Developmental Potential of Single Blastomeres of the Rabbit Egg

Abstract

Single blastomeres of two-, four-or eight-cell rabbit eggs devoid of the zona pellucida, enclosed in their own zona, or injected into an evacuated host zona were transferred to the Fallopian tubes of recipient does.No single blastomeres devoid of the zona survived, while 30% 19% and 11% of those of two-, four-and eight-cell eggs enclosed in their own zona developed into normal viable young.Thirty-three out of ninety-seven single blastomeres of four-cell eggs injected into host zonae showed limited development, undergoing one or more cleavages, during the first 2 days after transfer. However, none implanted or developed into 6-day blastocysts. Failure to survive may have been due to leucocytic invasion of the zona and subsequent destruction of the blastomeres.The developmental potential of individual blastomeres is briefly discussed in relation to the production of identical offspring.

Effects of strain and embryo transfer model (embryos from one versus two donor does/recipient) on results of cryopreservation in rabbit

“…The application of morphological criteria to screen rabbit embryos after thawing is important, given that rabbit embryos without zona pellucida and mucin coat fail to develop after transfer (Moore et al, 1968;Rottmann and Lampeter, 1981 ). Our percentages of normal embryos after thawing in SY and NZ strains agree with those obtained in rabbits by previous authors (Tsunoda et al, 1982;Kojima et al, 1985Kojima et al, , 1987Garcfa-Xim6nez and Vicente, 1991) Comparing the 2 models of embryo transfer, it was observed that the single transfer has the risk that only 1 foetus might develop.…”

Attempts to Produce Identical Offspring in the Sheep by Mechanical Division of the Ovum

“…It has been shown that single blastomeres of early-cleavage-stage ova of the mouse, rat, rabbit and pig are capable of continued cleavage (Nicholas and Hall 1942;Seidel 1952;Tarkowski 1959aTarkowski , 1959bTarkowski and Wr6blewska 1967;Moore et al 1968Moore et al , 1969 and single blastomeres of two-, four-and eight-cell rabbit ova have developed into apparently normal young following transfer to recipient does (Seidel 1952;Moore et al 1968). Similar results have been achieved in sheep (Moore, unpublished data).…”

“…Moore et al (1969) suggested that each of the blastomeres of these early-cleavage-stage ova may well possess the potential for full development, thus raising the possibility of artificially producing identical offspring. However, attempts at producing identicals in the rabbit and pig failed (Moore et al 1968(Moore et al , 1969.…”

Intraperitoneal Insemination in the Rabbit

“…The unexpec¬ ted failure to recover eggs which should have been present in the tubes is thought to be due to their early destruction by excess spermatozoa, as previ¬ ously suggested by Noyes, Adams & Walton (1959). If (Moore, Adams & Rowson, 1968). Thus, the detrimen¬ tal effect of excess spermatozoa appears to lie primarily in disrupting the integrity of the zona pellucida, which in the rabbit does not in any case afford a block to polyspermy.…”