Kirkpatrick B W, Rutledge J J
Department of Meat and Animal Science, University of Wisconsin, Madison 53706.
Biol Reprod. 1988 Dec;39(5):1027-31. doi: 10.1095/biolreprod39.5.1027.
An experiment was conducted to test effects of prenatal and postnatal fraternity size (size of litter in which an individual develops prenatally or is reared postnatally) on ovarian development in mice. Fraternity size treatments were created by standardizing sizes of prenatal and postnatal fraternities in which mice were gestated and reared. Prenatal fraternity size was standardized by surgery on Day 9 of gestation to 6, 10, and 14 fetuses. Postnatal fraternity size was standardized by randomly assigning pups to litters of 5, 10, or 15 pups within 24 h of birth. Female pups were killed at either 3 or 20 wk of age and right ovaries were prepared for histology. Follicles were classified by size and morphology, and numbers of follicles in each class were tabulated. Interaction of postnatal fraternity size and age was observed for number of antral follicles (p less than 0.05). Mice reared in small postnatal fraternities had more antral follicles at weaning (3 wk) and fewer antral follicles at maturity (20 wk of age) than mice reared in large postnatal fraternities. No effect of either prenatal or postnatal fraternity size on other follicle populations was observed (p greater than 0.20). Numbers of Type 2 (primordial), Type 3a, and Type 3b follicles changed with age (p less than 0.01); numbers of primordial follicles declined with age, but numbers of Type 3a and 3b follicles increased. A hypothesis of a negative association between postnatal fraternity size and number of antral follicles at 3 wk of age was supported, but a hypothesis of a positive association between fraternity size and number of primordial follicles was not supported.
进行了一项实验，以测试产前和产后同胞规模（个体产前发育或产后饲养的窝仔规模）对小鼠卵巢发育的影响。通过标准化小鼠妊娠和饲养的产前和产后同胞规模来设置同胞规模处理组。产前同胞规模通过在妊娠第9天进行手术，使每个子宫内的胎儿数量分别为6只、10只和14只来实现标准化。产后同胞规模通过在出生后24小时内将幼崽随机分配到5只、10只或15只幼崽的窝中来实现标准化。雌性幼崽在3周龄或20周龄时处死，取右侧卵巢用于组织学分析。根据卵泡大小和形态对卵泡进行分类，并统计每类卵泡的数量。观察到产后同胞规模和年龄之间对腔前卵泡数量存在交互作用（p小于0.05）。与在较大产后同胞规模中饲养的小鼠相比，在较小产后同胞规模中饲养的小鼠在断奶时（3周龄）有更多的腔前卵泡，而在成熟时（20周龄）有更少的腔前卵泡。未观察到产前或产后同胞规模对其他卵泡群体有影响（p大于0.20）。2型（原始）、3a型和3b型卵泡的数量随年龄变化（p小于0.01）；原始卵泡数量随年龄下降，但3a型和3b型卵泡数量增加。出生后同胞规模与3周龄时腔前卵泡数量呈负相关的假设得到支持，但同胞规模与原始卵泡数量呈正相关的假设未得到支持。
