Nuclear Configuration, Spindle Morphology and Cytoskeletal Organization of <i>In Vivo</i> Maturing Horse Oocytes

Siddiqui, M.A.R.; Gastal, E.L.; Ju, Jyh-Cherng; Gastal, M.O.; Beg, M.A.; Ginther, O.J.

doi:10.1111/j.1439-0531.2008.01105.x

Cited by 10 publications

(14 citation statements)

References 32 publications

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“…In the present study, we did not evaluate oocyte maturation stage; however, all oocytes had compact cumulus cells upon microscopic evaluation, which is consistent with immature oocytes (germinal vesicle stage) in our laboratory. Staining of oocytes 30 h after human chorionic gonadotrophin (hCG) revealed that 76% and 11% were at the MII and MI stages, respectively (Siddiqui et al 2009). In addition, in vitro-matured equine oocytes reached the MII stage at a rate of 0%, 0%, 11% and 69% after 4, 12, 20 and 30 h of culture, respectively (Li et al 2006).…”

Section: Discussionmentioning

confidence: 99%

Effects of aging on gene expression and mitochondrial DNA in the equine oocyte and follicle cells

Campos‐Chillon

Farmerie

Bouma

et al. 2015

Reprod. Fertil. Dev.

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We hypothesised that advanced mare age is associated with follicle and oocyte gene alterations. The aims of the study were to examine quantitative and temporal differences in mRNA for LH receptor (LHR), amphiregulin (AREG) and epiregulin (EREG) in granulosa cells, phosphodiesterase (PDE) 4D in cumulus cells and PDE3A, G-protein-coupled receptor 3 (GPR3), growth differentiation factor 9 (GDF9), bone morphogenetic protein 15 (BMP15) and mitochondrial (mt) DNA in oocytes. Samples were collected from dominant follicles of Young (3-12 years) and Old (≥20 years) mares at 0, 6, 9 and 12h after administration of equine recombinant LH. LHR mRNA declined after 0h in Young mares, with no time effect in Old mares. For both ages, gene expression of AREG was elevated at 6 and 9h and EREG was expression was elevated at 9h, with higher expression in Old than Young mares. Cumulus cell PDE4D expression increased by 6h (Old) and 12h (Young). Oocyte GPR3 expression peaked at 9 and 12h in Young and Old mares, respectively. Expression of PDE3A increased at 6h, with the increase greater in oocytes from Old than Young mares at 6 and 9h. Mean GDF9 and BMP15 transcripts were higher in Young than Old, with a peak at 6h. Copy numbers of mtDNA did not vary over time in oocytes from Young mares, but a temporal decrease was observed in oocytes from Old mares. The results support an age-associated asynchrony in the expression of genes that are essential for follicular and oocyte maturation before ovulation.

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Section: Discussionmentioning

confidence: 99%

Effects of aging on gene expression and mitochondrial DNA in the equine oocyte and follicle cells

Campos‐Chillon

Farmerie

Bouma

et al. 2015

Reprod. Fertil. Dev.

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“…Mammalian oocytes that are atypical in the progression of meiotic maturation displayed aberrant configurations of microtubules and abnormal chromosome Effect of eGH on IVM of equine oocytes morphology (De La Fuente, 2006). Recently, Siddiqui et al (2009) reported a rate of 11% of atypical equine oocytes recovered in vivo showing apparent abnormalities of the microtubules organization. In agreement with reports on mouse oocytes, we also observed that a few oocytes (around 10%) had a scattered and disorganized aggregation of chromatin and microtubules.…”

Section: Discussionmentioning

confidence: 99%

“…We observed that cytoskeleton changes were more evident in the majority of oocytes matured in the presence of eGH, E 2 , gonadotropins and FCS group. Siddiqui et al (2009) reported rates of 89% of oocytes reaching M-I and M-II stages of development on the basis of nuclear configuration, spindle morphology and cytoskeleton organization using fluorescent probes to evaluate horse oocytes collected in vivo from human chorionic gonadotropinstimulated mares. The results from the present study are in agreement with a report (Tremoleda et al, 2003) that described cytoskeletal changes of equine oocytes before fertilization by intracytoplasmic sperm injection and also in equine embryos.…”

Section: Discussionmentioning

confidence: 99%

“…Reports of horse oocyte development have focused on evaluating changes in chromatin configuration (Hinrichs et al, 1993;Siddiqui et al, 2009), mitochondrial organization (Torner et al, 2007), as well as nuclear and cytoplasmic changes during oocyte maturation (Carneiro et al, 2002). However, there is limited evidence on whether cytoskeleton distribution remains intact after IVM of equine oocytes cultured with additional growth factors.…”

Section: Introductionmentioning

confidence: 99%

“…Assessments of the migration of cortical granules, formation of meiotic spindle and integrity of the cytoplasmic membrane have been used as indicators of oocyte maturity and integrity (Tremoleda et al, 2001;Carneiro et al, 2002;Siddiqui et al, 2009). However, for an oocyte to achieve maturity, none of these parameters alone is a true indicator of oocyte competence for fertilization.…”

Section: Introductionmentioning

confidence: 99%

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Influence of equine growth hormone, insulin-like growth factor-I and its interaction with gonadotropins on in vitro maturation and cytoskeleton morphology in equine oocytes

Pereira

Lorenzo

Carneiro

et al. 2013

Animal

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In horses, successful in vitro fertilization procedures are limited by our inability to consistently mature equine oocytes by in vitro methods. Growth hormone (GH) is an important regulator of female reproduction in mammals, playing an important role in ovarian function, follicular growth and steroidogenesis. The objectives of this research were to investigate: the effects of equine growth hormone (eGH) and insulin-like growth factor-I (IGF-I) on the in vitro maturation (IVM) of equine oocytes, and the effects of eGH in addition to estradiol (E 2 ), gonadotropins (FSH and LH) and fetal calf serum (FCS) on IVM. We also evaluated the cytoskeleton organization of equine oocytes after IVM with eGH. Equine oocytes were aspirated from follicles ,30 mm in diameter and matured for 30 h at 38.58C in air with 5% CO 2 . In experiment 1, selected cumulus-oocyte complexes (COCs) were randomly allocated as follows: (a) control (no additives); (b) 400 ng/ml eGH; (c) 200 ng/ml IGF-I; (d) eGH 1 IGF-I; and (e) eGH 1 IGF-I 1 200 ng/ml anti-IGF-I. In addition to these treatment groups, we also added 1 mg/ml E 2 , 5 IU/ml FSH, 10 IU/ml LH and 10% FCS in vitro (experiment 2). Oocytes were stained with markers for microtubules (anti-a-tubulin antibody), microfilaments (AlexaFluor 488 Phalloidin) and chromatin (TO-PRO 3 -iodide) and assessed via confocal microscopy. No difference was observed when eGH and IGF-I was added into our IVM system. However, following incubation with eGH alone (40%) and eGH, E 2 , gonadotropins and FCS (36.6%) oocytes were classified as mature v. 17.6% of oocytes in the control group (P , 0.05). Matured equine oocytes showed that a thin network of filaments concentrated within the oocyte cortex and microtubules at the metaphase spindle showed a symmetrical barrel-shaped structure, with chromosomes aligned along its midline. We conclude that the use of E 2 , gonadotropins and FCS in the presence of eGH increases the number of oocytes reaching oocyte competence.

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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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Nuclear Configuration, Spindle Morphology and Cytoskeletal Organization of In Vivo Maturing Horse Oocytes

Cited by 10 publications

References 32 publications

Effects of aging on gene expression and mitochondrial DNA in the equine oocyte and follicle cells

Effects of aging on gene expression and mitochondrial DNA in the equine oocyte and follicle cells

Influence of equine growth hormone, insulin-like growth factor-I and its interaction with gonadotropins on in vitro maturation and cytoskeleton morphology in equine oocytes

The equine oocyte: Factors affecting meiotic and developmental competence

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