The structure and function of the equine capsule in relation to embryo manipulation and transfer

Betteridge, K.

doi:10.1111/j.2042-3306.1989.tb04690.x

Cited by 79 publications

(27 citation statements)

References 36 publications

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“…In ruminants, a comparable up-regulation takes place just before trophoblast interdigitation with the endometrium [35] and, while some imprinted genes are expressed earlier in development in ruminants and pigs (namely the blastocyst stage), monoallelic expression doesn't occur until the time of trophoblast apposition and adhesion to the endometrial epithelium [35,37,38]. Although we didn't investigate the precise timing, by analogy to other species we speculate that monoallelic expression of imprinted genes in equine yolk-sac membrane is delayed until implantation is initiated by the disintegration of the embryonic capsule (days 21e23 of pregnancy) [29,39]. Certainly, by day 33, imprinted genes display a parent-oforigin monoallelic expression in equine trophoblast [23].…”

Section: Discussionmentioning

confidence: 99%

Negative uterine asynchrony retards early equine conceptus development and upregulation of placental imprinted genes

2017

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Section: Discussionmentioning

confidence: 99%

Negative uterine asynchrony retards early equine conceptus development and upregulation of placental imprinted genes

2017

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“…Embryonic damage in all likelihood occurred at the two points in the flushing system that provided the greatest impediment to the passage of the embryo; namely, the entry/exit holes in the flushing catheter and the internal diameter of the entry port into the embryo filter. Although this small percentage of embryos did suffer damage, the fact that so many passed unscathed through the narrow openings is a testament to the protective strength provided by the glycoprotein equine capsule (Betteridge 1989, Oriol et al 1993a, 1993b). This is not surprising when one considers that the embryo is subjected to strong myometrial contractions during its movement throughout the uterus between days 6 and 17 after ovulation (Ginther 1983b, Allen & Bracher 1992 to the extent that the day 13 or 14 embryo may undergo periodic compressions every 5-14 s with the resilience and elasticity of the capsule allowing temporary distortion of the spherical embryonic yolk sac (Ginther 1985).…”

Section: Discussionmentioning

confidence: 99%

Successful transfer of day 10 horse embryos: influence of donor–recipient asynchrony on embryo development

Wilsher

Clutton-Brock²,

Allen³

2010

Reproduction

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A total of 78 day 10 horse embryos were transferred non-surgically to recipient mares that had ovulated 9, 7, 6, 5, 4, 3, 2 or 1 day after (negative asynchrony), on the same day (synchronous), or 2 or 4 days before (positive asynchrony) the donor (nZ6 or 8 mares per group). Pregnancy rates between 100% (6/6) and 63% (5/8) were seen in recipient mares that were between C2 and K6 days asynchronous. Embryo survival to the heartbeat stage declined in recipients that were K7 days asynchronous and no embryos survived in recipients that were K9 days asynchronous. Irrespective of uterine asynchrony, cessation of embryo mobility and fixation at the base of a uterine horn occurred when the conceptus was w17 days old. Conceptus growth and development was slowed when embryos were placed in negatively asynchronous uteri. At the greatest degree of negative asynchrony at which embryos survived to the heartbeat stage, i.e. K7 and K6 days, development of the embryo proper and allantois was retarded. Luteostasis was achieved in recipient mares when day 10 embryos were transferred to recipient mares at any stage of asynchrony between K9 and C2 days with respect to the donor. These results indicate that in the horse, there is a wide window for establishment of pregnancy following embryo transfer to asynchronous recipients. Although progesterone priming of the uterus to a stage equivalent to that of the transferred embryo does not appear to be a prerequisite for embryo survival, it does nonetheless influence embryonic development.Reproduction (2010) 139 575-585

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“…Equids stand out among the large domestic animal species by having an embryo that takes as long as 6 days to traverse the oviduct and enter the uterus (Battut et al 1997), a conceptus that remains spherical due to its envelopment by a tough glycoprotein capsule between days 6.5 and 23 after ovulation (Betteridge 1989, Oriol et al 1993a, 1993b) and a conceptus that propels itself continually throughout the uterine lumen between days 6 and 17 after ovulation (Ginther 1983a) by means of its own release of prostaglandins F 2 a and E 2 (Stout & Allen 2001). Subsequently, a discrete, annulate band of specialized invasive trophoblast cells forms the chorionic girdle that peels off the fetal membranes at around day 36 and adheres to the overlying endometrium, thereby enabling the binucleate trophoblast cells to vigorously invade the endometrium (Allen et al 1973, Stewart et al 1995.…”

Section: Introductionmentioning

confidence: 99%

Uterine influences on embryogenesis and early placentation in the horse revealed by transfer of day 10 embryos to day 3 recipient mares

Wilsher¹,

Allen²

2009

Reproduction

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Eight day 10 horse embryos were transferred non-surgically to recipient mares that had ovulated 7 days after the donors. The embryonic vesicle was seen ultrasonographically in all eight recipients, and three out of eight (38%) of the vesicles developed an embryo proper with a beating heart. Conceptus expansion was initially slower than that in control mares but continued until day 22 (recipient day 15). Time of fixation of the vesicle was related to its diameter, rather than uterine stage. Although the embryo proper first appeared ultrasonographically on day 22, as normal, it grew more slowly and the allantois expanded more slowly than that in control mares with normal pregnancies. The development of endometrial cups and their secretion of equine chorionic gonadotropin in the two mares allowed to remain pregnant to O50 days occurred at a conceptus age w7 days later than that in the control mares. The results demonstrated the uniqueness of the horse conceptus in being able to overcome a 7-day asynchrony with the uterus, and also highlighted the overriding influence of the uterine environment on conceptus development in the mare.

show abstract

The structure and function of the equine capsule in relation to embryo manipulation and transfer

Cited by 79 publications

References 36 publications

Negative uterine asynchrony retards early equine conceptus development and upregulation of placental imprinted genes

Negative uterine asynchrony retards early equine conceptus development and upregulation of placental imprinted genes

Successful transfer of day 10 horse embryos: influence of donor–recipient asynchrony on embryo development

Uterine influences on embryogenesis and early placentation in the horse revealed by transfer of day 10 embryos to day 3 recipient mares

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