id	author	title	date	pages	extension	mime	words	sentence	flesch	summary	cache	txt
ct-9455	Stout, Tom 	Embryo-maternal communication during the establishment of equine pregnancy	2020	7	.pdf	application/pdf	5062	229	39	Although little is known about embryo and oviduct interaction, the microenvironment of the oviductal ampulla clearly plays an active role in supporting early development; indeed, although in vitro produced (IVP) equine embryos reach the blastocyst stage at a similar time to in vivo embryos (7 - 8 days postfertilization), at this stage they contain many fewer cells,10 a higher percentage of which are apoptotic11,12 and, following transfer to a recipient mare, IVP embryos lag 2 - 3 days behind in development and are more prone to early embryonic death.5 A positive influence of the oviduct on equine embryo development is also illustrated by the more rapid development and increased likelihood of reaching the blastocyst stage of 2 - 4 cell embryos transferred into the oviduct of a recipient mare soon after ICSI, compared to embryos maintained in vitro.12 Although it also appears that the developing embryo induces changes in oviductal epithelial cell gene and protein expression,13,14 the presence of an embryo in the oviduct does not appear to affect the mare’s subsequent ability to support pregnancy, as demonstrated by the high initial and ongoing pregnancy rates in well synchronised embryo transfer recipient mares.15 The need for coordinated interaction between the progesterone primed endometrium and the developing conceptus if pregnancy is to proceed normally is clearly illustrated by the delayed development of equine embryos transferred into the uterus of a recipient mare that ovulated 5 days after the donor.60 Indeed, it is likely that a species specific minimum period of progesterone priming is required for the endometrium to be able to both provide adequate histotrophic nutrition and become receptive for implantation.	cache/ct-9455.pdf	txt/ct-9455.txt