Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Mexico, DF.
Anim Reprod Sci. 2010 Aug;121(1-2):124-30. doi: 10.1016/j.anireprosci.2010.05.015. Epub 2010 May 27.
The objective of this study was to monitor and compare the concentrations of equine chorionic gonadotropin (eCG), progesterone and estrone sulphate during normal and failed pregnancies of mares impregnated with donkey or horse semen, relating their individual endocrine profiles to the time of pregnancy loss, and to the histopathologic findings in the aborted fetuses and placenta. Mares (n=54) were used, 32 of them impregnated with donkey semen and 22 impregnated with horse semen. Blood samples were taken twice a week from Day 35 to 120 of pregnancy. Ultrasonographic observations of the fetus were carried out twice a week. The incidence of abortion in mares impregnated with donkey semen (30%) was greater (P<0.05) than the 5% observed in mares impregnated with horse semen. From Week 8 to the end of the sampling period, the mean progesterone concentrations of mares with normal mule pregnancies were less (P<0.05) than those of mares with normal pregnancies with equine fetuses. The concentrations of eCG were less (P<0.05) in mule pregnancies from Week 6. Estrone sulphate concentrations were only different (P<0.05) between types of pregnancy on Weeks 13 and 14, being in this case greater with the mule pregnancies. Most of the abortions of mule fetuses were associated with lesser progesterone concentrations than the average for mares with successful mule pregnancies. Four of the abortions of mule fetuses and the only abortion of horse fetus occurred in mares with lesser progesterone and very low eCG concentrations, and were classified as caused by luteal impairment secondary to eCG deficiency; estrone sulphate concentrations were less than normal or absent before these abortions. Two mares aborted after several weeks of low progesterone concentrations in the presence of eCG concentrations that were normal for mule pregnancies, suggesting primary luteal deficiency. In three mares carrying a mule fetus, the concentrations of progesterone and estrone sulphate decreased abruptly immediately before fetal death, suggesting luteolysis due to active prostaglandin F2 alpha (PGF2alpha) secretion. It is concluded that the greater incidence of abortion in mares impregnated by donkeys is associated with different kinds of luteal malfunction. Deficiency of eCG may be a primary cause of many of these cases, either by failing to stimulate enough luteal progesterone secretion and/or by failing to protect the corpora lutea (CL) of pregnancy from endogenous PGF2alpha secretion.
本研究的目的是监测和比较用驴或马精液人工授精的母马正常和失败妊娠期间的马绒毛膜促性腺激素（eCG）、孕酮和雌酮硫酸盐浓度，将其个体内分泌谱与妊娠丢失时间以及流产胎儿和胎盘的组织病理学发现相关联。使用了 54 匹母马，其中 32 匹用驴精液授精，22 匹用马精液授精。从妊娠第 35 天到第 120 天，每周两次采集血液样本。每周两次对胎儿进行超声观察。用驴精液授精的母马流产发生率（30%）高于用马精液授精的母马（5%）（P<0.05）。从第 8 周到采样结束时，正常骡驹妊娠母马的平均孕酮浓度（P<0.05）低于正常马驹妊娠母马。从第 6 周开始，eCG 浓度（P<0.05）在骡驹妊娠中较低。雌酮硫酸盐浓度仅在妊娠类型之间在第 13 和 14 周有所不同（P<0.05），在这种情况下，骡驹妊娠中浓度较高。大多数骡驹流产与成功骡驹妊娠的母马平均孕酮浓度较低有关。4 例骡驹流产和 1 例马驹流产发生在孕酮浓度较低且 eCG 浓度极低的母马中，被归类为由于 eCG 缺乏引起的黄体功能不全；在这些流产之前，雌酮硫酸盐浓度低于正常水平或不存在。2 匹母马在存在 eCG 浓度正常的情况下，孕酮浓度数周后下降，提示原发性黄体功能不全。在 3 匹怀有骡驹的母马中，孕酮和雌酮硫酸盐浓度在胎儿死亡前突然急剧下降，提示由于活性前列腺素 F2 alpha（PGF2alpha）分泌而黄体溶解。结论是，用驴授精的母马流产发生率较高与不同类型的黄体功能障碍有关。eCG 缺乏可能是许多此类病例的主要原因，要么是未能刺激足够的黄体孕酮分泌，要么是未能防止妊娠黄体从内源性 PGF2alpha 分泌中保护黄体。
