Factors affecting developmental competence of equine oocytes after intracytoplasmic sperm injection

Choi, Young-Ho; Love, L.B.; Varner, D.D.; Hinrichs, Katrin

doi:10.1530/rep.1.00087

Cited by 31 publications

(21 citation statements)

References 38 publications

(49 reference statements)

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“…We previously found high cleavage rates (69-94%) in equine zygotes cultured in the semidefined medium CZB-C ϩ BSA, with either low or high concentrations of glucose [9]. The average nucleus number at 96 h in that medium was also good, at 6.6-12.…”

Section: Discussionmentioning

confidence: 89%

“…Several laboratories have investigated the use of synthetic oviductal fluid (SOF)-based media, including commercial G1/G2 media, for equine embryo culture. We found that a modified Chatot, Ziomek, Bavister (CZB) medium (CZB-C) was capable of supporting equine embryo development in vitro for 4 days [8] and that glucose concentration in this medium (0.55 or 5.5 mM) did not affect development at 4 days [9], but embryos were not cultured further. Culture of injected oocytes for 7 days in G1.2/G2.2 yielded up to 9% blastocyst formation [3]; no difference was seen between change of medium at 3 or 4 days.…”

Section: Introductionmentioning

confidence: 99%

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Blastocyst Formation Rates In Vivo and In Vitro of In Vitro-Matured Equine Oocytes Fertilized by Intracytoplasmic Sperm Injection1

Choi¹,

Roasa²,

Love³

et al. 2004

Biology of Reproduction

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This study was conducted to evaluate in vivo and in vitro development of in vitro-matured equine oocytes fertilized by intracytoplasmic sperm injection. Oocytes were collected from slaughterhouse-derived ovaries, matured in vitro, and injected with frozen-thawed stallion sperm. In vivo development was assessed after transfer of injected oocytes to the oviducts of recipient mares. Mares were killed 7.5-8.5 days after transfer and the uterus and oviducts flushed for embryo recovery. Of 132 injected oocytes transferred, 69 (52%) were recovered; of these, 25 (36%) were blastocysts with a blastocoele and capsule. In vitro development was assessed in three culture systems. Culture of zygotes in modified Chatot, Ziomek, Bavister medium with BSA containing either 5.5 mM glucose for 7.5 days or 0.55 mM glucose for 3 days, followed by 3 mM glucose for 2 days, then 4.3 mM glucose for 2.5 days, did not result in blastocyst formation. Culture of zygotes in Dulbecco modified Eagle medium (DMEM)/F-12 with 10% fetal bovine serum with and without coculture with equine oviductal epithelial explants yielded 16% and 15% blastocyst development, respectively. Development to blastocyst was significantly lower in G1.3/2.3/BSA than in DMEM/F-12/BSA or in either medium with 10% added serum (2% vs. 18%, 18% or 20%; P < 0.05), suggesting that requirements for equine embryo development differ from those for other species. These results indicate that in vitro-matured equine oocytes are sufficiently competent to form 36% blastocysts in an optimal environment (in vivo). While we identified an in vitro culture system that provided repeatable blastocyst development without coculture, this yielded only half the rate of development achieved in vivo.

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Section: Discussionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Blastocyst Formation Rates In Vivo and In Vitro of In Vitro-Matured Equine Oocytes Fertilized by Intracytoplasmic Sperm Injection1

Choi¹,

Roasa²,

Love³

et al. 2004

Biology of Reproduction

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“…The optimum duration of oocyte maturation for developmental competence has not been defined in the horse, and may vary according to oocyte cumulus type: we found that cleavage rates at 48-96 h after ICSI varied differentially with maturation duration for Ex and Cp oocytes [38]. Information is not available on the effects of ovary storage, cumulus type, or duration of oocyte maturation on blastocyst development in horses.…”

Section: Introductionmentioning

confidence: 84%

Chromatin Configuration Within the Germinal Vesicle of Horse Oocytes: Changes Post Mortem and Relationship to Meiotic and Developmental Competence1

Hinrichs

Choi

Love

et al. 2005

Biology of Reproduction

133

129

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We evaluated the relationship of initial chromatin configuration to time of oocyte recovery and to nuclear maturation after culture in horse oocytes having compact (Cp) and expanded (Ex) cumuli. In addition, we evaluated the effect of oocyte type, time of recovery, and duration of culture on blastocyst development after intracytoplasmic sperm injection. In oocytes collected within 1 h of slaughter, fibrillar and intermediate chromatin configurations were more prevalent in Cp than in Ex oocytes (68% and 12%, respectively). In Cp oocytes collected after a 5- to 9-h delay, the proportions in the fibrillar and intermediate configurations decreased significantly, and the proportions of degenerating and homogeneously fluorescent configurations increased. When cultured, 20% of oocytes classified as having fibrillar chromatin resumed meiosis, whereas 82% of intermediate and 81% to 86% of condensed chromatin oocytes did so. Meiotic resumption was higher in oocytes recovered immediately after slaughter, but these oocytes took longer to mature. Duration of maturation significantly affected blastocyst development rates in Cp oocytes recovered after a delay (13% and 38% for oocytes matured 24 and 36 h, respectively). Oocytes recovered after a delay had higher blastocyst development rates than did those collected immediately after slaughter. We conclude that the fibrillar and intermediate chromatin configurations may degenerate during ovary storage, resulting in decreased maturation rates, especially of Cp oocytes. Time of oocyte recovery and duration of maturation significantly affect the rate of blastocyst development. Oocytes with Cp and Ex cumuli have similar developmental competence to the blastocyst stage.

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“…Briefly, after maturation, oocytes were denuded of cumulus by pipetting in 0.05% hyaluronidase and those with a polar body were used for ICSI. For ICSI with frozen-thawed (control) sperm, a swim-up procedure was used (Choi et al 2004). Briefly, semen was thawed at 37 8C for 30 s and 200 ml were layered under 1 ml Sp-CZB for swim-up.…”

Section: Icsimentioning

confidence: 99%

“…The basic techniques necessary to study this, including ICSI (Choi et al 2004) and in vitro embryo culture (Hinrichs et al 2005), are currently in place. Methods for activation of horse oocytes have been investigated; notably, these include injection of cytosolic extract, prepared from sperm via multiple cycles of flash freezing and thawing.…”

Section: Introductionmentioning

confidence: 99%

Production of live foals via intracytoplasmic injection of lyophilized sperm and sperm extract in the horse

Choi

Varner²,

Love³

et al. 2011

Reproduction

Self Cite

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Work with lyophilized sperm helps delineate the factors required for successful fertilization. We investigated the use of lyophilized sperm in equine embryo production. In Experiment 1, sperm DNA fragmentation index was not affected by three freeze/thaw or lyophilization cycles. In Experiment 2, oocytes injected with lyophilized sperm or with sperm from a treatment in which lyophilized sperm were suspended in sperm cytoplasmic extract (SE) yielded blastocyst development rates of 0 and 28% respectively (P!0.05). In Experiment 3, blastocyst development rate was 6-11% after injection of sperm lyophilized from fresh or frozen-thawed semen, suspended in SE. In Experiment 4, sperm lyophilized 3.5 months or 1 week previously, suspended in SE, yielded similar blastocyst rates (6 and 3% respectively). Rates of normal pregnancy after transfer were 7/10 and 5/7 for embryos from control and lyophilized sperm treatments respectively. Three pregnancies from the lyophilized sperm treatments were not terminated, resulting in two healthy foals. Parentage testing determined that one foal originated from the lyophilized sperm; the other was the offspring of the stallion providing the sperm extract. Further testing indicated that two of five additional embryos in the lyophilized sperm treatment originated from the stallion providing the sperm extract. We conclude that both lyophilized stallion sperm and stallion sperm processed by multiple unprotected freeze-thaw cycles (as for sperm extract) can support production of viable foals. To the best of our knowledge, this is the first report on production of live offspring by fertilization with lyophilized sperm in a non-laboratory animal species.

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Factors affecting developmental competence of equine oocytes after intracytoplasmic sperm injection

Cited by 31 publications

References 38 publications

Blastocyst Formation Rates In Vivo and In Vitro of In Vitro-Matured Equine Oocytes Fertilized by Intracytoplasmic Sperm Injection1

Blastocyst Formation Rates In Vivo and In Vitro of In Vitro-Matured Equine Oocytes Fertilized by Intracytoplasmic Sperm Injection1

Chromatin Configuration Within the Germinal Vesicle of Horse Oocytes: Changes Post Mortem and Relationship to Meiotic and Developmental Competence1

Production of live foals via intracytoplasmic injection of lyophilized sperm and sperm extract in the horse

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