scholarly journals Effect of aging on follicular function may be relieved by exogenous gonadotropin treatment in a sheep model

Reproduction ◽  
2012 ◽  
Vol 144 (2) ◽  
pp. 245-255 ◽  
Author(s):  
Fiammetta Berlinguer ◽  
Antonio Gonzalez-Bulnes ◽  
Antonio Spezzigu ◽  
Ignacio Contreras-Solis ◽  
Sara Succu ◽  
...  
Keyword(s):  
Young Adult ◽  
Age Groups ◽  
Ovarian Response ◽  
Oocyte Quality ◽  
Developmental Competence ◽  
Reproductive Aging ◽  
Sheep Model ◽  
Mean Values ◽  
Oestrus Cycle

The current study investigated hormonal and ovarian changes during physiological reproductive aging in Sarda ewes. In a first experiment, follicular and corpus luteum dynamics were compared during an induced oestrus cycle in aged (12–14 years) and young adult ewes (4–5 years). Oestrus cycle characteristics did not differ between the two experimental groups. However, follicular function during the follicular phase showed significant alterations in aged ewes, as determined by a lack of dominance effect and by lower mean values of circulating oestradiol (E2) and inhibin levels, compared with young adult ewes. In a second experiment, differences in follicle growth, hormonal milieu and oocyte quality in response to exogenous FSH administration were assessed in aged and adult ewes. No differences were recorded in ovarian response to FSH treatment between young adult and aged ewes, as evaluated by ultrasonographic data and circulating concentrations of LH, E2 and inhibin-A. Although the total number of recovered oocytes was similar in the two age groups, the number of good quality oocytes selected for IVM was significantly lower in aged ewes compared with adult ones. Thereafter, no differences were recorded in cleavage rates, total blastocyst output, embryo developmental kinetic and quality between aged and adult groups. In conclusion, this study demonstrated that reproductive aging in sheep is associated with impaired follicle functionality and an increase in the proportion of oocytes showing morphological abnormalities. However interestingly, oocyte developmental competence in vitro and embryo cryotolerance were not affected by the aging process, when only good quality oocytes were chosen.

268 INFLUENCE OF DONOR AGE ON DEVELOPMENTAL COMPETENCE OF IN VITRO v. IN VIVO MATURED BOVINE OOCYTES OBTAINED BY REPEATED OVUM PICKUP FROM FOLLICLE-STIMULATING-HORMONE-STIMULATED AND NONSTIMULATED ANIMALS

2011 ◽  
Vol 23 (1) ◽  
pp. 232
Author(s):  
M. Matthiesen ◽  
H. D. Reichenbach ◽  
F. A. Habermann ◽  
M. Reichenbach ◽  
G. J. Arnold ◽  
...  
Keyword(s):  
Mixed Model ◽  
Ovarian Function ◽  
Age Groups ◽  
Developmental Competence ◽  
Reproductive Aging ◽  
Donor Age ◽  
Ovarian Aging ◽  
Bovine Oocytes

Recent findings on oogenesis, folliculogenesis, and ovarian aging in cows make the bovine system an attractive model for elucidating ovarian function and dysfunction as well as reproductive aging in women. The aim of the present study was to investigate the influence of donor age on the developmental competence of in vitro v. in vivo matured bovine cumulus–oocyte complexes (COC) obtained by ultrasound-guided repeated ovum pickup (OPU). Two groups (G1 and G2) of German Simmental heifers (14 months old at the beginning of the experiment, n = 5 and n = 7), first-lactation young cows (2–4 y old, n = 5 and n = 3), and old cows (10–15 y old, n = 5 and n = 3) were subjected to twice-weekly OPU without hormonal prestimulation 32 (G1) and 6 times (G2). Afterward, animals in G1 were punctured at 5-week intervals 9 times after FSH superstimulation to obtain in vivo matured COC at the metaphase II stage. Data were analysed using a mixed model (SAS). In the twice-weekly OPU for G1 and G2 combined, significantly (P < 0.05) more COC per animal and OPU session were obtained from the old cows (9.9 ± 1.0) compared with heifers and young cows (6.0 ± 0.8 and 7.0 ± 1.0, respectively). When G1 and G2 were regarded separately, lower numbers of COC (P < 0.01) were obtained in G1 than in G2 (2.7 ± 0.8, 4.4 ± 0.8, 7.0 ± 0.8 and 9.2 ± 1.5, 9.4 ± 2.3, 12.9 ± 2.3 for heifers, young cows, and old cows of G1 and G2, respectively). Cleavage rates (CR) on day 3 after IVF (day 0) were not affected by donor age and were not different between groups. Cultivation of COC from young cows in G1 led to higher blastocyst rates (BR) on day 7 (P < 0.05) compared with old cows and heifers. No differences in BR were observed between animals of G2. Significantly more COC (P < 0.01) were obtained in all age groups from FSH superstimulated donors (10.6 ± 0.8, 9.0 ± 0.9, and 11.7 ± 0.9 for heifers, young cows, and old cows, respectively). Cleavage rates and BR were significantly higher (P < 0.05) in all age groups after FSH superstimulation compared with those of nonstimulated donors. However, there were no differences in CR and BR between age groups (CR: 82.8 ± 7.0, 89.9 ± 7.0, 77.1 ± 6.2%; BR: 34.4 ± 7.2, 44.6 ± 7.2, 36.7 ± 7.2%). We conclude that although the numbers of COC obtained per animal and session were significantly different between G1 and G2, in vitro results were highly repeatable after OPU without hormonal prestimulation. Higher CR and BR were obtained after IVF of in vivo matured COC obtained from FSH superstimulated donors, regardless of animal age. This work was supported by the Deutsche Forschungsgemeinschaft (FOR 1041).

Predictive value of antral follicle count and anti-Müllerian hormone for follicle and oocyte developmental competence during the early prepubertal period in a sheep model

2014 ◽  
Vol 26 (8) ◽  
pp. 1094 ◽  
Author(s):  
Laura Torres-Rovira ◽  
Antonio Gonzalez-Bulnes ◽  
Sara Succu ◽  
Antonio Spezzigu ◽  
Maria E. Manca ◽  
...  
Keyword(s):  
Ovarian Reserve ◽  
Follicular Development ◽  
Primordial Follicle ◽  
Antral Follicle ◽  
Oocyte Quality ◽  
Antral Follicle Count ◽  
Developmental Competence ◽  
Sheep Model ◽  
Ewe Lambs

Circulating anti-Müllerian hormone (AMH) and antral follicle count (AFC) are addressed as suitable markers of oocyte quantity and quality during adulthood. To investigate whether AFC and circulating AMH could predict follicle development and oocyte quality during the prepubertal period we used 40-day-old ewe lambs with high, intermediate and low AFC (≥30, 16–29 and ≤15 follicles respectively). The analysis of the response to the exogenous FSH ovarian reserve test showed a positive correlation between AFC, AMH plasma levels, total follicle number and the number of large follicles (≥3 mm) grown after exogenous FSH administration. The incorporation of abattoir-derived oocytes collected from ovaries with different AFC in an in vitro embryo production system showed that a high AFC can predict oocyte quality in prepubertal ovaries, reflecting an ovarian status suitable for follicular development. The histological quantification of the ovarian reserve evidenced that AFC was not predictive of differences in either the number of healthy follicles or the size of the primordial follicle pool in prepubertal ovaries. Further studies are needed to investigate the implication on the reproductive performance of the significant inter-individual differences found in the present study in AFC and circulating AMH in the early prepubertal period.

P–219 mtDNA content in bovine cumulus cells does not predict oocytés developmental competence

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Á Martíne. Moro ◽  
I Lamas-Toranzo ◽  
L González-Brusi ◽  
A Pérez-Gómez ◽  
P Bermejo-Álvarez
Keyword(s):  
Cumulus Cell ◽  
Cumulus Cells ◽  
Oocyte Quality ◽  
Blastocyst Stage ◽  
Early Embryo ◽  
Developmental Competence ◽  
Success Rates ◽  
Developmental Potential ◽  
Mtdna Sequence

Abstract Study question Does cumulus cell mtDNA content correlate with oocyte developmental potential in the bovine model? Summary answer The relative amount of mtDNA content did not vary significantly in oocytes showing different developmental outcomes following IVF What is known already Cumulus cells are closely connected to the oocyte through transzonal projections, serving essential metabolic functions during folliculogenesis. These oocyte-supporting cells are removed and discarded prior to ICSI, thereby constituting an interesting biological material on which to perform molecular analysis aimed to predict oocyte developmental competence. Previous studies have positively associated oocytés mtDNA content with developmental potential in both animal models and women. However, it remains debatable whether mtDNA content in cumulus cells could be used as a proxy to infer oocyte developmental potential. Study design, size, duration Bovine cumulus cells were allocated into three groups according to the developmental potential of the oocyte: 1) oocytes developing to blastocysts following IVF (Bl+Cl+), 2) oocytes cleaving following IVF but arresting their development prior to the blastocyst stage (Bl-Cl+), and 3) oocytes not cleaving following IVF (Bl-Cl-). Relative mtDNA content was analysed in 40 samples/group, each composed by the cumulus cells from one cumulus-oocyte complex (COC). Participants/materials, setting, methods Bovine cumulus-oocyte complexes were obtained from slaughtered cattle and individually matured in vitro (IVM). Following IVM, cumulus cells were removed by hyaluronidase treatment, pelleted, snap frozen in liquid nitrogen and stored at –80 ºC until analysis. Cumulus-free oocytes were fertilized and cultured in vitro individually and development was recorded for each oocyte. Relative mtDNA abundance was determined by qPCR, amplifying a mtDNA sequence (COX1) and a chromosomal sequence (PPIA). Statistical differences were tested by ANOVA. Main results and the role of chance Relative mtDNA abundance did not differ significantly (ANOVA p &gt; 0.05) between the three groups exhibiting different developmental potential (1±0.06 vs. 1.19±0.05 vs. 1.11±0.05, for Bl+Cl+ vs. Bl-Cl+ vs. Bl-Cl-, mean±s.e.m.). Limitations, reasons for caution Experiments were conducted in the bovine model. Although bovine folliculogenesis, monoovulatory ovulation and early embryo development exhibit considerable similarities with that of humans, caution should be taken when extrapolating these data to humans. Wider implications of the findings: The use of molecular markers for oocyte developmental potential in cumulus cells could be used to enhance success rates following single-embryo transfer. Unfortunately, mtDNA in cumulus cells was not found to be a good proxy for oocyte quality. Trial registration number Not applicable

238 CAFFEINE PREVENTS A LOSS OF CALCIUM OSCILLATORY RESPONSE ASSOCIATED WITH POSTOVULATORY AGING OF MOUSE OOCYTES

2009 ◽  
Vol 21 (1) ◽  
pp. 217
Author(s):  
T. Wakai ◽  
N. Zhang ◽  
R. A. Fissore
Keyword(s):  
Subsequent Development ◽  
Oocyte Quality ◽  
Developmental Competence ◽  
Oscillatory Activity ◽  
Strontium Chloride ◽  
Oocyte Activation ◽  
Mouse Oocytes ◽  
Oocyte Aging ◽  
Postovulatory Aging

Numerous studies have demonstrated that postovulatory aging of oocytes prior to fertilization has detrimental effects on oocyte quality and developmental competence. Oocyte aging is accompanied by abnormal oocyte activation and subsequent development, suggesting a disruption of Ca2+ oscillations after fertilization. The inositol 1,4,5-trisphosphate receptor type 1 (IP3R1) in mammals is responsible for the majority of Ca2+ release during fertilization (Miyazaki S et al. 1993 Dev. Biol.). Previously, we reported that phosphorylation of IP3R1 at an MPM-2 epitope may play an important role in facilitating the induction of Ca2+ oscillations at the MII stage (Lee B et al. 2006 Development), indicating that IP3R1 phosphorylation may be a good indicator of the health of the oocyte. However, few studies have investigated the alteration of the Ca2+ signaling and IP3R1 function associated with oocyte aging. On the other hand, a previous report showed that caffeine increased MPF activity and suppressed fragmentation after parthenogenetic activation of aged oocytes (Kikuchi K et al. 2000 Biol. Reprod.). Therefore, the purpose of the present study was to examine whether and how Ca2+ oscillatory activity changes during oocyte aging and to test if caffeine prevents the negative effects of oocyte aging. MII mouse oocytes were collected 14 h after hCG injection and cultured in vitro for 8, 24 or 48 h with or without caffeine (5 or 10 mm). Oocyte quality was assessed by the occurrence of spontaneous fragmentation, monitoring of Ca2+ oscillations after exposure to 10 mm strontium chloride, Western blot analysis of IP3R1 phosphorylation and immunostaining of IP3R1. In oocytes in vitro aged for 8 h, the duration of the first Ca2+ rise was significantly decreased compared with fresh MII oocytes, although this reduction was not observed in MII oocytes treated with 5 mm caffeine. The phosphorylation of IP3R1 at the MPM-2 epitope was slightly decreased during oocyte aging in both caffeine and noncaffeine treatment. Importantly, whereas IP3R1 in MII oocytes treated for 8 h with 5 mm caffeine displayed the typical cortical cluster organization, IP3R1 in aged oocytes without caffeine became dispersed in the cytoplasm. In addition, caffeine significantly suppressed the spontaneous fragmentation that is normally observed by 48 h of in vitro culture. These results suggest that the Ca2+ oscillatory activity is compromised during oocyte aging and caffeine prevents the loss of integrity of Ca2+ signaling possibly by keeping the cortical distribution of IP3R1.

253 OXIDATIVE STRESS MAY IMPAIR OOCYTE QUALITY IN DAIRY COWS OF REPRODUCTIVE AGE WITH A REDUCED ANTRAL FOLLICLE COUNT

2013 ◽  
Vol 25 (1) ◽  
pp. 274 ◽  
Author(s):  
I. Tessaro ◽  
F. Franciosi ◽  
V. Lodde ◽  
D. Corbani ◽  
A. M. Luciano ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Antral Follicle ◽  
Oocyte Quality ◽  
Antral Follicle Count ◽  
Oxide System ◽  
Reproductive Age ◽  
Developmental Competence ◽  
Mitochondrial Activity

In dairy cattle, oocytes isolated from ovaries with a reduced antral follicle count (AFC) have a low embryonic developmental competence. This may be related to oxidative stress, as indicated by our recent finding that ovaries with reduced AFC show a defective endothelial nitric oxide synthase/nitric oxide system. To further test this hypothesis, we evaluated whether the poor developmental competence of these oocytes was possibly due 1) to an imbalance of the reduced glutathione (GSH) system, because GSH is the major antioxidant compound stored within the oocyte and protects the zygote and early embryos from oxidative damage, and 2) to reduced mitochondrial activity. Ovaries were obtained from the abattoir, and oocytes were collected from ovaries with reduced AFC, with fewer than 10 follicles of 2 to 6 mm in diameter, and aged-matched controls, with more than 10 follicles of 2 to 6 mm in diameter. Oocyte GSH content was evaluated using the 5,5′-dithio-bis(2-nitrobenzoic acid)-GSH reductase recycling micro-GSH assay before and after in vitro maturation (IVM) in the presence or absence of 100 µM cysteamine, a GSH precursor. At the same time the developmental competence after IVF was assessed. Moreover, the mitochondrial activity during IVM was evaluated in additional oocytes from the two ovarian categories by specific MitoTracker dyes (MitoTracker FM Green and MitoTracker Orange CMTMRos, Invitrogen, Carlsbad, CA, USA) and subsequent image analysis (ImageJ software). All data were analysed by ANOVA followed by Fisher’s least significant differences test, and P-values <0.05 were considered significant. Experiments were repeated at least three times. Oocytes isolated from ovaries with a low AFC had a similar GSH content compared with oocytes isolated from control ovaries (n = 65 and 85, respectively; 4.31 ± 0.41 v. 4.51 ± 0.42 pmol oocyte–1). After IVM, oocytes from ovaries with reduced AFC showed a significantly lower GSH content compared with control oocytes (n = 55 and 65, respectively; 4.36 ± 0.31 v. 6.59 ± 0.39 pmol oocyte–1); however, cysteamine supplementation during IVM induced GSH accumulation similar to the control (n = 80 and 85, respectively; 9.88 ± 0.77 v. 10.45 ± 0.88 pmol oocyte–1). It is interesting that the increase in intracellular GSH content significantly improved the developmental competence of oocytes from ovaries with a reduced AFC (n = 196 and 201, respectively; 20.1 ± 2.9% v. 6.2 ± 1.6%), although the blastocyst rate remained lower than the control either with or without cysteamine (n = 218 and 212, respectively; 33.3 ± 3.8% and 34.2 ± 2.4%). Further, immature oocytes from ovaries with a low AFC showed a reduced mitochondrial membrane potential compared with control oocytes (n = 13 and 18, respectively; 1.74 ± 1.19 v. 2.22 ± 1.72, calculated as the ratio between the fluorescence of active and total mitochondria), whereas at the end of IVM, it declined in both categories at a comparable level (n = 17 and 24, respectively; 1.19 ± 0.10 and 1.30 ± 0.06). Our data confirmed the hypothesis that both the GSH imbalance and defective mitochondrial activity contribute to the limited developmental competence of oocytes from ovaries with a reduced AFC. This work was supported by Dote ricerca applicata-FSE, Regione Lombardia, Italy (VL, IT).

205 CUMULUS CELL MORPHOLOGY BEFORE AND AFTER IN VITRO MATURATION AS AN INDICATOR OF PORCINE OOCYTE DEVELOPMENTAL COMPETENCE

2010 ◽  
Vol 22 (1) ◽  
pp. 260
Author(s):  
M. Bertoldo ◽  
P. K. Holyoake ◽  
G. Evans ◽  
C. G. Grupen
Keyword(s):  
Cell Morphology ◽  
In Vitro Maturation ◽  
Cumulus Cell ◽  
Cumulus Cells ◽  
Oocyte Quality ◽  
Developmental Competence ◽  
Oocyte Developmental Competence ◽  
Before And After ◽  
Follicle Size

Effective in vitro maturation (IVM) is essential for successful in vitro embryo production. The morphology of the cumulus investment before and after IVM may be a useful noninvasive indicator of oocyte quality. In pigs, oocyte developmental competence is reduced during the summer months. The aim of this study was to determine whether the morphology of cumulus-oocyte complexes (COC) before and after IVM are associated with oocyte quality, using COC collected from small and large follicles in summer and winter as models of poor and good oocyte quality. Ovaries were collected from sows slaughtered 4 days after weaning. The COC recovered from small (3-4 mm) and large (5-8 mm) antral follicles were morphologically graded and parthenogenetically activated following IVM during winter (n = 1419; 10 replicates) and summer (n = 2803; 10 replicates). Grade 1 and 2 COC had >2 layers of compact cumulus cells and a homogenous cytoplasm. Grade 3 COC were either partially or fully denuded, had a heterogeneous cytoplasm, or were vacuolated or dark in color. Grade 4 COC had expanded cumulus cells. Cumulus expansion was also assessed subsequent to IVM. The COC recorded as having a cumulus expansion index (CEI) of 1 had the poorest expansion with no detectable response to IVM, whereas those with a CEI of 4 had the greatest amount of expansion, including that of the corona radiata. Data were analyzed using a generalized linear mixed model in GenStat® (release 10, VSN International, Hemel Hempstead, UK). There was an effect of follicle size for Grade 1 COC, with COC from large follicles in both seasons yielding better quality COC (P < 0.05). The proportion of COC in Grade 2 was higher in small follicles during winter compared with large follicles, but there were no differences between follicle sizes during summer (P < 0.05). The proportion of COC with CEI 1 was highest in COC from small follicles during summer (P < 0.05). The proportion of COC from large follicles with CEI 2 was higher during summer compared with winter (P < 0.05). There were no seasonal or follicle size effects on COC with CEI 3 or 4 (P > 0.05). The proportion of oocytes that developed to blastocysts was greater in winter than in summer (39.06% ± 5.67 v. 22.27% ± 4.01; P < 0.05). Oocytes derived from large follicles had a greater ability to form blastocysts compared with those from small follicles (37.13% ± 5.65 v. 23.32% ± 4.56; P < 0.06). Morphological assessment of cumulus cells before and after IVM may be a useful tool to evaluate the effects of follicle size on oocyte developmental competence. However, the results of the present study indicate that cumulus cell morphology is not a good indicator of the effect of season on oocyte developmental competence.

Histone deacetylase inhibitor trichostatin A affects porcine oocyte maturation in vitro

2014 ◽  
Vol 26 (6) ◽  
pp. 806 ◽  
Author(s):  
Yong-Xun Jin ◽  
Ming-Hui Zhao ◽  
Zhong Zheng ◽  
Jung-Suk Kwon ◽  
Seul-Ki Lee ◽  
...  
Keyword(s):  
Trichostatin A ◽  
Germinal Vesicle ◽  
Oocyte Quality ◽  
Histone Deacetylation ◽  
Developmental Competence ◽  
Mitogen Activated Protein Kinase ◽  
Control Group ◽  
Germinal Vesicle Breakdown ◽  
Porcine Oocyte

Previous studies show that porcine oocyte aging resulting from asynchronised IVM impairs embryo developmental competence. In the present study we investigated whether trichostatin A (TSA; an inhibitor of histone deacetylation) prolongs the maturation time and prevents the aging of oocytes. Porcine oocytes were cultured in medium containing increasing concentrations of TSA (300 nM) for 24, 44 or 64 h. The percentage of oocytes that underwent germinal vesicle breakdown was significantly lower in the TSA-treated group (300 nM) than in the control group. TSA did not affect oocyte quality at MII based on levels of maturation-promoting factor, the phosphorylation status of mitogen-activated protein kinase or histone H3K9 acetylation analysis. We also compared the preimplantation developmental competence and the viability of pathenogenetic embryos treated with 100 nM TSA for 24 h and then continuously cultured for another 24 h in TSA free condition. No significant differences were observed for either parameter between the TSA-treated and control groups. These results indicate that TSA prolongs the IVM of porcine oocytes but that oocyte quality and aging are not affected. These findings provide a feasible option by which to adjust the initiation time of downstream experiments based on porcine matured oocytes.

scholarly journals DNA damage in cumulus cells generated after the vitrification of in vitro matured porcine oocytes and its impact on fertilization and embryo development

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Alma López ◽  
Miguel Betancourt ◽  
Yvonne Ducolomb ◽  
Juan José Rodríguez ◽  
Eduardo Casas ◽  
...  
Keyword(s):  
Dna Damage ◽  
Embryo Development ◽  
Tail Length ◽  
Cumulus Cells ◽  
Cell Types ◽  
Oocyte Quality ◽  
Blastocyst Stage ◽  
Developmental Competence ◽  
Development Rates

Abstract Background The evaluation of the DNA damage generated in cumulus cells after mature cumulus-oocyte complexes vitrification can be considered as an indicator of oocyte quality since these cells play important roles in oocyte developmental competence. Therefore, the aim of this study was to determine if matured cumulus-oocyte complexes exposure to cryoprotectants (CPAs) or vitrification affects oocytes and cumulus cells viability, but also if DNA damage is generated in cumulus cells, affecting fertilization and embryo development. Results The DNA damage in cumulus cells was measured using the alkaline comet assay and expressed as Comet Tail Length (CTL) and Olive Tail Moment (OTM). Results demonstrate that oocyte exposure to CPAs or vitrification reduced oocyte (75.5 ± 3.69%, Toxicity; 66.7 ± 4.57%, Vitrification) and cumulus cells viability (32.7 ± 5.85%, Toxicity; 7.7 ± 2.21%, Vitrification) compared to control (95.5 ± 4.04%, oocytes; 89 ± 4.24%, cumulus cells). Also, significantly higher DNA damage expressed as OTM was generated in the cumulus cells after exposure to CPAs and vitrification (39 ± 17.41, 33.6 ± 16.69, respectively) compared to control (7.4 ± 4.22). In addition, fertilization and embryo development rates also decreased after exposure to CPAs (35.3 ± 16.65%, 22.6 ± 3.05%, respectively) and vitrification (32.3 ± 9.29%, 20 ± 1%, respectively). It was also found that fertilization and embryo development rates in granulose-intact oocytes were significantly higher compared to denuded oocytes in the control groups. However, a decline in embryo development to the blastocyst stage was observed after CPAs exposure (1.66 ± 0.57%) or vitrification (2 ± 1%) compared to control (22.3 ± 2.51%). This could be attributed to the reduction in both cell types viability, and the generation of DNA damage in the cumulus cells. Conclusion This study demonstrates that oocyte exposure to CPAs or vitrification reduced viability in oocytes and cumulus cells, and generated DNA damage in the cumulus cells, affecting fertilization and embryo development rates. These findings will allow to understand some of the mechanisms of oocyte damage after vitrification that compromise their developmental capacity, as well as the search for new vitrification strategies to increase fertilization and embryo development rates by preserving the integrity of the cumulus cells.

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