van de Leemput E E, Vos P L, Hyttel P, van den Hurk R, Bevers M M, van der Weijden G C, Dieleman S J
Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
Theriogenology. 2001 Jan 15;55(2):573-92. doi: 10.1016/s0093-691x(01)00427-7.
The aim of this study was to investigate whether prolongation of the period of preovulatory follicular development after superovulation reduces heterogeneity of oocytes of stimulated follicles with respect to the potential to mature, to ovulate, to be fertilized and to develop into embryos. Heifers were treated with eCG on Day 10 and prostaglandin (PG) 48 h later. At the time of eCG administration some of the heifers received a norgestomet implant (N) to suppress the LH surge. After 96 to 104 h, N was removed and an LH surge was induced with GnRH (G) (N/G); the other animals served as controls. Matured oocytes (Experiment A: n=9, 139 [N/G] and 11, 125 [Control] heifers, oocytes), zygotes and oviducts (Experiment B: n=8, 44 [N/G] and 9, 72 [Control] heifers, zygotes) and embryos (Experiment C: n=11, 205 [N/G] and 11, 165 [Control] heifers, embryos) were collected at 22 to 26 h, 38 to 52 h and 7 days after the LH surge, respectively. Hatched blastocyst formation of matured oocytes (Experiment A) was analyzed after 11 days of IVC after IVF. In vivo fertilization rate of zygotes, the presence of periodic acid-Schiff (PAS) positive granules in the oviduct (Experiment B) and stage of development of embryos (Experiment C) were analyzed stereomicroscopically. The mean interval between PG and the LH surge was 53.8+/-3 (SD) (N/G) vs. 42.4+/-4 h (Control). The maximum peripheral estradiol-17beta concentration (529+/-36 [SEM] [N/G] vs. 403+/-17 pmol/L [Control]) and the response to superovulation (25.4+/-2 [N/G] vs. 18.7+/-2 [Control]) were higher in N/G than in Control heifers. Hatched blastocyst formation rate (37.4 [N/G] vs. 33.6% [Control]), in vivo fertilization rate (69.0+/-14 [N/G] vs. 73.0+/-10% [Control]) and the yield of total embryos (3.8+/-1 [N/G] vs. 5.6+/-2 [Control]) did not differ between groups. The percentage of heifers with abundant PAS-positive granules in the distal ampulla (0 [N/G] vs. 31% [Control]) was reduced after N/G treatment. Prolongation of the period of preovulatory follicular development increased the number of mature follicles and ovulations but did not result in higher embryo yield, possibly because of an impaired oviductal environment.
本研究的目的是调查超排卵后排卵前卵泡发育时间的延长是否会降低受刺激卵泡的卵母细胞在成熟、排卵、受精及发育成胚胎潜力方面的异质性。在第10天给小母牛注射eCG，48小时后注射前列腺素（PG）。在注射eCG时，部分小母牛植入诺孕美特（N）以抑制促黄体生成素（LH）峰。96至104小时后，取出N并用促性腺激素释放激素（GnRH）诱导LH峰（N/G）；其他动物作为对照。分别在LH峰后22至26小时、38至52小时和7天收集成熟卵母细胞（实验A：n = 9，139头 [N/G] 和11，125头 [对照] 小母牛，卵母细胞）、受精卵和输卵管（实验B：n = 8，44头 [N/G] 和9，72头 [对照] 小母牛，受精卵）以及胚胎（实验C：n = 11，205头 [N/G] 和11，165头 [对照] 小母牛，胚胎）。体外受精后11天分析成熟卵母细胞（实验A）的孵化囊胚形成情况。立体显微镜下分析受精卵的体内受精率、输卵管中过碘酸 - 希夫（PAS）阳性颗粒的存在情况（实验B）以及胚胎的发育阶段（实验C）。PG与LH峰之间的平均间隔为53.8±3（标准差）（N/G）对比42.4±4小时（对照）。N/G组小母牛的外周雌二醇 - 17β最大浓度（529±36 [标准误] [N/G] 对比403±17 pmol/L [对照]）和对超排卵的反应（25.4±2 [N/G] 对比18.7±2 [对照]）高于对照组。两组间孵化囊胚形成率（37.4 [N/G] 对比33.6% [对照]）、体内受精率（69.0±14 [N/G] 对比73.0±10% [对照]）以及总胚胎产量（3.8±1 [N/G] 对比5.6±2 [对照]）无差异。N/G处理后，壶腹远端有丰富PAS阳性颗粒的小母牛百分比降低（0 [N/G] 对比31% [对照]）。排卵前卵泡发育时间的延长增加了成熟卵泡和排卵的数量，但并未导致更高的胚胎产量，这可能是由于输卵管环境受损所致。
