Bracher Verena, Mathias Susanna, Allen W R
Thoroughbred Breeders' Association Equine Fertility Unit, Mertoun Paddocks, Woodditton Road, Newmarket, Suffolk CB8 9BH, UK.
Equine Vet J. 1996 May;28(3):180-188. doi: 10.1111/j.2042-3306.1996.tb03771.x.
Placentation between 80 and 220 days of gestation was studied by measurement of fetal dimensions and gross, light and transmission and scanning electron microscopic examinations of the allantochorion and endometrium from 4 fertile mares with no, or very mild, endometrial histopathology and 6 subfertile Thoroughbred mares suffering varying degrees of age-related chronic degenerative endometritis (endometrosis). Spontaneously occurring twin gestation was observed in 3 animals. Several of the subfertile mares had endometrial cysts which showed 2 distinct features during pregnancy: those located near the lumenal surface of the endometrium showed no sign of microcotyledon development in both the endometrium and the opposed, flat and smooth allantochorion, whereas endometrial cysts located deeper in the stroma were covered by apparently normal glands and microcotyledons. Fetal dimensions were lower in the subfertile mares, but still within the reference range. Microcotyledon development appeared to be delayed and the chorionic macro- and microvilli looked shorter and blunter between 80 and 120 days in the 2 subfertile mares compared to the 2 fertile mares at the same gestational ages. At 120 days, the subfertile mare had significantly less microvilli per surface area than her fertile counterpart and her fetus weighed only half that from her counterpart, despite a similar crown-rump length. However, between 160 and 220 days the difference in microcotyledon development between the young fertile and old subfertile mares was much less marked, despite the continued existence of considerable numbers of distended 'gland nests' in the endometrium of the latter group.
通过测量胎儿尺寸以及对4匹具有正常或非常轻微子宫内膜组织病理学特征的可育母马和6匹患有不同程度年龄相关性慢性退行性子宫内膜炎（子宫内膜症）的亚可育纯种母马的尿囊绒毛膜和子宫内膜进行大体、光镜、透射电镜和扫描电镜检查，研究了妊娠80至220天期间的胎盘形成情况。在3只动物中观察到自然发生的双胎妊娠。几只亚可育母马有子宫内膜囊肿，这些囊肿在妊娠期间表现出两个明显特征：位于子宫内膜腔面附近的囊肿在子宫内膜和相对的扁平光滑尿囊绒毛膜中均未显示微叶发育迹象，而位于基质较深处的子宫内膜囊肿则被明显正常的腺体和微叶覆盖。亚可育母马的胎儿尺寸较低，但仍在参考范围内。与相同孕周的2匹可育母马相比，2匹亚可育母马在80至120天期间微叶发育似乎延迟，绒毛膜的大、微绒毛看起来更短更钝。在120天时，亚可育母马每表面积的微绒毛明显少于其可育对应物，尽管头臀长度相似，但其胎儿体重仅为对应物的一半。然而，在160至220天期间，年轻可育母马和老龄亚可育母马之间微叶发育的差异不太明显，尽管后一组子宫内膜中仍存在大量扩张的“腺体巢”。
