Prolonged dominance of follicles and reduced viability of bovine oocytes
Prolonged dominance of follicles and reduced viability of bovine oocytes
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DOI：
10.1530/jrf.0.1060039
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发表时间：
1996-01-01
期刊：
影响因子：
--
通讯作者：
Butler, WR
中科院分区：
文献类型：
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作者：
Revah, I;Butler, WR
已知延长牛卵泡的寿命会导致排卵和授精后的生育力降低。本研究考察了卵泡发育时间延长对卵母细胞活力的影响。在实验1中，抽吸延长卵泡组的6头奶牛在发乳周期的第4天（第1天=排卵）接受阴道孕酮释放装置，在第6天接受前列腺素F-2 α (40 mg)。超声引导下第13天进行卵泡抽吸。抽吸生长卵泡组的6头奶牛在第6天接受前列腺素F-2 α治疗，第7天接受卵泡抽吸治疗。在实验2中，用36 mg FSH-P刺激所有奶牛发育多个大卵泡进行研究。延长多卵泡组的3头奶牛接受与实验1相同的处理，但在第13天切除卵巢。生长多卵泡组的3头奶牛在第6天接受前列腺素F-2 α治疗，第7天切除卵巢。在两个实验中恢复的卵母细胞都被染色以显示核发育的阶段。所有来自抽吸延长和延长的多个卵泡的卵母细胞均显示扩增的卵丘细胞和浓缩的染色质分散在卵浆中，可能有生发囊破裂。抽吸生长卵泡和生长多卵泡的卵母细胞显示致密的卵丘细胞和完整的生发囊泡。两组卵泡的血浆雌二醇浓度均升高，直至卵母细胞恢复。抽吸延长卵泡组雌二醇在第6天溶体后升高，并保持高水平直至抽吸卵泡。相比之下，在fsh刺激的延长多卵泡组中，雌二醇在第8天降至痕量并保持低水平。各组卵泡液中雌二醇浓度与血浆浓度一致。来自延长的优势卵泡的牛卵母细胞在体内经历过早成熟，这可能解释了在其他研究中观察到的当与黄体酮同步排卵延长卵泡寿命时生育能力差的原因。
Prolonging the lifespan of bovine follicles is known to result in reduced fertility after ovulation and insemination. In this study, the effect of prolonged development of follicles on oocyte viability was examined. In Expt 1, six cows in the aspirated-prolonged-follicle group received a vaginal progesterone releasing device on day 4 of the oestrous cycle (day 1=ovulation) and prostaglandin F-2 alpha (40 mg) on day 6. Ultrasound-guided follicular aspiration was performed on day 13. Six cows in the aspirated-growing-follicle group received prostaglandin F-2 alpha on day 6, and follicular aspiration on day 7. In Expt 2, all cows were stimulated with 36 mg FSH-P to develop multiple large follicles for study. Three cows in the prolonged-multiple-follicle group received the same treatment as did cows in Expt 1, but were ovariectomized on day 13. Three cows in the growing-multiple-follicle group received prostaglandin F-2 alpha on day 6 and were ovariectomized on day 7. Oocytes recovered in both experiments were stained to reveal the stage of nuclear development. All oocytes from aspirated-prolonged and prolonged-multiple follicles showed expanded cumulus cells and condensed chromatin dispersed in the ooplasm, with possible germinal vesicle breakdown. Oocytes from aspirated-growing and growing-multiple follicles showed compact cumulus cells and an intact germinal vesicle. Plasma concentrations of oestradiol in both growing follicle groups increased until oocyte recovery. Oestradiol in the aspirated-prolonged-follicle group increased after luteolysis on day 6 and remained high until follicular aspiration. In contrast, in the FSH-stimulated prolonged-multiple-follicle group, oestradiol fell to trace amounts on day 8 and remained low. Oestradiol concentrations in follicular fluid were consistent with plasma concentrations for all groups. Bovine oocytes from prolonged dominant follicles undergo premature maturation in vivo, which perhaps accounts for the poor fertility observed in other studies when oestrous synchronization with progestins prolongs follicle lifespan.