Fernandez J, Bruno-Galarraga M M, Soto A T, de la Sota R L, Cueto M I, Lacau I M, Gibbons A E
Laboratorio de Reproducción de Rumiantes Menores, INTA Bariloche, San Carlos de Bariloche, Argentina.
Laboratorio de Reproducción de Rumiantes Menores, INTA Bariloche, San Carlos de Bariloche, Argentina.
Theriogenology. 2018 Jan 1;105:184-188. doi: 10.1016/j.theriogenology.2017.09.020. Epub 2017 Sep 23.
We determined the effect of GnRH or hCG treatment on day 4 post-time artificial insemination (FTAI) on the formation of accessory corpora lutea (acc-CL) and on the concentration of serum progesterone (P) in sheep. Multiparous adult Merino ewes (n = 36) were synchronized for estrus using double injection of PGF2α agonist (125 μg Cloprostenol) with an interval of 14 days. At 53-56 h after the second PG application, FTAI was performed. On day 4 post FTAI, ewes were either treated with analogue of GnRH (4 μg buserelin; n = 12) or hCG (300 IU, hCG; n = 12) or saline solution (1 ml; Control; n = 12). Two laparoscopic ovarian examinations were performed on days 4 and 10 post FTAI. In the first observation, we determined the number of post ovulation corpora lutea (po-CL) and the site, number and diameter of follicles present in both ovaries. In the second laparoscopy, we observed the number of po-CL and acc-CL. The sizes of the follicles that generated the acc-CL were determined according to the position of the follicles observed in the first laparoscopy. Serum P concentration was determined on days 4, 7, 10, 13, 17 and 21 post FTAI by chemiluminescence. A similar follicular population in size and number was observed in the three experimental groups prior to the beginning of treatments (Follicles 2 mm: 6.4 ± 3.7, 3 mm: 3.0 ± 2.3, 4 mm: 1.1 ± 0.5, 5 mm: 1.4 ± 0.8; P ˃ 0.05). The formation of 1.0 ± 0.4 and 1.1 ± 0.3 acc-CL was observed in the GnRH and hCG groups, respectively (P ˃ 0.05), but was not observed in the Control group (P < 0.05). Follicle sizes from which acc-CL generated were 3, 4 and 5 mm and did not differ between hormonal treatments (P ˃ 0.05). The hCG group had higher mean concentrations of P on days 7, 10, 13 and 17 post FTAI compared with the GnRH group and the Control group (P < 0.05), while no differences were observed between these two latter groups (P > 0.05). Mean P concentrations in ewes treated with hCG showed no differences according to the size of the follicle from which acc-CL were generated (P ˃ 0.05). In conclusion, administration of hCG or GnRH on day 4 post FTAI induced the formation of one acc-CL from follicles of 3, 4 or 5 mm, indistinctly. However, serum P concentration increased significantly only in the hCG group. The serum P concentrations of acc-CL that originated from different follicle sizes did not differ.
我们确定了在人工授精（FTAI）后第4天给予促性腺激素释放激素（GnRH）或人绒毛膜促性腺激素（hCG）对绵羊副黄体（acc-CL）形成及血清孕酮（P）浓度的影响。经产成年美利奴母羊（n = 36）采用间隔14天两次注射前列腺素F2α激动剂（125μg氯前列醇）的方法进行发情同步化处理。在第二次注射PG后53 - 56小时进行FTAI。FTAI后第4天，母羊分别接受GnRH类似物（4μg布舍瑞林；n = 12）或hCG（300IU，hCG；n = 12）或生理盐水（1ml；对照组；n = 12）处理。在FTAI后第4天和第10天进行两次腹腔镜卵巢检查。在第一次观察中，我们确定排卵后黄体（po-CL）的数量以及两侧卵巢中卵泡的位置、数量和直径。在第二次腹腔镜检查中，我们观察po-CL和acc-CL的数量。根据第一次腹腔镜检查中观察到的卵泡位置确定产生acc-CL的卵泡大小。在FTAI后第4、7、10、13、17和21天通过化学发光法测定血清P浓度。在处理开始前，三个实验组观察到大小和数量相似的卵泡群体（直径2mm的卵泡：6.4±3.7个，3mm的卵泡：3.0±2.3个，4mm的卵泡：1.1±0.5个，5mm的卵泡：1.4±0.8个；P＞0.05）。在GnRH组和hCG组中分别观察到1.0±0.4个和1.1±0.3个acc-CL的形成（P＞0.05），但在对照组中未观察到（P＜0.05）。产生acc-CL的卵泡大小为3、4和5mm，不同激素处理之间无差异（P＞0.05）。与GnRH组和对照组相比，hCG组在FTAI后第7、10、13和17天的血清P平均浓度更高（P＜0.05），而后两组之间未观察到差异（P＞0.05）。接受hCG处理的母羊，其血清P平均浓度根据产生acc-CL的卵泡大小无差异（P＞0.05）。总之，FTAI后第4天给予hCG或GnRH均可诱导3、4或5mm卵泡形成一个acc-CL，无明显差异。然而，仅hCG组的血清P浓度显著升高。源自不同大小卵泡的acc-CL的血清P浓度无差异。
