Smith L C, Olivera-Angel M, Groome N P, Bhatia B, Price C A
Centre de recherche en reproduction animale, University of Montreal, St-Hyacinthe, Quebec, Canada.
J Reprod Fertil. 1996 Mar;106(2):193-9. doi: 10.1530/jrf.0.1060193.
The aim of these experiments was to determine whether the presence of a dominant follicle affects the developmental competence of oocytes from small antral follicles of cattle. In Expt 1, oocytes or follicular fluid samples were collected from follicles 2-7 mm in diameter before (day 3 of the oestrous cycle; n = 4) or after (days 6 and 7 of the oestrous cycle; n = 6) emergence of the first wave dominant follicle (verified by rectal ultrasonography). Five to ten follicles were aspirated for the determination of individual follicular fluid concentrations of oestradiol, progesterone, testosterone and dimeric inhibin; oocytes from the remaining follicles from each cow were pooled and developmental capacity assessed by in vitro fertilization and maturation. In Expt 2, ovaries containing a young corpus luteum and with or without a large oestrogen-active follicle were collected from the abattoir. Follicular aspirates from small follicles in each pair of ovaries were pooled, and oocyte quality and steroid concentrations were determined. In Expt 1, small follicles obtained before emergence of the dominant follicle contained significantly more oestradiol than they did after emergence (19.5 +/- 1.5 versus 0.7 +/- 1.1 ng ml-1, respectively; P < 0.05), but there were no significant differences in concentrations of progesterone, testosterone or dimeric inhibin. The percentage of blastocysts obtained from oocytes collected before (12.1 +/- 9.0) or after emergence (11.8 +/- 7.0) of the dominant follicle did not differ significantly (P > 0.05). In Expt 2, follicular steroid concentrations did not differ in small follicles taken in the presence versus the absence of a large oestrogen-active follicle, and there were no differences in the developmental capacity of the oocytes. There were significant negative correlations between follicular oestradiol concentration and the percentage of blastocysts formed from two-cell (r = -0.90; P < 0.01) and eight-cell embryos (r = -0.65; P < 0.05). These data suggest that in cattle the developmental competence of oocytes from small antral follicles is not adversely affected by the presence of a dominant follicle.
这些实验的目的是确定优势卵泡的存在是否会影响牛小窦卵泡中卵母细胞的发育能力。在实验1中，在第一个卵泡波优势卵泡出现之前（发情周期第3天；n = 4）或之后（发情周期第6天和第7天；n = 6），从直径2 - 7毫米的卵泡中收集卵母细胞或卵泡液样本（通过直肠超声检查确认）。抽吸5至10个卵泡以测定卵泡液中雌二醇、孕酮、睾酮和二聚抑制素的个体浓度；将每头母牛剩余卵泡中的卵母细胞汇集在一起，通过体外受精和成熟来评估发育能力。在实验2中，从屠宰场收集含有新鲜黄体且有或没有大的雌激素活性卵泡的卵巢。将每对卵巢中小卵泡的卵泡抽吸物汇集在一起，测定卵母细胞质量和类固醇浓度。在实验1中，优势卵泡出现前获得的小卵泡所含雌二醇明显多于出现后（分别为19.5±1.5与0.7±1.1纳克/毫升；P < 0.05），但孕酮、睾酮或二聚抑制素的浓度没有显著差异。优势卵泡出现前（12.1±9.0）或出现后（11.8±7.0）收集到的卵母细胞所形成的囊胚百分比没有显著差异（P > 0.05）。在实验2中，存在或不存在大的雌激素活性卵泡时，小卵泡的卵泡类固醇浓度没有差异，卵母细胞的发育能力也没有差异。卵泡雌二醇浓度与二细胞（r = -0.90；P < 0.01）和八细胞胚胎（r = -0.65；P < 0.05）形成囊胚的百分比之间存在显著负相关。这些数据表明，在牛中，小窦卵泡中卵母细胞的发育能力不会受到优势卵泡存在的不利影响。
