The Survival of Single Blastomeres of Pig Eggs Transferred to Recipient Gilts

Moore, N. W.; Polge, C.; Rowson, Lea

doi:10.1071/bi9690979

Cited by 35 publications

(9 citation statements)

References 9 publications

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“…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 Similar results have been achieved in sheep (Moore, unpublished data).…”

Section: Introductionsupporting

confidence: 71%

“…Naked blastomeres were rapidly destroyed. 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.…”

Section: Introductionmentioning

confidence: 99%

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

Trounson¹,

Nw²

1974

Aust. Jnl. Of Bio. Sci.

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In an attempt to produce identical offspring artificially, the inner cell mass of ova, collected on days 4, 6 and 7 after oestrus (day 0 = day of oestrus), was mechanically divided into two equal sections.The sections were then either cultured in vitro for 2 days and the resulting apparently normal blastocysts transferred to recipient ewes or, in the case of day-7 ova, transferred to recipient ewes without a period of in vitro culture.Half sections of day-4 ova showed little further development in culture and in most the individual cells separated and dispersed. Those of day 6 and 7 showed no dispersion and 24 apparently normal blastocysts were recovered following the culture of 82 half sections. Fourteen of the normal blastocysts developed from each of both half sections of seven day-6 ova.Nineteen normal blastocysts were transferred individually to recipients following culture, but only two developed into lambs and both lambs developed from blastocysts of different ova. A further 18 half sections of day-7 ova were transferred without an intervening period of culture but none developed into lambs.Although a substantial proportion of the half sections of day-6 and day-7 ova showed apparently normal development in culture, very few showed continued normal development in recipients. It is suggested that cellular specialization within the inner cell mass may have occurred before the inner cell mass was divided.

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Section: Introductionsupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

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

Trounson¹,

Nw²

1974

Aust. Jnl. Of Bio. Sci.

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“…Experimentally, blastomeres isolated from early cleavage-stage embryos and transferred to an empty zona pellucida prepared from another ovum are capable of developing to the blastocyst stage in vitro. However, transfer of these micromanipulated embryos to the oviduct or uterus has been reported to result in impaired development or embryonic loss [8][9][10]. Possible causes for these results include attacks on inner blastomeres by immune cells that enter through the hole made in the zona pellucida for blastomere transfer and the inability of embryos with holes in the zona pellucida to withstand the physical pressure associated with passage through the oviduct [8][9][10].…”

mentioning

confidence: 99%

“…It is thought to be responsible for preventing the loss of blastomeres from the early embryo within the oviduct and the adhesion of blastomeres to oviductal epithelial cells [7]. Damage to the zona pellucida of early cleavage-stage embryos is known to exert adverse effects on the development and survival of embryos in the reproductive tract [8,9]. Experimentally, blastomeres isolated from early cleavage-stage embryos and transferred to an empty zona pellucida prepared from another ovum are capable of developing to the blastocyst stage in vitro.…”

mentioning

confidence: 99%

Association Between Embryonic Loss and Damage to the Zona Pellucida by Invasive Micromanipulation During Oviductal Transfer of Early-Stage Embryos in Pigs

Ueno

Kurome

Tomii

et al. 2007

Journal of Reproduction and Development

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Abstract. The aim of this study was to examine the impact of zona pellucida damage, which might arise during somatic cell nuclear transfer (SCNT), on the development and survival of transferred embryos. The zonae pellucidae of in vitro matured oocytes were either punctured with 8-to 10-µm square-ended nuclear injection pipettes and piezo pulses or slit with 35-to 40-µm enucleation pipettes. Intact oocytes were used as controls. These oocytes were electroactivated to induce parthenogenesis and transferred to the oviducts of estrus-synchronized recipient gilts. After 5 to 7 days, the recipient uteri were flushed to collect embryos, and embryonic development (morula-blastocyst stage embryos/collected embryos) and survival (viable embryos/collected embryos) were determined. In total, 221 zona-punctured, 129 zona-slitted and 57 intact embryos were transplanted into four, two and two gilts, respectively. The efficiency of embryo recovery was similar in all groups (64.3 to 79.1%). However, the zona-penetrated and incised embryos exhibited unstable development and survival compared with the controls; development and survival of the control embryos were 94.7 and 87.7%, whereas those of the zona-punctured embryos were 69.0 and 47.9% (P<0.01) and those of the zona-slit embryos were 64.7 and 50.0% (P<0.01). Cells with large foci that appeared to be macrophage giant cells were observed at the surface or inside the degenerated zona-damaged embryos. These results indicate that the recipient's immune response to damage to the zona pellucida may impair embryonic development after transplantation to the oviduct. This may be one of the factors causing the reduced efficiency of live progeny production by SCNT.

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“…In the mouse, rat, rabbit and pig, a relatively intact zona is essential for the continued development in vivo of recently fertilized eggs (Nicholas & Hall, 1942;Seidel, 1952Seidel, , 1956Seidel, , 1960Tarkowski, 1959;Moore, Adams & Rowson, 1968;Moore, Polge & Rowson, 1969). Blastocysts and eight-cell eggs of the rat and mouse, from which the zonae have been completely removed, will show continued development in vitro, but on transfer to recipients only blastocysts show continued development (Bronson & McLaren, 1970;Modlinski, 1970;Brun & Psychoyos, 1972).…”

Section: Introductionmentioning

confidence: 99%

The Survival and Development of Sheep Eggs Following Complete or Partial Removal of the Zona Pellucida

Trounson¹,

Moore²

1974

Reproduction

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Summary. The effect of`Protease' on the zona pellucida of fertilized and unfertilized sheep eggs was examined, and the effects ofthe treatment and of mechanical removal of part of the zona on the subsequent development of fertilized eggs was assessed in vitro and in vivo.The zonae of follicular eggs were digested by`P rotease' within 25 min of exposure. In ovulated eggs, the resistance of the zona to digestion decreased with age. Zonae of eggs collected 2 days after oestrus (Day 2) were extremely resistant whereas nearly all the Day-5 eggs lost their zonae within 10 min. Fertilization had little effect upon the susceptibility of zonae to digestion by`P rotease'.Neither age of egg nor method of treating the zona had any effect on subsequent development of fertilized Day-2 and Day-6 eggs in culture, but there were effects of both factors on the proportion of eggs which developed to normal Day-25 embryos.`P rotease' treatment of Day-2 and Day-3 eggs failed to digest the zona completely and a high proportion of such eggs developed to normal embryos whereas only a few eggs of similar age, in which part of the zona was removed mechanically, developed normally. The zonae of Day-4 to Day-6 eggs were invariably removed by`P rotease' and the method of treatment had no effect on the proportion of eggs which developed to normal embryos. Irrespective of method of treatment, more Day-6 than Day-4 eggs developed to normal embryos. Culture for 2 days following treatment did not increase the survival of Day-6 eggs when they were transferred to recipients. Ovulation and ageing of eggs appear to be associated with changes in the zona pellucida which influence its susceptibility to digestion by proteolytic enzymes. In early cleavage stage eggs, the major r\l=o^\leof the zona may be protection of the inner cell mass from the uterine environment.

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The Survival of Single Blastomeres of Pig Eggs Transferred to Recipient Gilts

Cited by 35 publications

References 9 publications

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

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

Association Between Embryonic Loss and Damage to the Zona Pellucida by Invasive Micromanipulation During Oviductal Transfer of Early-Stage Embryos in Pigs

The Survival and Development of Sheep Eggs Following Complete or Partial Removal of the Zona Pellucida

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