Takagi M, Choi Y H, Kamishita H, Acosta T J, Wijayagunawardane M P, Miyamoto A, Miyazawa K, Sato K
Laboratory of Theriogenology, Faculty of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan.
Anim Reprod Sci. 1998 May 15;51(3):195-203. doi: 10.1016/s0378-4320(98)00070-0.
The present study was conducted with ovaries to evaluate the effect of the presence of a cystic follicle and its steroid hormone concentration on the oocyte recovery rates, oocyte morphology and in vitro maturation of the oocytes from coexisting small follicles. Ovaries, each bearing a follicular cyst (containing > 10 ml of follicular fluids, > 3 cm in diameter, and without a functional corpus luteum), were collected from each of the 26 Holstein cows from a local slaughterhouse. Small follicles (1-7 mm) from these ovaries were aspirated and their cumulus-oocyte complexes (COCs) classified into one of 5 groups (A to E), depending on oocyte and cumulus cell morphologies. Those oocytes with compact cumulus cells were cultured and their maturation rates determined. Concentrations of estradiol-17 beta (E2) and progesterone (P4) were measured in cystic follicular fluid using double antibody enzyme immunoassays (EIA). The morphology of the COCs and maturation rates of the oocytes were then evaluated using two comparisons. In first comparison, the left and right ovaries obtained from an individual cow were considered as a pair, with each pair being divided into two groups depending on the presence or absence of an E2 dominant or P4 dominant cystic follicle in one or another of the ovaries: E2 dominant cows; and P4 dominant cows. Oocytes collected from the ovaries of cyclic cows at follicular, luteal and post-ovulatory stages served as controls. The oocyte recovery rates, oocyte morphologies and oocyte maturation rates were independent of the presence or absence of a coexisting cystic follicle, or its steroid hormone classification or concentration. In the second comparison, each ovary was consider individually and divided into one of the two classes, depending on the presence or absence of a cystic follicle. Those ovaries with cystic follicles were then divided into three subclasses on the basis of E2 and P4 concentrations in the cystic follicular fluids: P4 dominant (P4/E2 ratio > 1); E2 dominant (P4/E2 ratio < 1); and both P4 and E2 dominant follicles present. The numbers of oocytes obtained from an ovary, their morphology and their maturation rates were not significantly different in the presence or absence of a coexisting cystic follicle. Moreover, the number of the oocytes aspirated from an ovary, their morphology and their maturation rates in small follicles coexisting with P4 dominant, E2 dominant and both P4 and E2 dominant cystic follicles were also not different. These results suggested that neither the presence of a cystic follicle in a cow's ovary nor the cyst's steroid hormone concentrations affected the oocyte recovery rate, oocyte morphology and maturation rates of the coexisting small follicles.
本研究以卵巢为对象，评估囊性卵泡的存在及其类固醇激素浓度对共存小卵泡中卵母细胞回收率、卵母细胞形态及卵母细胞体外成熟的影响。从当地一家屠宰场的26头荷斯坦奶牛中，每头牛采集一个带有卵泡囊肿（卵泡液>10毫升，直径>3厘米，且无功能性黄体）的卵巢。从这些卵巢中抽吸直径为1 - 7毫米的小卵泡，并根据卵母细胞和卵丘细胞形态将其卵丘 - 卵母细胞复合体（COC）分为5组（A至E）。将那些卵丘细胞致密的卵母细胞进行培养并测定其成熟率。使用双抗体酶免疫分析法（EIA）测定囊性卵泡液中雌二醇 - 17β（E2）和孕酮（P4）的浓度。然后通过两种比较方式评估COC的形态和卵母细胞的成熟率。在第一次比较中，将从每头奶牛获得的左右卵巢视为一对，根据其中一个或另一个卵巢中是否存在E2主导或P4主导的囊性卵泡，将每对卵巢分为两组：E2主导型奶牛；和P4主导型奶牛。从处于卵泡期、黄体期和排卵后期的周期性奶牛卵巢中采集的卵母细胞作为对照。卵母细胞回收率、卵母细胞形态和卵母细胞成熟率与共存囊性卵泡的有无、其类固醇激素分类或浓度无关。在第二次比较中，单独考虑每个卵巢，并根据是否存在囊性卵泡将其分为两类。然后根据囊性卵泡液中E2和P4的浓度，将那些有囊性卵泡的卵巢分为三个亚类：P4主导型（P4/E2比值>1）；E2主导型（P4/E2比值<1）；以及同时存在P4和E2主导卵泡。在存在或不存在共存囊性卵泡的情况下，从一个卵巢获得的卵母细胞数量、其形态及其成熟率均无显著差异。此外，在与P4主导型、E2主导型以及同时存在P4和E2主导型囊性卵泡共存的小卵泡中，抽吸的卵母细胞数量、其形态及其成熟率也没有差异。这些结果表明，奶牛卵巢中囊性卵泡的存在及其囊肿的类固醇激素浓度均不会影响共存小卵泡的卵母细胞回收率、卵母细胞形态和成熟率。
