Effect of progestational stage of the endometrium on implantation, fetal survival and fetal size in the rabbit,Oryctolagus cuniculus
✍ Scribed by Hafez, E. S. E.
- Publisher
- John Wiley and Sons
- Year
- 1962
- Tongue
- English
- Weight
- 708 KB
- Volume
- 151
- Category
- Article
- ISSN
- 0022-104X
No coin nor oath required. For personal study only.
✦ Synopsis
The chain of interactions between the blastocyst and endometrium at implantation can be divided into three groups:
(a) surface attachment, the blastocyst is immobilized and its site is independent of the muscular contractions of the myometrium; (b) inter-cellular attachment, the zona pellucida is denuded completely or partly at the site of attachment and the trophoblastic cells can be detected within the maternal tissue; (c) intra-cellular attachment, metabolites (other than those transferred by absorption) from material origin can be exchanged with fetal cells. The histological and cytological changes at the time of implantation have been described by the early histologists and embryologists (reviewed by Boyd and Hamilton, '58).
Chang ('50) studied the development of 1-, 2-, 4-and 6-day-old embryos transferred into recipient animals on different days early in pseudopregnancy. When the development stage of the embryo and the endometrium differed by more than two days no fetuses survived to term. Similar results were reported for the mouse (Fekete and Little, '42; McLaren and Michie, '56) and rat (Dickmann and Noyes, '60; Noyes and Dickmann, '60) and sheep (Averill and Rowson, '58). Rat embryos were transferred into the uterus at various developmental stages. When the ova were the same age as or one day older than the recipient's stage of pseudopregnancy, most survived to term (Noyes and Dickmann, '60; Dickmann and Noyes, '60). One additional day of development before implantation gives the embryo a selective advantage over normally developed controls in terms of fetal weight (Noyes et al., '61b).