Vanderhyden B C, Armstrong D T
Department of Physiology, University of Western Ontario, London, Canada.
Biol Reprod. 1989 Apr;40(4):720-8. doi: 10.1095/biolreprod40.4.720.
Immature oocytes were collected from immature female rats (60-65 g) 40 h after injection with 6 IU pregnant mare's serum gonadotropin (PMSG). Oocytes were matured cumulus-intact (CI) or cumulus-free (CF) in medium supplemented with 0.5% bovine serum albumin (BSA) or 5-20% serum for periods of up to 24 h. After assessment for nuclear maturation, the oocytes were exposed to epididymal sperm for fertilization in vitro. In vitro-matured and ovulated oocytes undergoing fertilization were transferred to unilaterally pregnant recipients for embryonic and fetal development. The presence of cumulus cells and serum shortened (by 2 h) the time required for polar body emission by in vitro-matured oocytes and also helped to increase significantly the penetrability of the oocytes by spermatozoa. A high proportion (45.6%) of fertilized oocytes showed evidence of abnormal fertilization following maturation in the absence of cumulus cells. Oocytes matured CI before fertilization were able to develop to viable fetuses (57.8%) in proportions similar to ovulated oocytes (55.0%) after in vitro fertilization. These findings indicate an essential role for cumulus cells in promoting normal cytoplasmic maturation of oocytes necessary for pronuclear formation and subsequent developmental capability.
在向未成熟雌性大鼠（60 - 65克）注射6国际单位孕马血清促性腺激素（PMSG）40小时后，收集未成熟卵母细胞。卵母细胞在补充有0.5%牛血清白蛋白（BSA）或5 - 20%血清的培养基中进行有卵丘完整（CI）或无卵丘（CF）成熟培养，培养时间长达24小时。在评估核成熟后，将卵母细胞暴露于附睾精子进行体外受精。将体外成熟并排卵且正在受精的卵母细胞转移到单侧妊娠的受体中进行胚胎和胎儿发育。卵丘细胞和血清的存在缩短了（2小时）体外成熟卵母细胞排出极体所需的时间，并且还显著提高了精子对卵母细胞的穿透能力。在无卵丘细胞的情况下成熟后，高比例（45.6%）的受精卵显示出异常受精的迹象。受精前CI成熟的卵母细胞能够发育成活胎（57.8%），其比例与体外受精后排卵的卵母细胞（55.0%）相似。这些发现表明卵丘细胞在促进卵母细胞正常细胞质成熟方面起着至关重要的作用，而这对于原核形成和随后的发育能力是必需的。
