In vivo aging of oocytes influences the behavior of nuclei transferred to enucleated rabbit oocytes

Adenot, Pierre; Szöllösi, Maria S.; Chesné, P.; Chastant-Maillard, Sylvie; Renard, Jean‐Paul

doi:10.1002/(sici)1098-2795(199703)46:3<325::aid-mrd11>3.0.co;2-y

Cited by 37 publications

(9 citation statements)

References 41 publications

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“…These types, established according to the integrity of the first polar body (PB1) were those oocytes with a whole first polar body (w-PB1) and those with a fragmented PB1 (f-PB1). The PB1 fragmentation, and even its degeneration, is considered as an expression of in vivo ageing or over-ripeness [1,2,25,32]. With ageing, oocytes increase their sensitivity to electrical stimuli [1,4,11,22,31].…”

Section: Discussionmentioning

confidence: 99%

“…The PB1 fragmentation, and even its degeneration, is considered as an expression of in vivo ageing or over-ripeness [1,2,25,32]. With ageing, oocytes increase their sensitivity to electrical stimuli [1,4,11,22,31]. However, after applying the established variable electrical pulsing treatment to the w-PB1 and f-PB1 oocytes, we did not detect significant differences in the mean number of pulses required to initiate the haploid activation display, nor in the normal activation rates obtained.…”

Section: Discussionmentioning

confidence: 99%

“…After treatment, oocytes were selected for general healthy appearance. Two types of recovered oocytes were established according to the integrity of the first polar body (PB1): oocytes with a whole first polar body (w-PB1) and those with a fragmented PB1 (f-PB1), as a morphological sign of overripeness [1,2,32]. This initial distinction was maintained throughout the activating treatment and culture.…”

Section: Oocyte Recovery and Preparationmentioning

confidence: 99%

“…Moreover, in our experience, two types of oocytes at metaphase II were recovered from the female oviduct, at a similar post-hCG age. These types were established according to the integrity of the first polar body (PB1): oocytes with a whole first polar body (w-PB1) and those with a fragmented PB1 (f-PB1), probably as a morphological sign of over-ripeness [1,3,32].…”

Section: Introductionmentioning

confidence: 99%

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Use of a variable electrical pulsing sequence in rabbit oocyte activation

Escribá

García-Ximénez

2000

Reprod. Nutr. Dev.

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-Variability in oocyte activation sensitivity to electrical stimuli was shown in two types of oocytes (i.e., oocytes with a whole first polar body: w-PB1 and those with a fragmented PB1: f-PB1), of a similar post-ovulatory age. In order to initiate the normal activation display (i.e., extrusion of the second polar body), the w-PB1 oocytes required, on average, 3.6 ± 0.2 pulses and the f-PB1 oocytes 2.9 ± 0.1 pulses (p = 0.18). From both experimental series carried out in this work, the average haploid activation rates were 68% and 70% for w-PB1 and f-PB1 oocytes, respectively. Oocyte type did not affect the haploid embryo developmental ability observed at 24 h of culture (8-cell stage: 33-35% in Series 1 and 23-26% in Series 2), nor at 32 h of culture (16-cell stage: 77-93% and morula stage: 34-41%; Series 2). Therefore, in further experiments, the f-PB1 oocytes may also be used as potential forerunners of haploid embryos, almost up to the morula stage.rabbit / oocyte / electroactivation / haploid development / overripe Résumé -Utilisation de différentes séquences de pulsations électriques pour l'activation des ovocytes de lapine. La variabilité de la sensibilité de l'ovocyte à l'activation par stimulations élec-triques a été analysée pour deux types d'ovocytes : des ovocytes avec un premier globule polaire entier (w-PB1) ou fragmenté (f-PB1) pris au même âge post-ovulatoire. Pour accomplir la première étape d'activation (expulsion du 2 e globule polaire), les ovocytes w-PB1 ont requis en moyenne 3,6 ± 0,2 pulses et les f-PB1 2,9 ± 0,1 (p = 0,18). Les résultats des deux expériences réalisées montrent que les taux d'activation haploïde ont été en moyenne de 68 et 70 % pour les w-PB1 et les f-PB1 respectivement. Aucune différence n'a été observée selon le type d'ovocyte sur le développement parthénogénétique haploïde in vitro, soit après 24 h de culture (stade de 8 cellules : 33-35 % lors de la 1 re expérience et 23-26 % lors de la 2 e ) soit après 32 h (stade de 16 cellules : 77-93 % et stade morula : 34-41 % au cours de la 2 e expérience). Ces résultats indiquent que les ovocytes de type f-PB1 peuvent être utilisés comme des précurseurs potentiels d'embryons haploïdes au moins jusqu'au stade morula. lapin / ovocyte / électroactivation / développement haploïde / maturité Reprod. Nutr. Dev. 40 (2000) 261-269 261

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Oocyte Recovery and Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Use of a variable electrical pulsing sequence in rabbit oocyte activation

Escribá

García-Ximénez

2000

Reprod. Nutr. Dev.

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“…This showed that the aging of matured oocytes primed their intrinsic ability to undergo pronuclear formation. In nuclear transferred embryos reconstructed with aged oocytes as recipient cytoplasm, it has been reported that not only pronuclear formation and 2-cell progression but also blastocyst formation were improved [2][3][4]. Additionally, higher fertilization and pronuclear formation rates were noted in aged oocytes which were used for intracytoplasmic sperm injection [5,6].…”

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confidence: 99%

Effect of Oocyte Aging on Parthenogenetic Activation with Cycloheximide and A Iteration of the Activity of Maturation Promoting Factor during Aging of Bovine Oocytes.

2000

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This study was carried out to examine the underlying mechanism for the high susceptibility of bovine aged oocytes to activation stimulus. The oocytes were matured for 21, 27, 33, and 39 h and were then parthenogenetically activated with different concentrations of cycloheximide (CHX); their activation rates were then assessed. Additionally, the p34 cdc2 kinase activities in oocytes matured for different time periods were determined. The activation rates of oocytes treated with CHX increased with oocyte aging. In oocytes cultured for as long as 39 h in maturation medium, the treatment led to maximal activation rate of oocytes even in those with the lowest concentration of CHX. The p34 cdc2 kinase activity in oocytes decreased progressively with prolonged incubation time and the activity of the oocytes cultured for 39 h was approximately 40% of that of oocytes cultured for 21 h. In conclusion, the sensitivity of bovine oocytes to activation stimulus increases during in vitro aging; also, the time dependent decline in the capacity of oocytes to synthesize the regulatory protein required for maintaining MII stage may contribute to a high susceptibility of aged oocytes to protein synthesis inhibitor (activation stimulus). Key words: Bovine oocyte, Aged oocyte, Cycloheximide, MPF, ActivationIn a study to explore the influence of interactions between aged gametes on fertilization and early development, Smith and Lodge [1] found that pronuclear development of long-term aged ova was higher than that of short-term aged ova when fertilized by all groups of aged sperm. This showed that the aging of matured oocytes primed their intrinsic ability to undergo pronuclear formation. In nuclear transferred embryos reconstructed with aged oocytes as recipient cytoplasm, it has been reported that not only pronuclear formation and 2-cell progression but also blastocyst formation were improved [2-4]. Additionally, higher fertilization and pronuclear formation rates were noted in aged oocytes which were used for intracytoplasmic sperm injection [5,6]. These results suggest the possibility that aging of oocytes may result in increasing sensitivity to various activation stimulus treatments.Meiotic arrest of mammalian oocytes is known to be maintained by persistently high activity of maturation promoting factor (MPF). The sustained high MPF activity is maintained by cytostatic factor (CSF) activity [7]. The key component of CSF, Mos, may regulate MAPK which is activated by the MAP kinase cascade [8,9]. Inactivation of these kinases (MPF, MAPKs, and Mos) is caused by fertilization or other parthenogenetic stimuli through the oscillations of intracellular Ca 2+ , leading to release from MII arrest and pronuclear formation [10,11]. Accordingly, it is thought that much readier occurrences of activation in aged oocytes are dependent on the decline in the activities of enzymes, including MPF, MAPK, and Mos. However, the relationship between the activation of aged oocytes and the changes in their enzyme activities remains to be fully e...

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