QUANTITATIVE AND CYTOLOGICAL STUDY OF OOGONIA AND OOCYTES IN FOETAL AND NEONATAL RAT
QUANTITATIVE AND CYTOLOGICAL STUDY OF OOGONIA AND OOCYTES IN FOETAL AND NEONATAL RAT
复制标题
DOI：
10.1098/rspb.1962.0019
复制
发表时间：
1962-01-01
期刊：
影响因子：
--
通讯作者：
MANDL, AM
中科院分区：
文献类型：
--
作者：
BEAUMONT, HM;MANDL, AM
为了将卵原细胞和发育中的卵母细胞的形态学变化与其数量的波动联系起来，对胎儿和新生大鼠（产后14.5天至产后2天）的卵巢进行了研究。对西葫芦不同发育阶段的生殖细胞染色体构型进行了研究。设计了一种容量法，用于分别估计正常和退化生殖细胞的群体。对接种后19.5天的胚细胞和体细胞中的有丝分裂数进行了计数。卵原细胞在交配后17-5天内有丝分裂活跃。大多数卵母细胞减数分裂的细线期开始（交配后17.5至18.5天）。与正常卵原细胞分裂数量的急剧下降相吻合。偶线期的持续时间似乎短得多（19.5至20.5天p.c.）粗线期（20.5天）的平均值高于粗线期（20.5天）。至2天p. p.）。双线期的卵母细胞通常在产后2天出现。出生后第一天进入网状期或静息期的生殖细胞数量很少，但在第二天增加。观察到四种不同的生殖细胞变性“波”。第一种发生在减数分裂开始之前，影响少数卵原细胞，其特征为固缩。第二种以分裂卵原细胞的退化为特征，可能发生在有丝分裂前期或之前。这种“闭锁分裂”在交配后18.5天达到高峰，此时正常的有丝分裂频率相对较低。第三种影响生殖细胞进入减数分裂前期（特别是粗线期）后;染色体浓缩，细胞质变成嗜酸性粒细胞（称为“Z”细胞）。第四个影响双线期的生殖细胞。卵原细胞有丝分裂与生殖细胞数量的增加有关，从交配后第14.5天的12000增加到交配后第17.5天的71000。“闭锁分裂”的出现在很大程度上导致了17.5天至18.5天之间正常生殖细胞数量减少约3000个。另一方面，成功的有丝分裂使生殖细胞总数在同一时间间隔内增加了约4000个。从第18.5天开始，正常生殖细胞的总数和数量都稳步下降，首先是由于“闭锁分裂”的发生，然后是“Z”细胞和闭锁细胞在双线期的退化。因此，在出生后2天，正常生殖细胞的峰值数量（在交配后17.5天为64000）已经下降到19000，总人口（峰值75000在18.5天p.c.）减少到27000人。大多数生殖细胞似乎在变性开始后24小时内从卵巢中消除。
The ovaries of fetal and neonatal rats (14.5 days post coitum to 2 days post partum) have been studied in order to correlate morphological changes in oogonia and developing oocytes with fluctuations in their numbers. The chromosomal configurations of germ cells at different developmental stages were examined in squash preparations. A volumetric method was devised for the separate estimation of the populations of normal and degenerating germ cells. Counts were made of the numbers of mitoses in germinal and somatic cells up to 19.5 days p.c. Oogonia are mitotically active up to 17-5 days p.c. The onset of the leptotene phase of meiosis in the majority of oocytes (17.5 to 18.5 days p.c.) coincides with a sharp decline in the number of normal oogonial divisions. The duration of the zygotene phase appears to be considerably shorter (19.5 to 20.5 days p.c.) than that of pachytene (range 20.5 days p.c. to 2 days p.p.). Oocytes in the diplotene phase are typically seen at 2 days p.p. The number of germ cells attaining the dictyate or resting phase is small on the first day after birth, but increases on the second. Four different "waves" of degeneration of germ cells were observed. The first, affecting a small number of oogonia, occurs before the onset of meiosis, and is characterized by pyknosis. The second is characterized by degeneration of dividing oogonia which probably sets in before or at mitotic prophase. Such "atretic divisions" reach their peak at 18.5 days p.c, when the frequency of normal mitotic divisions is relatively low. The third affects germ cells after they have entered meiotic prophase (particularly at the pachytene stage); the chromosomes condense and the cytoplasm becomes eosinophil (referred to as "Z" cells). The fourth affects germ cells at the diplotene phase. Oogonial mitoses are associated with an increase in the population of germ cells from 12000 on day 14.5 to 71000 on day 17.5 p.c. The appearance of "atretic divisions" is largely responsible for the reduction of about 3000 in the number of normal germ cells between days 17.5 and 18.5. Successful mitotic divisions, on the other hand, account for the increase of about 4000 in the total number of germ cells during the same interval. From day 18.5 onwards, both the total number and the number of normal germ cells decreases steadily, first due to the occurrence of "atretic divisions" and later to degeneration of "Z" cells and atretic cells at diplotene. Thus by 2 days after birth, the peak number of normal germ cells (64000 at 17.5 days p.c.) has fallen to 19000, the total population (peak 75000 at 18.5 days p.c.) being reduced to 27000. The majority of germ cells appear to be eliminated from the ovary within 24 h of the onset of degeneration.