In vitro maturation and transfer of equine oocytes after transport of ovaries at 12 or 22 °C

Preis, K.A.; Carnevale, E.M.; Silva, M.A. Coutinho da; Brienza, V. Caracciolo di; Gomes, Guilherme M.; Maclellan, L.J.; Squires, E.L.

doi:10.1016/j.theriogenology.2003.06.008

Cited by 25 publications

(7 citation statements)

References 21 publications

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“…There was no difference in pregnancy rate between oocytes recovered from the dominant preovulatory follicle 24 hr after gonadotropin administration and cultured for 12 hr before transfer and those recovered at 35 hr and cultured for 1 hr before transfer (Hinrichs et al, 2000). Similar oviductal transfer of IVM oocytes, originating from immature oocytes recovered either by transvaginal follicle aspiration ex vivo or from slaughterhouse tissue, yielded a <20% pregnancy rate (Scott et al, 2001; Preis et al, 2004), although the rate per fertilizable (MII) oocyte may be up to 100% higher in actuality because the maturation status of the oocytes at the time of transfer was unknown.…”

Section: Developmental Competencementioning

confidence: 99%

The equine oocyte: Factors affecting meiotic and developmental competence

Hinrichs

2010

Molecular Reproduction Devel

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SUMMARYThere is currently much interest in assisted reproduction techniques in the horse, however, many aspects of oocyte maturation, fertilization, and embryo development in the horse differ from those in other species. Because of the close attachment of the equine oocyte to the follicle wall, scraping of the follicle is the most effective method for oocyte recovery. A notable feature of equine oocytes is that those with expanded cumuli (Ex oocytes), which originate from atretic follicles, have higher meiotic competence (ability to mature to metaphase II in vitro) than do oocytes with compact cumuli (Cp oocytes). Cp oocytes originate in viable follicles but are largely juvenile. Recovery and culture of equine oocytes immediately after slaughter yields a higher maturation rate than that obtained from oocytes after ovary storage; this is related to damage to chromatin in Cp oocytes during storage. In contrast, developmental competence (rate of blastocyst development in vitro) is higher in oocytes recovered from the ovary after a delay. The optimum duration of maturation varies based on cumulus morphology and time of recovery from the ovary, but there is no difference in developmental competence between Ex and Cp oocytes. Because standard in vitro fertilization is not repeatable in the horse, oocyte transfer (surgical transfer of oocytes to the oviducts of inseminated mares) has been developed to allow fertilization of isolated oocytes. Fertilization in vitro may be achieved using intracytoplasmic sperm injection; culture of injected oocytes in a medium with high glucose can yield over 30% blastocyst development.Mol. Reprod. Dev. 77: 651-661,

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Section: Developmental Competencementioning

confidence: 99%

The equine oocyte: Factors affecting meiotic and developmental competence

Hinrichs

2010

Molecular Reproduction Devel

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“…A previous study reported that blastocyst rates were similar after ICSI for immature and DSF oocytes (33 and 41%, respectively; ); these authors postulated that the blastocyst rate for DSF oocytes should be much higher, as DSF oocytes yield a ≥75% pregnancy rate if transferred to the oviduct . In contrast, use of immature oocytes yields a low pregnancy rate after they are transferred to the oviduct (∼15%; ). Thus, in vitro and in vivo blastocyst production appeared to be similar for immature oocytes.…”

Section: Discussionmentioning

confidence: 95%

Effect of potential oocyte transport protocols on blastocyst rates after intracytoplasmic sperm injection in the horse

Foss

Ortis

Hinrichs

2013

Equine Veterinary Journal

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Reasons for performing study: Intracytoplasmic sperm injection (ICSI) is used to produce foals from otherwise infertile mares and from stallions with limited sperm stores, but requires expensive equipment and is technically demanding. Methods to transport oocytes to ICSI laboratories would allow collection of oocytes by the referring veterinarian and enable greater application of this technique. Objectives: This study was conducted to evaluate protocols that could be used to transport immature and maturing oocytes for ICSI. Study design: In vitro experiment. Methods: Oocytes were recovered by transvaginal ultrasound-guided follicular aspiration either from dominant follicles 24 h after deslorelin administration (dominant stimulated follicle [DSF]), or from subordinate (immature) follicles at the same time. To mimic transport, DSF oocytes were incubated overnight under differing conditions before ICSI; immature oocytes were placed in varying conditions overnight before in vitro maturation, followed by ICSI. The rate of blastocyst production was compared among treatments. Results: Blastocysts were produced in all groups. Dominant stimulated follicle oocytes held in sealed tubes in pre-equilibrated control maturation medium maintained at 37°C yielded blastocyst development equal to that obtained for control incubated oocytes (70%). Dominant stimulated follicle oocytes held similarly in a warm passive device yielded poor blastocyst development (10%). Immature oocytes held for one or 2 nights in modified M199 medium, or for one night in commercial embryo holding solution, in air at room temperature, yielded 35-37% blastocyst development per injected oocyte. Conclusions: A commercially available medium can be used for shipping immature oocytes at room temperature with good resulting blastocyst rates. Better blastocyst rates per oocyte are obtained from DSF oocytes; however, these require maintenance at 37°C and as they are already maturing at the time of collection, are more sensitive to delays. This new, practical information supporting transport of both immature and DSF oocytes for ICSI may allow wider use of this procedure.

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“…On the other hand, ovary storage at 12-20 C for 4-24 h maintains the developmental competence of equine oocytes after ICSI [24]. Pregnancies have been obtained from in vitro-matured equine oocytes derived from transported ovaries (12 or 22 C, 18-24 h) by oocyte transfer to a recipient's oviduct [7]. In the present study, we stored equine ovaries at 15 to 20 C and successfully cultured the oocytes to the blastocyst stage (25.5%).…”

Section: Discussionmentioning

confidence: 99%

“…Pregnancy rates of 15% (11/73, 12 C) and 18% (13/ 73, 22C) have been reported after transfer of equine IVM oocytes from transported ovaries (12 or 22 C, 18-24 h) into the oviducts of inseminated recipients (IVM and oocyte transfer) [7]. In the same laboratory, use of non-transported ovaries for IVM and oocyte transfer resulted in a pregnancy rate of 10% (4/40) [8].…”

mentioning

confidence: 97%

In Vitro Development of Equine Oocytes from Preserved Ovaries after Intracytoplasmic Sperm Injection

Matsukawa

Akagi

Adachi

et al. 2007

Journal of Reproduction and Development

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Abstract. In this study, we evaluated the meiotic competence of equine oocytes from ovaries preserved for one day. We also investigated fertilization, cleavage rate, developmental competence and freezability of equine embryos after intracytoplasmic sperm injection (ICSI). After collection from ovaries, the oocytes were classified into two groups comprised of those having compact cumulus layers (Cp) or those having expanded cumulus layers (Ex). Oocytes with a first polar body were subjected to fertilization by ICSI using frozen-thawed stallion spermatozoa and were then cultured in CR1aa medium. The rates of metaphase II-stage oocytes, normal fertilization and cleavage were not significantly different between the two oocyte categories (38.5, 70.0 and 48.7% for CP and 43.5, 60.0 and 58.8% for Ex, respectively). However, the blastocyst development rate of Ex was significantly (P<0.05) higher than that of Cp (25.5 vs. 7.7%). Three Cp-derived and 12 Ex-derived early blastocysts were cryopreserved using the slow cooling protocol, and all of them developed to hatching blastocysts after thawing. These results suggest that equine oocytes fertilized by ICSI can develop to the preimplantation stage in culture conditions similar to those used in the bovine. Furthermore, the Ex oocytes had higher developmental competence than the Cp oocytes, and the in vitro-produced blastocysts had high viability after freezing and thawing.

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In vitro maturation and transfer of equine oocytes after transport of ovaries at 12 or 22 °C

Cited by 25 publications

References 21 publications

The equine oocyte: Factors affecting meiotic and developmental competence

The equine oocyte: Factors affecting meiotic and developmental competence

Effect of potential oocyte transport protocols on blastocyst rates after intracytoplasmic sperm injection in the horse

In Vitro Development of Equine Oocytes from Preserved Ovaries after Intracytoplasmic Sperm Injection

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