Semaphorin 6c在颗粒细胞与卵母细胞非同步发育导致卵泡闭锁中的作用及机制研究

As the ovarian follicle is atresia gradually and the follicle pool is exhausted eventually, women come to menopause. High level of FSH during the perimenopausal period promotes the inappropriate differentiation of the granulosa cells of some follicles, which results in the asynchronous maturation of the granulosa cells and oocyte. These follicles eventually become atretic. We have found the expression level of new gene semaphorin 6c in the ovary was reduced as the mice growing older. The atretic follicles were increased significantly when sema6c was down-regulated in the ovary in vivo.The diameter of follicles cultured was restrained with sema6c down-regulated in vitro. And the function of oocyte was decreased but the granulosa cells were inappropriate maturation, displaying the characteristic of the asynchronous maturation of the granulosa cells and oocyte.Now we don't know whether the asynchronous maturation of granulosa cells and oocytes will make the follicle atretic and what the mechanism is. We are planning to up/down-regulate the expression of sema6c in the oocyte and granulosa cell in vitro and in the ovrain tissue in vivo to study the role of asynchronous maturation of the granulosa cells and oocyte in the process of follicular atresia. Then the regulation among sema6c and GDF-9 and FSH/cAMP/PKA signal pathway will be researched. We want to know more about the molecular function of sema6c and the mechanism of asynchronous maturation of granulosa cells and oocyte during the process of follicle atresia.

女性绝经是由于卵泡不断闭锁、最终卵泡池被耗竭。在近围绝经期，FSH增高使部分卵泡的颗粒细胞过早分化成熟，导致与卵母细胞发育不同步引起卵泡闭锁。我们前期研究发现新基因Semaphorin 6c（简称Sema6c）在小鼠卵巢中的表达水平随周龄增长而降低；体内下调表达后卵泡闭锁显著增加；体外实验下调表达后卵泡生长受抑，卵母细胞功能下降、颗粒细胞却异常分化成熟，即颗粒细胞与卵母细胞非同步发育的特征。这一细胞非同步发育是否引起卵泡闭锁及其具体机制尚不清楚。基于此，我们拟通过小鼠体内实验从卵巢组织整体水平、并通过体外实验分别从卵母细胞、颗粒细胞水平上调/下调Sema6c表达，研究Sema6c在卵母、颗粒细胞非同步发育导致卵泡闭锁这一过程中的作用,及其与GDF-9、FSH/cAMP/PKA信号通路的调控关系；以期更深认识Sema6c的分子功能及其在颗粒细胞、卵母细胞非同步发育导致卵泡闭锁的内在机制。

女性绝经是由于卵泡不断闭锁、最终卵泡池被耗竭。在近围绝经期， FSH 增高使部分卵泡的颗粒细胞过早分化成熟，导致与卵母细胞发育不同步引起卵泡闭锁。 我们前期研究发现新基因 Semaphorin 6c （简称 Sema6c） 在小鼠卵巢中的表达水平随周龄增长而降低；体内下调表达后卵泡闭锁显著增加； 体外实验下调表达后卵泡生长受抑，卵母细胞功能下降、颗粒细胞却异常分化成熟， 即颗粒细胞与卵母细胞非同步发育的特征。 这一细胞非同步发育是否引起卵泡闭锁及其具体机制尚不清楚。基于此， 我们通过小鼠体内实验从卵巢组织整体水平、并通过体外实验分别从卵泡、颗粒胞水平上调/下调 Sema6c 表达，研究 Sema6c在卵母、颗粒细胞非同步发育导致卵泡闭锁这一过程中的作用。小鼠体内实验下调卵巢组织sema6c表达，致闭锁卵泡增加，始基卵泡数目减少。卵泡体外培养体系中，下调sema6c表达导致卵泡发育过程中颗粒细胞过度分化，抑制卵泡的生长并促进其颗粒细胞的凋亡而导致卵泡闭锁。颗粒细胞体外培养发现低表达sema6c促进颗粒细胞的分化，激素合成增加，western blot验证其机制为sema6c与cAMP及PI3K-AKT通路相互作用而引起颗粒细胞的凋亡及分化过程。