Germinal Vesicle Stages in Pig Follicular Oocytes Collected by Different Methods

Nagai, Takashi; Ebihara, Misa; Ōnishi, Akira; Kubo, Michinori

doi:10.1262/jrd.43.339

Cited by 14 publications

(6 citation statements)

References 11 publications

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“…Therefore, GV, GVBD and first polar body (PB1) extrusion observed under stereomicroscope have often been accepted to evaluate the meiotic maturation of mammalian oocytes (Nagai et al 1997;Hunter 2000;Sato et al 2001;Wu et al 2002). In line with previous findings either a-tocopherol or L-ascorbic acid promotes meiotic maturation of DOs, especially from MI to MII.…”

Section: Discussionmentioning

confidence: 91%

“…The ordinary method was used to evaluate the meiotic resumption and maturation according to the morphological characteristics of oocytes. Therefore, GV, GVBD and first polar body (PB1) extrusion observed under stereomicroscope have often been accepted to evaluate the meiotic maturation of mammalian oocytes (Nagai et al. 1997; Hunter 2000; Sato et al.…”

Section: Discussionmentioning

confidence: 99%

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Exposure to L‐Ascorbic Acid or α‐Tocopherol Facilitates the Development of Porcine Denuded Oocytes from Metaphase I to Metaphase II and Prevents Cumulus Cells from Fragmentation

Tao

Zhou

Xia

et al. 2004

Reprod Domestic Animals

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It is known that alpha-tocopherol (vitamin E) and L-ascorbic acid (vitamin C) can modulate many biochemical processes intracellularly or extracellularly as antioxidants. The objective of the present study was to investigate the effects of alpha-tocopherol and L-ascorbic acid on porcine oocyte meiotic maturation, viability and the functions of cumulus cells. In two independent experiments, porcine oocytes with or free from cumulus cells were exposed to different levels of alpha-tocopherol (0, 10, 100 and 200 microM) or L-ascorbic acid (0, 50, 250 and 750 microM). Cumulus expansion, cumulus cell DNA fragmentation, meiotic maturation and degeneration of oocytes were assessed 48 h after in vitro culture. The results showed that: (1) neither alpha-tocopherol nor L-ascorbic acid influenced cumulus expansion but both prevented cumulus cell DNA fragmentation. (2) Alpha-tocopherol lowered the percentage of denuded oocytes (DOs) arrested at germinal vesicle stage (GV). Among the oocytes undergoing germinal vesicle breakdown (GVBD) proportion, fewer DOs treated by alpha-tocopherol were at metaphase I (MI) and more at metaphase II (MII). L-ascorbic acid caused lower percentage of DOs arrested at GV stage and higher percentage of DOs undergoing GVBD, especially at MII. The influences of alpha-tocopherol and L-ascorbic acid were not obvious in cumulus-enclosed oocytes (CEOs). (3) Both vitamins compromised the viability of CEOs and DOs. These results indicate that exposure to alpha-tocopherol or L-ascorbic acid promotes the development of porcine DOs from MI to MII and prevents cumulus cell DNA fragmentation at certain levels, especially 10 microM alpha-tocopherol or 250 microM L-ascorbic acid.

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Exposure to L‐Ascorbic Acid or α‐Tocopherol Facilitates the Development of Porcine Denuded Oocytes from Metaphase I to Metaphase II and Prevents Cumulus Cells from Fragmentation

Tao

Zhou

Xia

et al. 2004

Reprod Domestic Animals

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“…A more reasonable method to assess the quality of oocytes is to ascertain their subsequent developmental ability by fertilization, implantation of embryos and, more desirably, birth of offspring (Kashiwazaki et al, 2001;Kikuchi et al, 2002). However, GV, GVBD (MI) and extrusion of the first polar body (MII) morphologically observed by stereomicroscopy have often been used to evaluate mammalian oocyte meiotic maturation (Nagai et al, 1997;Sato et al, 2001;Hunter, 2000). It was reported that the majority of porcine oocytes cultured for 48 h without a polar body were at MI (73%) and those with a first polar body at MII (94%) (Kikuchi et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

Effects of nitric oxide synthase inhibitors on porcine oocyte meiotic maturation

Tao

Xie

Hong

et al. 2005

Zygote

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As an important biological messenger, nitric oxide (NO) exhibits a wide range of effects during physiological and pathophysiological processes, including mammalian oocyte meiotic maturation. The present study investigated whether NO derived from two nitric oxide synthase (NOS) isoforms, inducible NOS (iNOS) or endothelial NOS (eNOS), is involved in the meiotic maturation of porcine oocytes. Meanwhile, the cumulus cells' function in meiotic maturation and their interaction with oocyte development and degeneration were also investigated using cumulus-enclosed oocytes (CEOs) and denuded oocytes (DOs). Different inhibitors for NOS were supplemented to the medium. Cumulus expansion, cumulus cell DNA fragmentation and oocyte meiotic resumption were evaluated 48 h after incubation. Aminoguanidine (AG), a selective inhibitor for iNOS, suppressed cumulus expansion and inhibited CEOs to resume meiosis (p < 0.05), but did not inhibit cumulus cell DNA fragmentation. Both Nω-nitro-L-arginine (L-NNA) and Nω-nitro-L-arginine methyl ester (L-NAME), inhibitors for both iNOS and eNOS, delayed cumulus expansion, inhibited cumulus cell DNA fragmentation and inhibited CEOs to resume meiosis. Such effects were not seen in DOs. These results indicate that iNOS-derived NO is necessary for cumulus expansion and meiotic maturation by mediating the function of the surrounding cumulus cells, and eNOS-derived NO is also involved in porcine meiotic maturation.

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“…Most of these oocytes are in the GV I stage of nuclear phase [28,29]. GV I stage is the nuclear phase in which fully grown dictyate arrest oocytes prior to restarting meiotic division [27], and the TCM199-based IVM system provide a uniform group of fully grown oocytes at the GV I stage for IVM.…”

Section: Discussionmentioning

confidence: 99%

Developmental Competence of In Vitro Matured Porcine Oocytes after Electrical Activation.

Kurihara

Kurome

Wako

et al. 2002

Journal of Reproduction and Development

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Abstract. Developmental competence of in vitro matured porcine oocytes obtained by TCM199-and NCSU 23-based IVM systems after electrical activation were compared. When the nuclear phase of granulosa-cumulus-oocyte complexes (GCOCs) used in the TCM199-based IVM system and cumulusoocyte complexes (COCs)used in the NCSU 23-based IVM system were observed, most of GCOCs were fully grown dictyate arrest oocytes (GV I, 68.6%), on the other hand, only 33.8% of COCs were at GV I stage. There were no differences in the rates of maturation (93.2%, 82/88 vs 91.3%, 63/69), normal cleavage (70.7%, 58/82 vs 65.1%, 41/63) and development to blastocysts (37.8%, 31/82 vs 34.9%, 22/63) between the in vitro matured oocytes obtained by the two IVM systems. However, the parthenogenetic blastocysts derived from the NCSU23-based IVM system had higher cell numbers than the blastocysts derived from the TCM199-based IVM system (35.6 ± 4.5 vs 22.6 ± 2.0; P<0.01). Transfer of parthenogenetic oocytes derived from the NCSU23-based IVM system resulted in a high developmental rate to somite stage fetuses (26.9%, 45/167). These data demonstrate that the activated porcine oocytes derived from the two IVM systems had equal ability of in vitro development, though there was a difference in the cell number of the parthenogenetic blastocysts. It was also shown that in vitro matured oocytes obtained by the NCSU23-based IVM system had excellent ability of parthenogenetic development to fetuses, indicating that they are usable in porcine developmental engineering.

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Germinal Vesicle Stages in Pig Follicular Oocytes Collected by Different Methods

Cited by 14 publications

References 11 publications

Exposure to L‐Ascorbic Acid or α‐Tocopherol Facilitates the Development of Porcine Denuded Oocytes from Metaphase I to Metaphase II and Prevents Cumulus Cells from Fragmentation

Exposure to L‐Ascorbic Acid or α‐Tocopherol Facilitates the Development of Porcine Denuded Oocytes from Metaphase I to Metaphase II and Prevents Cumulus Cells from Fragmentation

Effects of nitric oxide synthase inhibitors on porcine oocyte meiotic maturation

Developmental Competence of In Vitro Matured Porcine Oocytes after Electrical Activation.

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