In vitro and in vivo developmental capacity of oocytes from prepubertal and adult sheep

O’Brien, Justine K.; Catt, S.L.; Ireland, Kirsty; Maxwell, W.M.C.; Evans, G.

doi:10.1016/s0093-691x(97)00134-9

Cited by 90 publications

(63 citation statements)

References 35 publications

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“…Although oocytes obtained from prepubertal animals have produced viable offspring after in vitro maturation and IVF (Revel et al 1995, O'Brien et al 1997, Khatir et al 1998a, Ptak et al 1999, the developmental competence of these embryos was lower than that of embryos produced from adult animals (Seidel et al 1971, Pinkert et al 1989, Revel et al 1995, Damiani et al 1996, Khatir et al 1996, O'Brien et al 1996, Ledda et al 1997, Izquierdo et al 1999, Wu et al 2007. In vitro matured oocytes of prepubertal bovine showed abnormal chromatin microtubule configurations and protein synthesis (Damiani et al 1996, Gandolfi et al 1998, Khatir et al 1998b).…”

Section: Introductionmentioning

confidence: 99%

Effects of puberty and gonadotropins on the molecular events controlling meiotic resumption of mouse oocytes

Han¹,

Cao²,

Wang³

et al. 2010

Reproduction

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Although studies suggest that the low competence of oocytes from prepubertal animals is due to their insufficient cytoplasmic maturation and that FSH improves oocyte maturation possibly by retarding meiotic progression and allowing more time for cytoplasmic maturation, the mechanisms by which puberty and gonadotropins regulate meiotic progression require additional detailed studies. For the first time, we observed that while meiotic progression was significantly slower, the maturation-promoting factor (MPF) activity of oocytes was significantly higher in prepubertal than in adult mice. To resolve this contradiction, we specified the molecules regulating the MPF activity and their localization during oocyte maturation in prepubertal and adult mice primed with or without gonadotropins. Our tests using corresponding enzyme regulators suggested that while activities of protein kinase A were unaffected, the activity of adenylate cyclase (ADCY) and phosphodiesterase increased while cell division cycle 2 homolog A (CDC2A) decreased significantly after puberty. While most of the adult oocytes had CDC2A protein concentrated in the germinal vesicle (GV) region, the majority of prepubertal oocytes showed no nuclear concentration of CDC2A. Maximally priming mice with equine chorionic gonadotropin brought the above parameters of prepubertal oocytes close to those in adult oocytes. Together, the results suggest that puberty and gonadotropin control oocyte meiotic progression mainly by regulating the ADCY activity and the concentration of the activated MPF toward the GV region.

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Section: Introductionmentioning

confidence: 99%

Effects of puberty and gonadotropins on the molecular events controlling meiotic resumption of mouse oocytes

Han¹,

Cao²,

Wang³

et al. 2010

Reproduction

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“…Although we have not added EGF to IVM medium our results were similar to these researchers. O'Brien et al (1997) found that the blastocyst rates of the oocyte collected from pubertal sheeps were significantly higher than those collected from prepubertal sheeps (34%-15%). However, in the same study pregnancy rates were not significantly different between two groups (30% vs. 40%).…”

Section: Discussionmentioning

confidence: 83%

“…The presence of the EGF and IGF receptors on granulosa cells are the evidence that they are effective on IVM. It is stated that IGF shows synergetic action with FSH and they stimulates the steroid production and oocyte maturation (O'Brien et al, 1997). Grazul-Bilska et al (2006) found that adding EGF to medium could increase the cleavage rates of sheep embryos than the control group (59% vs. 78%).…”

Section: Discussionmentioning

confidence: 99%

Effect of Different Cooling Rates on Embryo Survivability and Pregnancy Rates in Freezing Sheep Embryos

Öztürk¹,

Demır²,

Arıcı³

et al. 2016

İstanbul Üniv. Vet. Fak. Derg.

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In the first stage of the study, oocytes obtained from ovaries from abbatoir (n=2990) were incubated in maturation medium for 24 h. The maturated oocytes were left for in vitro fertilization (IVF) for 20 hours. The cleavaged embryos (n=1305) were left for in vitro culture (IVC) for six days. Then morula-blastocyst stage embryos divided randomly in three groups (Grup I: 0.5°C/min, Grup II: 0.8°C/min, Grup III: 1°C/min). Embryos in each group (n=50) were frozen at different cooling rates in 1.5 M ethylene glycol containing freezing medium. As a result, 0.5°C/min cooling rate group was found as the most successful group (P<0.05). In the second stage of the study, in vivo embryos (morula-blastocyst) derived from donor sheep were frozen at 0.5 °C/min. Frozenthawed nineteen embryos were transferred to hormonally pretreated seventeen recipients. At the 60 th day of the transfer, three recipients were diagnosed as pregnant and one of them had twins. One of the three recipients gave birth and two sheeps had early embryonic loss are observed in the later ultrasound scanning. In the study, 0.5°C/min cooling rate in the slow freezing of sheep embryos was found out to be more successful cooling rates and pregnancy following a healthy lambing is achieved. Özet Koyun Embriyolarının Dondurulmasında Farklı Soğutma Hızlarının Embriyoların Canlılığı ve Gebelik Oranları Üzerindeki EtkisiÇalışmanın ilk bölümünde, mezbahadan sağlanan ovaryumlardan kazanılan oositler (n=2990) olgunlaştırma medyumu içerisinde 24 saat süreyle olgunlaştırıldı. Ardından, 20 saat süreyle İn Vitro Fertilizasyona (İVF) bırakıldılar. Yarıklanma gösteren embriyolar (n=1305), Sentetik Ovidukt Fluid (SOF) medyumu içerisine alınarak altı gün süresince İn Vitro Kültüre (İVK) bırakıldılar. İVK sonrası elde edilen morula-blastosist aşamasındaki embriyolar rastlantısal şekilde üç farklı dondurma hızı grubuna eşit olarak ayrıldılar (Grup I: 0,5 °C /dk, Grup II: 0,8 °C /dk, Grup III: 1 °C /dk). Her bir gruptaki embriyolar (n=50), 1,5 M etilen glikol bulunan dondurma medyumu içerisinde farklı soğutma hızlarında donduruldu. Sonuçta 0,5 °C/dk soğutma hızının en başarılı grup olduğu belirlendi (P<0,05). Çalışmanın ikinci bölümünde, verici koyunlardan elde edilen in vivo embriyolar (Morula-Blastosist) çalışmanın birinci bölümünde bulunan en başarılı soğutma hızı (0,5 °C/dk) ile soğutularak donduruldu. Dondurulan 19 adet embriyo hormonel olarak hazırlanmış 17 alıcı koyuna transfer edildi. Transfer sonrası 60. günde yapılan ultrason muayenesinde üç adet koyunda gebeliklere ait embriyonik keseler gözlendi ve bu koyunlardan birinde de ikiz gebelik saptandı. Gebe koyunlardan bir tanesinde doğum gerçekleşti; diğer iki koyunda ise ileriki dönemde yapılan ultrason muayenesinde gebeliklerin sonlandığı gözlendi. Çalışma sonucunda, koyun embriyolarının dondurulması sırasında 0,5°C/dk soğutma hızının en başarılı hız olduğu ve bu yöntemle dondurulan embriyoların transferinden de gebelik elde edilebildiği saptandı.

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“…Sheep ovum pick-up systems are applied in living animals using minimal invasive procedures such as laparoscopic ovum pick-up (LOPU) technique guided by laparoscopy [113][114][115]. As referred before, these procedures when used in vivo are usually associated with follicular stimulation treatments [116] to raise the number of collected COCs [117], allowing better maturation, fertilization, and in vitro development capacities [101,118]. Moreover, the development of these in vivo techniques of oocyte collection is important, as abattoir-derived oocytes usually cannot be used in genetic programs because of their unknown sanitary and even genetic status, being applied mainly for research proposes [115].…”

Section: Collection Of Oocytesmentioning

confidence: 99%

“…This quality depends on the competence of the oocyte to complete meiosis, which is affected by the follicle size [35]. It is also clearly established that prepubertal oocytes do not have the developmental potential of those collected from adult ewes [118], although, in the future, the results obtained with juvenile oocyte collection could have potential interest for decreasing half the generation interval in genetic programs [112].…”

Section: Collection Of Oocytesmentioning

confidence: 99%

Cryopreservation of Sheep Produced Embryos – Current and Future Perspectives

Romão¹,

Marques²,

Bettencourt³

et al. 2016

Insights From Animal Reproduction

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Due to economical and scientific limitations, sheep embryo reproductive technologies are less commercially applied than in other animal species. However, it is very clear that, in the near future, those techniques are expected to have a central role in animal production as a consequence of genetic and reproductive demands. One drawback is that results obtained after sheep embryo cryopreservation are unattractive for commercial purposes. It is expected that a successful cryopreservation of sheep embryos can push forward all other reproductive biotechnologies in this species, such as multiple ovulation and embryo transfer (MOET), artificial insemination, or in vitro production of embryos. This paper tries to discuss the current and future perspectives of cryopreservation of in vivo-and in vitro-produced sheep embryos concerning advantages and limitations for its practical use and possible solutions for improving methods to allow a higher survival rate of cryopreserved embryos.

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In vitro and in vivo developmental capacity of oocytes from prepubertal and adult sheep

Cited by 90 publications

References 35 publications

Effects of puberty and gonadotropins on the molecular events controlling meiotic resumption of mouse oocytes

Effects of puberty and gonadotropins on the molecular events controlling meiotic resumption of mouse oocytes

Effect of Different Cooling Rates on Embryo Survivability and Pregnancy Rates in Freezing Sheep Embryos

Cryopreservation of Sheep Produced Embryos – Current and Future Perspectives

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