Costine B A, Sayre B L, Inskeep E K
Division of Animal and Veterinary Sciences, West Virginia University, Morgantown,WV 26506-6108, USA.
Reproduction. 2001 Dec;122(6):883-7.
Experiments were performed to test the null hypotheses that embryonic survival is not affected by the presence of regressing corpora lutea in progestogen-supplemented ewes, and that the embryotoxic effects of regressing corpora lutea do not act locally on embryos in the uterine horn adjacent to the regressing corpora lutea. In Expt 1, laparotomies were performed on day 4 after mating, and progestogen supplementation was initiated and continued until pregnancy was diagnosed by ultrasonography on day 25. On day 4 after mating, ewes were lutectomized (n = 17) or sham lutectomized (n = 15), and injected (i.m.) with 5 mg PGF2alpha at 8 h intervals for 2 or 3 days. Controls (n = 14) were sham lutectomized and injected with saline as described above. Pregnancy rates did not differ in ewes treated with PGF2alpha for 2 rather than 3 days. Pregnancy rates were lower in ewes treated with PGF 2a compared with controls (P < 0.01). In ewes treated with PGF2alpha, lutectomy resulted in an increase in pregnancy rates (59%) compared with ewes subjected to sham lutectomy (33%; P < 0.05). In Expt 2, progestogen supplementation was initiated in the morning of day 4 after mating and continued until pregnancy diagnosis on day 25. In the afternoon of day 4, one ovary selected at random was lutectomized in ewes (n = 34) with at least one corpus luteum on each ovary, and the uterine horns were isolated by ligation to impede intraluminal transfer of luteal or uterine products that might initiate embryonic death. On days 5-8 after mating, equal numbers of ewes were injected i.m. with either saline or 5 mg PGF2alpha at 8 h intervals. Pregnancy rates did not differ between isolated uterine horns contralateral and ipsilateral to the regressing corpus luteum; however, pregnancy rates were lower in PGF2alpha-treated ewes than in saline-treated ewes (34 and 77%; P < 0.05). In conclusion, regressing corpora lutea exert an embryotoxic effect; however, there is no evidence that this effect occurs through systemic pathways.
进行了实验以检验零假设，即补充孕激素的母羊中，退化黄体的存在不会影响胚胎存活，以及退化黄体的胚胎毒性作用不会局部作用于与退化黄体相邻的子宫角内的胚胎。在实验1中，在交配后第4天进行剖腹手术，开始补充孕激素并持续至第25天通过超声诊断怀孕。在交配后第4天，对母羊进行黄体切除术（n = 17）或假黄体切除术（n = 15），并每隔8小时肌肉注射5 mg PGF2α，持续2或3天。对照组（n = 14）进行假黄体切除术，并按上述方法注射生理盐水。用PGF2α处理2天而非3天的母羊怀孕率没有差异。与对照组相比，用PGF 2α处理的母羊怀孕率较低（P < 0.01）。在用PGF2α处理的母羊中，黄体切除术导致怀孕率增加（59%），而假黄体切除的母羊怀孕率为33%（P < 0.05）。在实验2中，在交配后第4天上午开始补充孕激素并持续至第25天进行怀孕诊断。在第4天下午，对每个卵巢至少有一个黄体的母羊（n = 34）随机选择一个卵巢进行黄体切除术，并通过结扎隔离子宫角，以阻止可能引发胚胎死亡的黄体或子宫产物的腔内转移。在交配后第5 - 8天，相同数量的母羊每隔8小时肌肉注射生理盐水或5 mg PGF2α。与退化黄体对侧和同侧的隔离子宫角之间的怀孕率没有差异；然而，用PGF2α处理的母羊怀孕率低于用生理盐水处理的母羊（34%和77%；P < 0.05）。总之，退化黄体具有胚胎毒性作用；然而，没有证据表明这种作用是通过全身途径发生的。
