O'Shea J D, McCoy K
Department of Veterinary Preclinical Sciences, University of Melbourne, Parkville, Australia.
J Reprod Fertil. 1988 May;83(1):107-17. doi: 10.1530/jrf.0.0830107.
Changes in luteal weight from about Day 20 to near term, and in quantitative histology as assessed by ultrastructural morphometry and light microscopic counts of mitosis and cell death on Days 30, 60, 100 and 142, were studied in 168 pregnant ewes. Luteal weight (mean +/- s.d.) remained constant at 0.56 +/- 0.11 g until Day 120, and fell thereafter to reach 0.31 +/- 0.11 g after Day 140 (P less than 0.01). Up to Day 100, quantitative aspects of the composition of the luteal tissue showed no significant change, and values for volume density, cytoplasmic:nuclear ratio, cell number/mm3 and cell volume were comparable to values previously obtained for corpora lutea (CL) of the cycle. By Day 142 structural evidence of luteal regression was present, but regressive changes were much more marked in some CL than others. Mitosis was seen in a few cells (0.02-0.04%) on all of the days studied, but never in large luteal cells. Cell death was rarely seen up to Day 100, but had increased in incidence by Day 142 (P less than 0.01). Luteal progesterone content, 55.2 +/- 15.9 nmol/g on Day 30, was not significantly changed on Days 60, 100 or 142. It is concluded that (1) structural regression of the CL of pregnancy does not begin until much later than the time (about Day 50) when pregnancy ceases to depend on the CL; (2) structural luteal regression begins before parturition, but its time of onset and/or rate of progression vary widely between animals; and (3) large and small luteal cells remain as distinctive populations throughout pregnancy, and their numbers at all stages can be accounted for by survival of the cells which differentiate during the genesis of the CL.
对168只怀孕母羊研究了从约第20天到接近足月时黄体重量的变化，以及通过超微结构形态计量学和在第30、60、100和142天对有丝分裂和细胞死亡进行光镜计数评估的定量组织学变化。黄体重量（平均值±标准差）在第120天前保持恒定，为0.56±0.11 g，此后下降，在第140天后降至0.31±0.11 g（P<0.01）。直到第100天，黄体组织组成的定量方面没有显著变化，体积密度、细胞质与细胞核比率、每立方毫米细胞数和细胞体积的值与之前在周期黄体（CL）中获得的值相当。到第142天，出现了黄体退化的结构证据，但一些CL中的退化变化比其他的更为明显。在所有研究的天数中，在少数细胞（0.02 - 0.04%）中可见有丝分裂，但从未在大型黄体细胞中见到。直到第100天很少见到细胞死亡，但到第142天发生率增加（P<0.01）。第30天时黄体孕酮含量为55.2±15.9 nmol/g，在第60、100或142天没有显著变化。得出的结论是：（1）怀孕黄体的结构退化直到比怀孕不再依赖黄体的时间（约第50天）晚得多才开始；（2）黄体结构退化在分娩前开始，但其开始时间和/或进展速度在动物之间差异很大；（3）在整个怀孕期间，大型和小型黄体细胞仍然是不同的群体，并且它们在所有阶段的数量可以通过在黄体形成过程中分化的细胞的存活来解释。
