Bovine oocyte diameter in relation to developmental competence

Otoi, Takeshige; Yamamoto, Ken; Koyama, Nobuyuki; Tachikawa, S.; Suzuki, Takahiro

doi:10.1016/s0093-691x(97)00300-2

Cited by 120 publications

(102 citation statements)

References 20 publications

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“…This could easily be explained by the fact that an embryo fully depends on maternal cytoplasm until the maternal embryonic genome transition takes place from the 8-to 16-cell stage, since no (or very few) mRNAs are formed until then (Rodriguez & Farin 2004). Fully mature cytoplasm of the oocyte provides the embryo with a battery of maternal mRNAs, proteins, and mitochondria, which are related to oocyte development competence and which may contribute to apoptotic pathways but also to defense mechanisms against apoptosis (Fair et al 1995, Otoi et al 1997, Stojkovic et al 2001. Microinjection of healthy cytoplasm protected oxidative-stressed zygotes from apoptotic death in mice (Liu & Keefe 2000) and improved fertility in older patients with compromised embryos in humans (Cohen et al 1998, Barritt et al 2001.…”

Section: Discussionmentioning

confidence: 99%

“…Although previous studies in bovine have linked oocyte diameter and early developmental kinetics with blastocyst formation and viability (Van Soom et al 1992, Grisart et al 1994, Fair et al 1995, Otoi et al 1997, their relation with the incidence of apoptosis during embryo development remains unexplored. Suboptimal culture conditions undoubtedly contribute to embryonic apoptosis, but the intrinsic quality of the oocyte and the embryo may also be a causative factor.…”

Section: Introductionmentioning

confidence: 99%

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Temporal detection of caspase-3 and -7 in bovine in vitro produced embryos of different developmental capacity

Vandaele

Mateusen²,

Maes³

et al. 2007

Reproduction

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Embryo quality is most frequently evaluated at the blastocyst stage, although quality parameters further back along the developmental axis, such as early developmental kinetics or oocyte quality, can be equally valuable. Despite the fact that previous studies in bovine have linked oocyte diameter and early developmental kinetics with blastocyst formation and viability, their relation with the incidence of apoptosis during embryo development remains relatively unexplored. Therefore, we related noninvasive parameters of oocyte and embryo quality, such as embryo kinetics, embryo morphology, and oocyte diameter, to the incidence of apoptosis throughout embryo development using fluorescent detection of active caspase-3 and -7. First, bovine in vitro embryos were selected according to developmental kinetics and morphology at four set times during culture and subjected to fluorescent detection of active caspase-3 and -7. Caspase activity was significantly higher in slow developing embryos in comparison with fast cleavers (P!0.05), but was not related to embryo morphology. Second, bovine oocytes were divided into three groups on the basis of oocyte diameter and the resulting embryos were used for staining at the same four set times. Caspase activity was significantly higher in embryos derived from growing oocytes compared with those of fully grown oocytes at 45, 80, and 117 hours post-insemination (hpi; P!0.05), but not at 168 hpi. Reproduction (2007) 133 709-718

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Temporal detection of caspase-3 and -7 in bovine in vitro produced embryos of different developmental capacity

Vandaele

Mateusen²,

Maes³

et al. 2007

Reproduction

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“…During the period of oocyte growth, the bovine oocyte increases in size from an intra-zonal diameter of less than 30 µm in primordial follicles to greater than 120 µm in tertiary follicles . Bovine oocyte competence has been examined by evaluating fertilization rate, cleavage rate, proportion of embryos that reach the blastocyst stage, as well as embryo quality (Otoi et al, 1997;Hendricksen et al, 2000; with increased oocyte competence observed in oocytes of larger size (Otoi et al, 1997) and originating from larger follicles (Arlotto et al, 1996;Hendricksen et al, 2000;.…”

Section: Oocyte Determinants Of Fertilitymentioning

confidence: 99%

Effect of preovulatory follicle maturity on pregnancy establishment in cattle: the role ofoocyte competence and the maternal environment

Dickinson¹,

Geary²,

Monnig³

et al. 2016

Anim Reprod

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Reproductive technologies to synchronize estrus and ovulation in cattle have enhanced the ability to practically utilize artificial insemination to increase both genetic merit and reproductive management of beef and dairy herds. The ability to successfully synchronize a follicular wave and ovulation, in heifers and cows, has improved substantially in recent years. Consequently, pregnancy rates to a single fixed-time artificial insemination (FTAI) can approximate that of insemination following spontaneous estrus. Despite these advances, a subset of heifers and cows often has a physiologically immature dominant follicle at the time of GnRH-induced ovulation. These animals will exhibit reduced pregnancy rates and decreased embryonic survival if a pregnancy happens to become established. The physiological mechanisms underlying the preceding decreased fertility have been a focus of our laboratories and may include an effect of the follicular microenvironment on both oocyte competence and the maternal environment. Oocytes must have adequate opportunity to complete cytoplasmic and molecular maturation during the final stages of oocyte maturation that occur within the preovulatory follicle. Follicular status, during the proestrus period, must be such that adequate circulating concentrations of estradiol are present before FTAI to increase oviductal transport of gametes and enhance both the luteinizing capacity of granulosa cells and progesterone receptor population in the post-ovulatory uterus. Following ovulation, the follicle's transformation to a functional corpus luteum to secrete adequate amounts of progesterone is essential for the establishment of pregnancy. The physiological status of the preovulatory follicle, prior to FTAI, greatly affects the concepts discussed above and has an important impact on pregnancy establishment and maintenance in cattle.

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“…It has been suggested that the dog oocyte must be at least 110 |iM in diameter to be able to resume meiosis (Otoi et al, 1997(Otoi et al, , 2001). However, oocyte size does not appear to be the sole limiting factor influencing in vitro maturation success, largely because only a small proportion of oocytes of this size (~ 14%) actually develop to Mil stage in culture (Nickson et al, 1993;Otoi et al, 1997;Hewitt and England, 1998).…”

Section: Introductionmentioning

confidence: 99%

“…However, oocyte size does not appear to be the sole limiting factor influencing in vitro maturation success, largely because only a small proportion of oocytes of this size (~ 14%) actually develop to Mil stage in culture (Nickson et al, 1993;Otoi et al, 1997;Hewitt and England, 1998). Perhaps more significant is follicular size.…”

Section: Introductionmentioning

confidence: 99%

Size of the donor follicle, but not stage of reproductive cycle or seasonality, influences meiotic competency of selected domestic dog oocytes

Songsasen

Wildt

2005

Mol. Reprod. Dev.

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Ability of ovarian oocytes from tine domestic dog to complete nuclear maturation in vitro (IVM) varies markedly among donors and generally is 20% or less of all oocytes cultured. To identify the cause(s) underlying these significant variations in meiotic maturation (to metaphase II; Mil), we retrospectively analyzed data from 1,643 oocytes recovered from 90 bitches for which stage of reproduction and season of year were known. Neither stage of reproduction (proestrus/estrus, diestrus, anestrus, or prepuberty) nor season (P>0.05) influenced the ability of oocytes to achieve nuclear maturation in vitro. A second study was conducted to examine the impact of follicular size on meiotic maturation. Populations of large oocytes were recovered from four categories of follicles (ranging from <0.5 to >2 mm in diameter) and cultured in TCM 199 for 48 hr. Follicular size influenced (P<0.05) meiotic competence. Mean percentages of Mil oocytes were 16.9 ±9.2, 26.1 ±7.6, 38.4±9.2, and 79.5± 10.9 for oocytes recovered from <0.5 mm, >0.5-2 mm diameter follicles, respectively. In summary, stage of reproduction and season have no impact on the ability of dog oocytes to achieve nuclear maturation in vitro. However, we demonstrated for the first time that dog oocytes acquire meiotic competency during follicular development. IVM success of selected oocytes from large size follicles (almost 80%) is about 60% higher than measured in most previous studies involving randomly collected oocytes.Mol. Reprod. Dev.

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Bovine oocyte diameter in relation to developmental competence

Cited by 120 publications

References 20 publications

Temporal detection of caspase-3 and -7 in bovine in vitro produced embryos of different developmental capacity

Temporal detection of caspase-3 and -7 in bovine in vitro produced embryos of different developmental capacity

Effect of preovulatory follicle maturity on pregnancy establishment in cattle: the role ofoocyte competence and the maternal environment

Size of the donor follicle, but not stage of reproductive cycle or seasonality, influences meiotic competency of selected domestic dog oocytes

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