Morphology of equine allantochorion at the tip of the pregnant horn.
The morphology of the equine allantochorion at the tip of the pregnant horn was studied in the membranes of 14 mares. The findings in the allantochorion at the tip of the pregnant horn were of two types; one was growth retardation (hypoplastic villi, tunica adventitia of the vessels resembling embryonal connective tissue and the extended spaces of remnants of the extraembryonic coelom), the other was placental hypoxia or ischaemia (parakeratosis, stratified squamous metaplasia, necrosis of the trophoblasts, thickening of the basement membrane and fibrous hyperplasia of villous stroma). It seems likely that hypoplastic villi are caused by disordered formation of the microcotyledon accompanying the progression of pregnancy.
Oikawa
M
M
Pathology Division, Equine Research Institute, Japan Racing Association, Tokyo.
Yoshihara
T
T
Kaneko
M
M
Yoshikawa
T
T
D000818:Animals; D002823:Chorion / Q000033:anatomy & histology*; D005260:Female; D006736:Horses / Q000033:anatomy & histology*; D007743:Labor, Obstetric; D011247:Pregnancy