a biphasic manner, with low FSH decreasing the KL-1/KL-2 ratio, and high FSH increasing the KL-1/KL-2 ratio, compared with controls (P < 0.05). The decrease in KL-1/KL-2 ratio with low FSH was due to increased KL-2 mRNA expression. Both FSH concentrations increased OGC diameter (P < 0.05), but only low FSH promoted oocyte growth (P < 0.05). High FSH also decreased BMP-15 expression (P < 0.05). FSH-stimulated oocyte growth was inhibited by Gleevec, an inhibitor of Kit activity. BMP-15 increased both KL-1 and KL-2 mRNA levels in a dose-dependent manner (P < 0.05) but did not alter the KL-1/KL-2 ratio or promote oocyte growth. When the KL-1/KL-2 ratio was increased by exogenous KL-1, FSH-stimulated oocyte growth was suppressed (P < 0.05), suggesting that lowered KL-1/KL-2 ratio is important for oocyte growth. In summary, the correct concentration of FSH is crucial for appropriate modulation of KL and BMP-15 to promote oocyte growth.
卵母细胞-颗粒细胞间的通讯对于卵母细胞发育至关重要。本研究的目的是：1）确定促卵泡激素（FSH）对体外培养的卵母细胞-颗粒细胞复合体（OGC）生长过程中Kit配体（KL）、生长/分化因子-9、骨形态发生蛋白（BMP）-15和Kit表达的影响；2）研究BMP-15在调节KL表达中的作用；3）将mRNA表达与卵母细胞生长相关联。从12日龄小鼠获取的OGC在存在FSH[0.05 ng/ml（低剂量）、5 ng/ml（高剂量）]或BMP-15（10或100 ng/ml）的情况下培养长达7天。使用实时逆转录聚合酶链反应（RT-PCR）对转录本进行定量，并测量卵母细胞和OGC的直径。FSH以双相方式调节KL表达，与对照组相比，低剂量FSH降低KL-1/KL-2比值，高剂量FSH增加KL-1/KL-2比值（P<0.05）。低剂量FSH导致KL-1/KL-2比值降低是由于KL-2 mRNA表达增加。两种FSH浓度均增加了OGC直径（P<0.05），但只有低剂量FSH促进了卵母细胞生长（P<0.05）。高剂量FSH也降低了BMP-15表达（P<0.05）。Kit活性抑制剂格列卫抑制了FSH刺激的卵母细胞生长。BMP-15以剂量依赖方式增加KL-1和KL-2 mRNA水平（P<0.05），但未改变KL-1/KL-2比值或促进卵母细胞生长。当外源性KL-1增加KL-1/KL-2比值时，FSH刺激的卵母细胞生长受到抑制（P<0.05），表明降低的KL-1/KL-2比值对卵母细胞生长很重要。总之，正确浓度的FSH对于适当调节KL和BMP-15以促进卵母细胞生长至关重要。
