Induction of reversible meiosis arrest of bovine oocytes using a two-step procedure under defined and nondefined conditions

Silva, I. Oliveira e; Vasconcelos, Rosângela Batista de; Caetano, João V.O.; Gulart, L. V. M.; Camargo, L. S. A.; Báo, Sônia Nair; Silva, A.A.M. Rosa e

doi:10.1016/j.theriogenology.2010.11.021

Cited by 12 publications

(11 citation statements)

References 35 publications

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“…Oocytes isolated from follicles are cultured for a while in a maturation medium with addition of meiosis regulators, mainly, inhibitors of cdk-kinases, capable of blocking the transition from diplotenes to metaphase I, and then during the absence of these substances. Nevertheless, the obtained results are quite contradictory and suggest the need to search for specific molecules for oocyte stimulation during blocking of meiosis [11][12][13][14][15].…”

Section: Development Sex Steroid Hormonesmentioning

confidence: 99%

Bovine Oocyte Ability to Embryonic Development When Maturing in Different Two-Phase Culture Systems

Сингина¹

2017

S-h. biol.

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Section: Development Sex Steroid Hormonesmentioning

confidence: 99%

Bovine Oocyte Ability to Embryonic Development When Maturing in Different Two-Phase Culture Systems

Сингина¹

2017

S-h. biol.

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“…T 071–01) supplemented with 2.1 mg of sodium bicarbonate/mL, 75 μg of penicillin G/mL, 75 μg of streptomycin/mL and 5 % human serum albumin, in the absence and/or presence of metformin (M 5 −10 ) for 12, 24, 36, and 48 h. The concentration of metformin (M 5 −10 ) was assigned based on the results of Lee et al but not different concentration, because they have demonstrated that different concentrations of metformin alone does not affect the in vitro maturation of oocyte [ 8 ]. One of the subgroups of oocytes was stained with an aceto-orcein (1 %) solution to define nuclear maturation as the assortment of GV, GVBD, metaphase I (MI), anaphase-telophase (A-T), and MII, and as degenerated and non-detectable by using a light microscope [ 13 , 14 ]. Cultured denuded oocytes were placed in the center of glass slide, covered and compressed gently with a cover slid which attached to the glass slid by a paraffin-vaseline wax bar on each corner of cover slid to hold and fixed them in acid acetic and methanol (1:3, v/v) for 24 h. Oocytes were stained with 1 % fresh aceto-orcein (1 % orcein in 45 % glacial acetic acid) by pushing aceto-orcein solution between glass slid and cover slid using insulin syringe, and immediately observed by light microscope.…”

Section: Methodsmentioning

confidence: 99%

Does metformin improve in vitro maturation and ultrastructure of oocytes retrieved from estradiol valerate polycystic ovary syndrome-induced rats

et al. 2015

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BackgroundMetformin decreases polycystic ovary syndrome (PCOS) symptoms, induces ovulation, and may improve developmental competence of in vitro oocyte maturation. This study was designed to define the effects of metformin on the characteristics of in vitro oocyte maturation in estradiol valerate (EV) PCOS-induced rats.MethodsForty-five adult female Sprague–Dawley rats were randomly divided into control; sham and PCOS-induced (treated by a single dose of estradiol valerate, 4 mg/rat, IM) groups. The body weight was measured weekly for 12 weeks. At the end of week 12, the serum levels of testosterone, estrogen, progesterone, LH, and FSH and blood glucose of all the rats were measured. About 380 cumulus oocyte complexes (control, 125; sham, 122; PCOS-induced rats, 133) were incubated in Ham’s F10 in the absence and/or presence of metformin (M 5−10) for 12, 24, 36, and 48 h. The cumulus cells expansion and nuclear and cytoplasmic maturation of the oocytes was evaluated using 1 % aceto-orcein staining, and transmission electron microscopy (TEM).ResultsNo significant differences were observed in the body weight of the rats. The serum level of testosterone was reduced, and progesterone and LH were significantly increased in the PCOS-induced rats (p < 0.05). However, no significant differences were observed in the serum levels of estrogen and FSH among the groups. Blood glucose level was higher in the PCOS-induced rats than control, (p < 0.01). The expansion of cumulus cells was observed in the metformin-treated oocytes. The oocytes retrieved from PCOS-induced rats show a stage of meiotic division (GVBD, MI, A-T, and MII) in 57.12 % of metformin-untreated and fairly significantly increased to 64.28 % in metformin-treated oocytes, (p < 0.05), but no differences were observed in the MII stage within groups. The redistribution of some cytoplasmic organelles throughout the ooplasm, particularly the peripheral cortical granules, was defined in the metformin-treated oocytes.ConclusionsSingle dose of EV can creates a reversible PCO adult rat model. Metformin enhances the COCs to initiate meiotic resumption at the first 6 h of IVM. In our study the metformin inability to show all aspects of in vitro oocyte maturation and may be resulted from deficiency of EV to induce PCOS.

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“…Another approach for modifying IVM to improve developmental competence is the use of 2‐step culture where, instead of using pharmacological inhibitors during the initial step, a medium which does not promote nuclear maturation is used (Oliveira e Silva et al. 2011), Development to blastocyst was not evaluated in the latter study; however, Albuz et al.…”

Section: Future Directionsmentioning

confidence: 99%

Bovine Oocyte Meiotic Inhibition Before In Vitro Maturation and Its Value to In Vitro Embryo Production: Does it Improve Developmental Competence?

Bilodeau‐Goeseels

2011

Reprod Domestic Animals

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The efficiency of bovine in vitro embryo production has remained low despite extensive effort to understand the effects of culture conditions, media composition and supplementation. As bovine oocytes resume meiosis spontaneously when cultured, it was hypothesized that preventing meiosis in vitro before in vitro maturation (IVM) and in vitro fertilization (IVF) would allow more oocytes to acquire developmental competence. This article reviews some of the factors involved in meiotic arrest as well as the effects of meiotic inhibition before IVM on bovine oocytes developmental competence following IVF. Follicular components and cAMP-elevating agents can delay or inhibit meiosis in various proportions of oocytes; however, few studies have examined their effects on development following IVM and IVF because they are not practical (follicular components) or have a transient effect on meiosis (cAMP-elevating agents). Protein synthesis or phosphorylation inhibition prevented meiosis in high percentages of oocytes; however, these non-specific inhibitions led to lower developmental competence compared with non-arrested oocytes. Maturation promoting factor (MPF) inhibition with specific inhibitors has been examined in several studies. Despite faster maturation following removal from inhibition and some structural damage to the oocytes, MPF inhibition generally led to blastocyst rates similar to control, non-arrested oocytes. Future work will involve evaluating the effects on arrested oocytes of molecules that can improve developmental competence in non-arrested oocytes. It is also anticipated that new IVM systems that take into consideration new knowledge of the mechanisms involved in the control of meiosis will be developed. Moreover, global gene expression analysis studies will also provide clues to the culture conditions required for optimal expression of developmental competence.

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Induction of reversible meiosis arrest of bovine oocytes using a two-step procedure under defined and nondefined conditions

Cited by 12 publications

References 35 publications

Bovine Oocyte Ability to Embryonic Development When Maturing in Different Two-Phase Culture Systems

Bovine Oocyte Ability to Embryonic Development When Maturing in Different Two-Phase Culture Systems

Does metformin improve in vitro maturation and ultrastructure of oocytes retrieved from estradiol valerate polycystic ovary syndrome-induced rats

Bovine Oocyte Meiotic Inhibition Before In Vitro Maturation and Its Value to In Vitro Embryo Production: Does it Improve Developmental Competence?

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