Hendriksen P J M, Gadella B M, Vos P L A M, Mullaart E, Kruip T A M, Dieleman S J
Department of Farm Animal Health, Utrecht University, 3508 TD Utrecht, The Netherlands.
Biol Reprod. 2003 Dec;69(6):2036-44. doi: 10.1095/biolreprod.103.019828. Epub 2003 Aug 20.
The present study aimed to test the generally accepted view that a follicular wave starts with follicles newly recruited from the population smaller than 3 mm, which later compete for dominance. According to this view, subordinate follicles are expected to be too atretic to join the next follicular wave. Ten cows were ovariectomized shortly prior to the LH surge, thus around the start of the first follicular wave of the cycle. Per cow, on average, 14.4 follicles of >/=3 mm were dissected. Follicular health was determined on the basis of four parameters: 1) judgment of the degree of atresia by stereomicroscope, 2) incidence of apoptotic nuclei among the granulosa cells, 3) estradiol and progesterone concentrations, and 4) insulin-like growth factor-I (IGF-I) binding proteins (IGFBPs)-2, -4, and -5 concentrations in the follicular fluid. In addition to the preovulatory follicle, 3.1 other follicles, mainly sized 3-4.5 mm, were found to be healthy based on the proportion of apoptotic nuclei, and concentrations of estradiol/progesterone, and IGFBPs. The ability of these follicles to respond with growth on the preovulatory and periovulatory FSH surges was supported by a comparison to the follicular population of four cows 31-68 h after the LH surge. The present results point to an alteration of the view on the follicular wave. The larger follicles during the first days of the follicular wave are, in general, derived from follicles that also joined the previous wave. A portion of these growing follicles are estradiol active and compete for dominance. Other growing follicles lack estradiol production and are probably derived from rather atretic follicles. The first newly recruited follicles do not reach the size of 3 mm before 31 h after the preovulatory FSH surge. At that time, the larger follicles are already competing for dominance.
本研究旨在验证一种普遍接受的观点，即卵泡波始于从小于3毫米的卵泡群体中新募集的卵泡，这些卵泡随后竞争优势地位。根据这一观点，次级卵泡预计会过度闭锁，无法进入下一个卵泡波。在促黄体生成素（LH）峰前不久，即周期的第一个卵泡波开始时，对10头母牛进行了卵巢切除。每头母牛平均解剖出14.4个直径大于或等于3毫米的卵泡。根据四个参数确定卵泡健康状况：1）通过体视显微镜判断闭锁程度；2）颗粒细胞中凋亡核的发生率；3）雌二醇和孕酮浓度；4）卵泡液中胰岛素样生长因子-I（IGF-I）结合蛋白（IGFBPs）-2、-4和-5的浓度。除排卵前卵泡外，根据凋亡核比例、雌二醇/孕酮浓度和IGFBPs浓度，发现3.1个其他卵泡（主要大小为3 - 4.5毫米）是健康的。与LH峰后31 - 68小时的4头母牛的卵泡群体相比，这些卵泡在排卵前和围排卵期促卵泡素（FSH）峰时生长的反应能力得到了支持。目前的结果表明对卵泡波的观点有所改变。卵泡波开始的头几天较大的卵泡通常来自也参与了前一个卵泡波的卵泡。这些生长中的卵泡一部分具有雌二醇活性并竞争优势地位。其他生长中的卵泡缺乏雌二醇产生，可能来自相当闭锁的卵泡。在排卵前FSH峰后31小时之前，第一批新募集的卵泡未达到3毫米大小。此时，较大的卵泡已经在竞争优势地位。
