THE ROLE OF COMMUNICATIONS AMONG THE OVARIAN CELLS IN EARLY STAGE OF THE FOLLICULAR DEVELOPMENT AND ATRESIA

我们研究了在卵泡发育早期，颗粒细胞（GC）、卵泡细胞（TC）和卵母细胞之间的细胞通讯在卵泡成熟和闭锁中的作用。在研究的第一部分，我们研究了TC对GC分化和类固醇产生的影响。TC增强了GC中芳香化酶mRNA的表达，导致雌二醇的产生增加。TC未改变GC中P450scc、3β-HSD、LHr和StAR的孕酮生成和mRNA表达。结果表明，TC参与了雌激素产生的两个限速步骤；即雄激素底物的产生和芳香化酶的调节，以及tc衍生的因子以一种反映类固醇生成的方式调节雌二醇和黄体酮的产生。在本研究的第二部分，我们检验了基质细胞（SC）在早期卵泡发育过程中分化为TC的假设，并且这一过程涉及与GC的相互作用。GC增加了SC中脂滴和线粒体的数量，刺激了SC中雄烯二酮的产生和LH受体mRNA的表达，提示GC参与了基质细胞LH反应性的功能分化和获得。在最后的研究中，卵母细胞衍生的生长分化因子-9 （GDF-9）如何控制颗粒和卵泡细胞的功能。我们发现GDF-9通过激活GC中PI3K/Akt通路和FSH受体mRNA表达来保护颗粒细胞免于凋亡。

We have studied the role of cellular communication among the granulosa cell (GC) theca cell (TC) and oocyte in follicular maturation and atresia during the early stage of the development.In the first part of the study, we investigated the effects of TC on GC differentiation and steroid production. TC enhanced aromatase mRNA expression in GC resulting in an increase in estradiol production. TC did not alter progesterone production and mRNA expression in GC for P450scc, 3β-HSD, LHr, and StAR. The results indicate that TC are involved in both rate-limiting steps in estrogen production; i.e., androgen substrate production and aromatase regulation, and that TC-derived factors regulate estradiol and progesterone production in a way that reflects steroidogenesis.In the second part of the study, we have examined the hypothesis that stromal cells (SC) differentiate into TC during early follicular development and that this process involves the interaction with GC. GC increased the number of lipid droplets and mitochondria, and stimulated androstenedione production and LH receptor mRNA expression in SC, suggested that GC are involved in the functional differentiation of and acquisition of LH responsiveness in stromal cells.In the last study, how oocyte-derived growth differentiation factor-9 (GDF-9) controls granulose and theca cell function. We found that GDF-9 protects granulosa cells from undergoing apoptosis via activation of the PI3K/Akt pathway and FSH receptor mRNA expression in GC.