Guigon Céline J, Mazaud Séverine, Forest Maguelone G, Brailly-Tabard Sylvie, Coudouel Noëlline, Magre Solange
Laboratoire de Physiologie et Physiopathologie, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7079, Université Pierre et Marie Curie,75005 Paris, France.
Endocrinology. 2003 Aug;144(8):3651-62. doi: 10.1210/en.2003-0072.
In rats, the pool of primordial follicles is established within the first 3 d postnatally (dpn). Immediately after their differentiation, a subset of follicles begins to grow and constitutes the initial follicular waves. In this study we investigated the development of these early growing follicles after deletion of the primordial follicle pool induced by 1.5 Gy gamma-irradiation at 5 dpn. Within only 24 h, i.e. at 6 dpn, 99% of the primordial follicles disappeared, whereas most of the growing follicles remained unaffected. The study of these surviving follicles throughout the immature period has shown that their subsequent growth proceeded normally, as assessed by proliferating cell nuclear antigen immunostaining and follicular counts. No modification in the process of follicular atresia, studied by terminal deoxynucleotidyltransferase-mediated deoxy-UTP-fluorescein nick end labeling and Southern blot of DNA fragmentation analysis, was observed. Complementary analysis, by either in situ hybridization for inhibin subunits, P450 aromatase, and LH receptor mRNAs or plasma dosages of 17beta-estradiol and inhibin B, further showed that follicular maturation was unaltered. In line with these observations, pubertal onset was normal, regarding both age and ovulation rate. Nevertheless, as a consequence of the nonrenewal of the growing pool, the follicular complement was practically exhausted at puberty, and 90% of the females evidenced sterility by 4 months. Altogether, our results demonstrate that the deletion of the primordial follicle pool has induced no modification in the growth pattern of the early growing follicles that develop as their counterparts in control ovaries. Within the immature period, the initial follicular waves ensure the ovarian functionality and thus play a key role in the initiation of reproductive life.
在大鼠中，原始卵泡池在出生后最初3天内形成。卵泡分化后，一部分卵泡开始生长并构成初始卵泡波。在本研究中，我们调查了在出生后5天经1.5 Gy γ射线照射诱导原始卵泡池缺失后，这些早期生长卵泡的发育情况。仅在24小时内，即出生后6天，99%的原始卵泡消失，而大多数生长卵泡未受影响。对这些存活卵泡在整个未成熟期的研究表明，通过增殖细胞核抗原免疫染色和卵泡计数评估，它们随后的生长正常进行。通过末端脱氧核苷酸转移酶介导的脱氧UTP-荧光素缺口末端标记和DNA片段分析的Southern印迹法研究卵泡闭锁过程，未观察到任何改变。通过对抑制素亚基、P450芳香化酶和LH受体mRNA进行原位杂交或对17β-雌二醇和抑制素B进行血浆定量的补充分析进一步表明，卵泡成熟未受影响。与这些观察结果一致，青春期开始在年龄和排卵率方面均正常。然而，由于生长卵泡池无法更新，卵泡储备在青春期时几乎耗尽，90%的雌性在4个月时出现不育。总之，我们的结果表明，原始卵泡池的缺失并未导致早期生长卵泡的生长模式发生改变，这些卵泡的发育与对照卵巢中的卵泡相同。在未成熟期内，初始卵泡波确保了卵巢功能，因此在生殖生活开始中起关键作用。
