Document Detail

Cell proliferation patterns during development of the equine placenta.
MedLine Citation:
PMID:  10645255     Owner:  NLM     Status:  MEDLINE    
Placentation involves considerable growth and reorganization of both maternal and fetal tissues. In this investigation, immunohistochemical localization of the proliferation marker Ki-67 antigen was used to monitor cell division during placentation in mares. Endometrial biopsies were obtained from eight mares between day 14 and day 26 of pregnancy and from eight anoestrous mares that had been treated with various combinations of progesterone and oestrogen. Samples of endometrium and fetal membranes were obtained from 19 mares carrying normal horse conceptuses between day 30 and day 250 of gestation and from three failing extraspecific donkey-in-horse pregnancies. Proliferation in the superficial strata of the endometrium was increased by day 18 of gestation and this effect could be mimicked by supplementing with oestradiol benzoate during the last 6 days of a prolonged period (18-36 days) of progesterone administration. Fetal chorionic girdle cells were proliferating vigorously at days 30-32 of gestation, but stopped dividing after they invaded the endometrium, while the trophoblast cells of the allantochorion showed an increase in mitotic activity after day 38. The luminal epithelium of the endometrium started to proliferate only after the primary villi of the true epitheliochorial placenta had been formed, and during days 58-70 this effect was seen only in the pregnant horn in which placentation was further advanced. During the second half of gestation, most of the mitotic activity was confined to the periphery of the microcotyledons which were still growing. In the donkey-in-horse pregnancies, proliferation rates of the maternal and fetal epithelial at day 70 of gestation were markedly reduced in areas of heavy endometrial lymphocyte infiltration and poor placentation. These results provide a basis for further studies on factors that influence invasive and non-invasive placentation.
C Gerstenberg; W R Allen; F Stewart
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of reproduction and fertility     Volume:  117     ISSN:  0022-4251     ISO Abbreviation:  J. Reprod. Fertil.     Publication Date:  1999 Sep 
Date Detail:
Created Date:  2000-02-03     Completed Date:  2000-02-03     Revised Date:  2005-11-17    
Medline Journal Info:
Nlm Unique ID:  0376367     Medline TA:  J Reprod Fertil     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  143-52     Citation Subset:  IM    
University of Cambridge, Department of Clinical Veterinary Medicine, Suffolk, UK.
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MeSH Terms
Biological Markers / analysis
Cell Division
Endometrium / cytology*
Estradiol / pharmacology
Extraembryonic Membranes / cytology
Gestational Age
Horses / physiology*
Placenta / physiology*
Pregnancy, Animal / physiology*
Progesterone / pharmacology
Trophoblasts / cytology
Reg. No./Substance:
0/Biological Markers; 50-28-2/Estradiol; 57-83-0/Progesterone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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