Blondin P, Coenen K, Guilbault L A, Sirard M A
Département des Sciences Animales, Université Laval Québec, Canada.
Theriogenology. 1996 Nov 1;46(7):1191-203. doi: 10.1016/s0093-691x(96)00290-7.
This study was done to determine if different superovulatory regimens could have an effect on the percentage of embryos produced using IVM/IVF/IVC. Cyclic heifers (n = 22) were superovulated between Days 8 and 12 of the estrous cycle with 4, 6 or 8 constant doses of FSH-P (4 mg each, twice daily) +/- the addition of 1 mg prostaglandin 24 h before slaughter. Ovaries from these superovulated cows and from untreated cows were collected and the follicles dissected. Oocytes were classified according to the appearance of their cumulus and cytoplasm. Individual culture as well as group culture were performed but an individual culture reduced the percentage of oocytes developing into embryos for both untreated and superovulated animals. The results indicated that despite the superovulation regimen the developmental competence of the oocytes collected was lower (0 to 15% embryos) than that of oocytes from untreated animals (20 to 34% embryos). Small follicles ( < or = 2.7 mm) yielded mostly oocytes with an incomplete or partially expanded cumulus investment that never developed into an embryo. Differences in the morphology of the oocytes from medium (2.7 to 8 mm) and large ( > or = 8 mm) follicles were apparent, but equal developmental rates were obtained between all classes of oocytes (12 and 8% embryos, respectively). Follicular atresia was reduced significantly after superovulation (81% nonatretic follicles in treated vs 42% nonatretic follicles in untreated animals); however oocytes from atretic and slightly atretic follicles developed similarly to those from nonatretic follicles. These results suggest that although superovulation increases follicular size and decreases atresia, these conditions are not sufficient to confer developmental competence on the oocytes.
本研究旨在确定不同的超排方案是否会对经体外成熟（IVM）/体外受精（IVF）/体外培养（IVC）产生的胚胎百分比产生影响。在发情周期的第8至12天，对22头周期性小母牛用4、6或8剂恒定剂量的促卵泡素-P（FSH-P，每剂4毫克，每日两次）进行超排，在屠宰前24小时±添加1毫克前列腺素。收集这些超排母牛和未处理母牛的卵巢并解剖卵泡。根据卵丘和细胞质的外观对卵母细胞进行分类。进行了个体培养和群体培养，但个体培养降低了未处理和超排动物中发育成胚胎的卵母细胞百分比。结果表明，尽管采用了超排方案，但所收集卵母细胞的发育能力（胚胎率0至15%）低于未处理动物的卵母细胞（胚胎率20至34%）。小卵泡（≤2.7毫米）产生的卵母细胞大多具有不完全或部分扩展的卵丘包裹，从未发育成胚胎。中等大小（2.7至8毫米）和大卵泡（≥8毫米）的卵母细胞在形态上存在明显差异，但所有类别卵母细胞的发育率相同（分别为12%和8%的胚胎率）。超排后卵泡闭锁显著减少（处理组81%的卵泡无闭锁，未处理组为42%）；然而，闭锁和轻度闭锁卵泡的卵母细胞发育情况与未闭锁卵泡的卵母细胞相似。这些结果表明，尽管超排增加了卵泡大小并减少了闭锁，但这些条件不足以赋予卵母细胞发育能力。
