Clinic for Cattle, School of Veterinary Medicine Hannover, Hannover, Germany.
Theriogenology. 2010 Jan 15;73(2):242-9. doi: 10.1016/j.theriogenology.2009.08.014.
The goal of this study was to determine the effects of the length of the preovulatory phase on genital blood flow and mRNA expression of endometrial hormone receptors in cattle (Bos Taurus). Ovulation was synchronized in 50 Holstein-Friesian cows using a modified Ovsynch (ovulation synchronization) protocol, in which the second gonadotropin-releasing hormone (GnRH) administration was given 40h (G40, n=17) or 60h (G60, n=16) after the prostaglandin F(2alpha) (PGF(2alpha)) administration. The third group (S, n=17) did not receive a second GnRH administration. Transrectal color Doppler examinations were carried out 24h before (Day -1) and on Day 7 after ovulation (Day 0). Follicular size (FS) and luteal size (CLS) were quantified by measuring the areas of these structures on cross-sectional B-mode ultrasound images. Follicular blood flow (FB) and luteal blood flow (CLB) were quantified by determining the colored areas of these structures. Uterine blood flow was measured using the time-averaged maximum velocities (TAMVs) and the pulsatility indices (PIs) of both uterine arteries. Endometrial mRNA transcript abundance of estrogen receptors alpha and beta as well as oxytocin and progesterone receptor were determined on Days -1 and 7 in G40 and G60 cows. In all cows, plasma progesterone (P(4)) values were measured on Day 7. On Day -1, FS and FB values were lower (P < or = 0.05) in G40 cows compared with those in S cows but did not differ (P>0.05) between G60 cows on the one hand and G40 cows and S cows, respectively, on the other hand. On Day 7, CLS and P(4) did not differ (P>0.05) between cows of Groups G40, G60, and S; CLB was lower (P< or =0.05) in G40 cows than in G60 and S cows, but no difference (P>0.05) occurred between G60 and S cows. The uterine TAMV and PI values did not differ among the three groups (P>0.05). Gene expression of hormone receptors did not differ (P>0.05) between Groups G40 and G60 on Days -1 and 7. Results of this study indicate that a shortened preovulatory follicle phase primarily affects ovarian but not the measured uterine events in cows undergoing synchronization of ovulation.
本研究的目的是确定促黄体素释放激素（GnRH）在排卵前相的长度对牛（Bos Taurus）生殖血液流动和子宫内膜激素受体 mRNA 表达的影响。通过改良的 Ovsynch（排卵同步）方案，使用前列腺素 F(2alpha)（PGF(2alpha)）后 40h（G40，n=17）或 60h（G60，n=16）给予第二次 GnRH 给药，使 50 头荷斯坦弗里森奶牛同步排卵。第三组（S，n=17）未给予第二次 GnRH 给药。在排卵前 24h（-1 天）和排卵后第 7 天（0 天）进行经直肠彩色多普勒检查。通过测量横断 B 型超声图像中这些结构的面积来定量卵泡大小（FS）和黄体大小（CLS）。通过确定这些结构的彩色区域来定量卵泡血流（FB）和黄体血流（CLB）。使用子宫动脉的时间平均最大速度（TAMV）和搏动指数（PI）测量子宫血流。在 G40 和 G60 奶牛的-1 天和 7 天测量雌激素受体 alpha 和 beta 以及催产素和孕激素受体的子宫内膜 mRNA 转录丰度。在所有奶牛中，在第 7 天测量血浆孕酮（P(4)）值。在-1 天，G40 奶牛的 FS 和 FB 值低于 S 奶牛（P <或= 0.05），但 G60 奶牛与 G40 奶牛和 S 奶牛之间没有差异（P>0.05）。在第 7 天，G40、G60 和 S 组奶牛之间的 CLS 和 P(4)值没有差异（P>0.05）；G40 奶牛的 CLB 低于 G60 和 S 奶牛（P<或=0.05），但 G60 和 S 奶牛之间没有差异（P>0.05）。三组之间的子宫 TAMV 和 PI 值没有差异（P>0.05）。-1 天和 7 天，G40 和 G60 组之间的激素受体基因表达没有差异（P>0.05）。本研究结果表明，在接受排卵同步的奶牛中，促黄体素释放激素（GnRH）在排卵前相的缩短主要影响卵巢，而不是测量的子宫事件。
