FOLLICULAR MORPHOGENESIS DURING PERINATAL DEVELOPMENT

围产期发育期间的卵泡形态发生

• 批准号: 6740919
• 负责人: SHYAMAL K. ROY
• 金额: $ 25.73万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6740919
• 关键词: epidermal growth factor; follicle stimulating hormone; growth factor receptors; hamsters; hormone regulation /control mechanism; immunofluorescence technique; newborn animals; oogenesis; polymerase chain reaction; receptor expression; transforming growth factors

The mechanisms regulating the onset of follicular morphogenesis remain unresolved, but the differentiation of granulosa cells from pluripotential somatic cells and their interaction with oocytes appears to be an essential early step. In contrast to rats and mice, ovaries of newborn Syrian hamsters contain oocytes in the 1st meiotic prophase, and undifferentiated somatic cells. Therefore, we have an ideal animal model for studying the mechanism involved in producing the first cohort of follicles. Preliminary studies have shown that: [1] immunoinactivation of endogenous FSH results in nearly complete inhibition of primordial follicle formation and this can be reversed by equine chorionic gonadotropin (eCG), a hormone with FSH activity unaffected by the highly specific anti-FSH serum; [2] the failure of follicular formation is correlated with an appreciable reduction in the transcription and translation of the epidermal growth factor (EGF) receptor gene consistent with our earlier findings that FSH functions via EGF and its receptor; [3] exposure of neonatal ovaries in vivo or in vitro to eCG upregulates the expression of EGF, EGF-receptor and TGF-beta receptor associated with accelerated granulosa cell and follicle differentiation and [4] increased expression of FSH-receptor mRNA correlates with increased FSH function. We hypothesize that FSH controls the differentiation of pluripotential somatic cells into granulosa cells during the first phases of follicular morphogenesis by mechanisms that involve the spatio-temporal interaction of EGF and TGF-beta receptors with their appropriate ligands. This will be tested in vivo using anti-FSH antiserum and in vitro using fetal and early postnatal hamster ovaries exposed to FSH and/or growth factors. Measured parameters include [1] morphometric quantitation of follicle formation; [2] quantitative evaluation by Western immunoblotting, of the significance of EGF and TGF-beta ligand and receptor expression during granulosa cell differentiation; their cell- specific subtle expression will be identified by immunofluorescence; [3] correlation of changes in EGF and TGF-beta receptor mRNA, determined by RT-PCR quantitation, with gonadotropin-regulated differentiation and [4] measurement of ovarian steroidogenic activity to determine the functional significance of follicular development following in vitro hormone and/or growth factor manipulation. Results will contribute substantially to our understanding of the mechanisms involved in the initial steps of folliculogenesis, i.e., the formation of primordial follicles, which will prove valuable for improving the treatment and management of human infertility.

调节卵泡形态发生发作的机制尚未解决，但是颗粒细胞与多能体细胞的分化及其与卵母细胞的相互作用似乎是必不可少的早期步骤。与大鼠和小鼠相反，新生儿叙利亚仓鼠的卵巢中含有卵母细胞在第一级减数分裂预言和未分化的体细胞中。因此，我们有一个理想的动物模型，用于研究产生第一群卵泡队的机制。初步研究表明：[1]内源性FSH的免疫激活导致几乎完全抑制原始卵泡形成，并且可以通过马绒毛膜促性腺激素（ECG）（ECG）反转，这是一种具有FSH活性的激素，而FSH活性不受高度特异性的抗FSH ERANTE-FSH ERATIM的影响； [2]卵泡形成的失败与表皮生长因子（EGF）受体基因的转录和翻译的明显降低相关，这与我们较早的发现FSH通过EGF及其受体功能相关。 [3]在体内或体外暴露于ECG的接触EGF，EGF受体受体和TGF-β受体的表达与与FSH受体mRNA依靠FSH函数增加的表达相关的EGF，EGF受体和TGF-β受体的表达增加。我们假设FSH通过涉及EGF和TGF-Beta受体与合适的配体的机制来控制卵泡形态发生的第一阶段，在卵泡形态发生的第一阶段中控制多能体细胞向颗粒细胞的分化。这将使用抗FSH抗血清和体外使用胎儿和早期的产后仓鼠卵巢在体内进行测试，并在体外测试，暴露于FSH和/或生长因子。测得的参数包括[1]卵泡形成的形态定量； [2]通过西方免疫印迹的定量评估，对颗粒细胞分化过程中EGF和TGF-β配体的重要性以及受体表达的重要性；它们的细胞特异性微妙表达将通过免疫荧光鉴定。 [3]通过RT-PCR定量确定的EGF和TGF-β受体mRNA的变化与促性腺激素调节的分化以及[4]测量卵巢类固醇激素活性，以确定卵泡型在体外激素和/或生长因子操纵后的卵泡发育的功能显着性。结果将有助于我们对卵泡发生初始步骤的机制的理解，即原始卵泡的形成，这将证明对改善人类不育的治疗和管理非常有价值。