Hutt Karla J, McLaughlin Eileen A, Holland Michael K
Pest Animal Control Cooperative Research Centre, CSIRO Sustainable Ecosystems, G.P.O. Box 284, Canberra, ACT 2615, Australia.
Cell Tissue Res. 2006 Dec;326(3):809-22. doi: 10.1007/s00441-006-0223-3. Epub 2006 Jul 8.
Of all the stages of mammalian folliculogenesis, the primordial to primary follicle transition is the least understood. In order to gain new insights into this process, we have conducted a comprehensive morphological, morphometric and molecular study of ovarian organisation and early follicle development in the rabbit. The structure of ovaries collected from rabbits aged from 2-12 weeks (a period encompassing primordial follicle formation, activation and the first wave of folliculogenesis in this species) has been analysed by light microscopy and the follicles present have been measured and scored for their developmental stage. To establish useful molecular markers of activation, we have further classified follicles according to their expression of the proliferative marker, proliferating cell nuclear antigen, and the zona pellucida protein, ZPB. The activation of primordial follicles is initiated immediately following their formation in the rabbit ovary and is characterised by oocyte growth, granulosa cell morphogenesis and increased granulosa cell mitosis. Enhanced ZPB protein expression at the oolemma is also associated with follicle activation and development. Few primordial follicles in the juvenile rabbit ovary are lost by atresia, as assessed by the TUNEL assay. The appearance of apoptotic granulosa cells is however coincident with the development of antral follicles. This study thus describes the temporal and spatial regulation of early follicular development in the post-natal rabbit ovary and, for the first time, shows that the primordial to primary transition in the juvenile rabbit is a highly ordered process occurring within quantifiable parameters.
在哺乳动物卵泡发生的所有阶段中，原始卵泡向初级卵泡的转变是了解最少的。为了对这一过程有新的认识，我们对兔卵巢组织和早期卵泡发育进行了全面的形态学、形态计量学和分子研究。通过光学显微镜分析了从2至12周龄兔（涵盖该物种原始卵泡形成、激活和卵泡发生第一波的时期）收集的卵巢结构，并对存在的卵泡进行了测量，并根据其发育阶段进行评分。为了建立有用的激活分子标记，我们根据增殖标记物增殖细胞核抗原和透明带蛋白ZPB的表达对卵泡进行了进一步分类。原始卵泡在兔卵巢中形成后立即开始激活，其特征是卵母细胞生长、颗粒细胞形态发生和颗粒细胞有丝分裂增加。卵膜处ZPB蛋白表达增强也与卵泡激活和发育有关。通过TUNEL检测评估，幼年兔卵巢中很少有原始卵泡因闭锁而丢失。然而，凋亡颗粒细胞的出现与窦状卵泡的发育同时发生。因此，本研究描述了产后兔卵巢早期卵泡发育的时空调节，并首次表明幼年兔从原始卵泡到初级卵泡的转变是一个在可量化参数内发生的高度有序的过程。
