Oocyte Maturation

... Molly AH Webb, Joel P. Van Eenennaam, Serge I. Doroshov * and Gary P. Moberg. ... (1996b). The antibody was a gift from Dr. Y. Nagahama (Institute of Basic Biology, Tokyo). ... Pankhurst et al. (1996) found that rainbow trout, Oncorhynchus mykiss, exposed to elevated water ...

Background: In-vitro fertilization is a known risk factor for ectopic pregnancies. We sought to establish the risk factors for ectopic pregnancy in GnRH antagonist cycles examining patient and stimulation parameters with an emphasis on ovulation trigger. Methods: We conducted a retrospective, cohort study of 343 patients undergoing 380 assisted reproductive technology (ART) cycles with the GnRH antagonist protocol and achieving a clinical pregnancy from November 2010 through December 2015.

The present manuscript summarizes the research, which is currently going on in our department regarding the interaction between negative energy balance (NEB) and fertility in modern high yielding dairy cows. In this work, it has been clearly demonstrated that nearly 50% of the recently calved dairy cows suffer from one or another ovarian dysfunc- tion during the preservice postpartum period. Both clinical signs of a significant negative energy balance as well as the occurrence of puerperal disorders were main risk factors to suffer from these ovarian problems. In the following research using repeated ovum pick sessions it was demonstrated that homeorhetic changes of metabo- lites known as typical indicators of the negative energy balance, were reflected in the follicular fluid of the dominant folli- cle during the immediate postpartum period. Based on in vitro experiments it was furthermore shown that these metabo- lites were able to affect bovine granulosa cells at concentrations, ...

In current in vitro production (IVP) systems, oocytes lack in vivo dominant and preovulatory follicular development, which may compromise pregnancy and viability of calves born. When an oocyte sets off in vivo on the road toward fertilization, it contains numerous transcripts and proteins necessary to survive the first few cell cycles of embryonic development. It is not yet known during which period of development the oocyte builds up the store, possibly primarily during the major growth phase of the oocyte, which is completed at the time a follicle reaches the size of 3 mm. Here, we investigated to what extent the later phases of follicular development, such as prematuration in the dominant follicle before the LH surge and ensuing final maturation in the preovulatory follicle, contribute to oocyte competence and development into viable blastocysts. Recent studies on in vivo vs in vitro oocyte maturation employed oocytes from an identical preovulatory development by applying ovum pick-up (OPU) twice (before and 24 h after the LH surge) in each cow treated for superovulation with a controlled LH surge. The embryo recovery rates at Day 7 of IVC after IVF were similar: 44% () for in vivo- vs 41% () for in vitro-matured oocytes, which shows that the natural environment during final maturation is not essential for the mere in vitro development of the prematured oocyte beyond the 8- to 16-cell stage. However, in vivo maturation appeared to contribute to the oocyte's quality in a more subtle way, as indicated by a significant increase in the proportion of expanded blastocysts and a more physiological degree of chromosome aberrations of the embryos. In blastocysts derived from in vivo-matured oocytes, 21% of the embryos were mixoploid vs 50% from in vitro-matured oocytes, concomitant with a higher number of cells (96 vs 54 per normal blastocyst). The expression pattern of a set of six developmentally important genes was, however, not significantly altered in blastocysts derived from in vivo-matured oocytes. Certain deviations were observed compared with the levels of entirely in vivo-developed control blastocysts, which suggests that the beneficial effects of in vivo maturation are possibly exerted at initial stages of embryonic development. Prematuration in vivo, occurring in a dominant follicle developing from about 8 mm into the preovulatory follicle, is accompanied by changes in protein synthesis of the cumulus oocyte complex (COC). Presumably, the differentially expressed proteins are involved in equipping the oocyte with further developmental competence. Although we have unraveled some important biochemical and cellular biological features of the oocyte, further research on in vivo processes is essential to improve in vitro embryo production in practice.

Aging-related intervention by anti-mullerian hormone (AMH) on ART profile were retrospectively examined, and ART outcome of different AMH categories (<1.0, 1.0-3.5, >3.5) was compared. Overall, increased AMH accompanying with endogenous FSH decrement improved oocyte retrieval and maturation. Of those 112 cycles recruited, 77% had ≥1 ng/ml AMH, which accompanied with a significant (p<0.05) reduction in endogenous FSH and age. Improved oocyte retrieval and maturation resulted in better pregnancies than did cycles with <1 ng/ml AMH. A significant decrease in AMH was detected in patients ≥35 years old and great increase in the number of ET embryos in patients maintaining high AMH levels resulted marked increase of the pregnancy rate (11% vs. 69%). However, most AMH effects were disappeared in the 30-34 years group. These results demonstrated that endogenous AMH influenced ART outcomes, and the effect was prominent in patients aged beyond 35 years old, which can predict ART outcomes in middle-aged, infertile patients.

The advent of recombinant gonadotrophins brought significant changes in fertility therapy. Treatment options with recombinant gonadotrophins add more to knowledge on folliculogenesis and ovarian steroidogenesis. Over a decade, recombinant LH (rLH) has been used for clinical trials, and the amount of peripheral LH that is necessary for optimal follicular growth, oocyte maturation, subsequent embryo development and assisted reproduction outcome during ovulation induction can now be better evaluated. This review evaluates the effect of rLH supplementation on ovarian stimulation and assisted reproduction outcome. The studies conducted with rLH supplementation in ovarian stimulation in different groups of patients and in cases of controlled ovarian stimulation are clearly discussed in this review.

The present study was conducted to elucidate the applicability of body condition score (BCS) and locomotion score (LMS) to predict the reproductive and health performance of cows in intensive manage dairy herd in upcountry dairy farm in Sri Lanka. BCS and LMS were scored using 1 to 5 point score system. Forty three (n=43) pregnant cows and forty six (n=46) early lactating cows were selected for the study. Fertility was measured from farm records based on conception rate and length of postpartum anestrus of the selected herds. BCS level 2 to 4 has shown the lowest postpartum length. Under the given conditions, BCS<2 level has shown 70.75±4.09 days of post-partum length, where BCS 2-4 level has shown 34.4±2.15 days of post-partum anestrus length. This was the lowest recoded postpartum anestrus length during the study period. Low LMS was also associated with the lowest post-partum length compared to other groups (56.29±5.29 in LMS<2, 47.16±5 in LMS >2, 36±1.15 in control). There was significant (P<0.0075) effect of BCS on retained placenta condition. LMS has significant (P<0.0098) impact on retained placenta condition. There was no significant effect (P>0.2547) of body condition score on dystocia. A significant effect (P<0.0163) of lameness condition was observed on dystocia. Higher lameness condition score has shown significant effect (P<0.0098) on increasing incidents of endometritis. Poor body condition score has recorded significant effect to the lowering conception rate (P<0.0026). In conclusion, BCS and LMS have direct relationship with the reproductive performance and herd health parameters of dairy cattle, therefore the BCS and LMS can be effectively used to predict the reproductive performance in dairy cattle in the herds under intensive management system.
Keywords: Body condition score, locomotion score, postpartum anestrus length, reproductive performance

Background: Ovarian oogenesis is under the control of gonadotropins. In the human ovary, each fully grown oocyte resumes maturation in response to gonadotrophins. This process is completed after oocytes reach metaphase stage of second meiotic division (MII) stage. The aim of this prospective, clinical trial was to perceive the age and BMI effect on oocytes maturation and embryos development in women undergoing control ovarian hyperstimulation. Method: A total of 40 infertile women undergoing ovarian hyperstimulation their age range between 18-40 y old were included in this study using two type of protocol: long agonist and antagonist. Result: Significant negative correlation was observed between the age and the number of retrieved MII oocytes. Significant negatively effects of the BMI on the number of MII oocytes while significant positive correlation between the BMI and the fertilization rate was noticed. Conclusion: There are negative effects of age and BMI on the oocytes number and quality.

Background: Effect of different doses of cysteamine on rate of in vitro maturation (IVM), in vitro fertilization (IVF) and glutathione (GSH) level was studied. Metaphase II (MII) spindle area was analyzed for quantification of shape and size of oocytes. Methods: Female mice were primed with 5 IU of pregnant mare&#39;s stimulating gonadotrophin. Germinal vesicle (GV) oocytes were retrieved 48 hrs

Our purpose was to determine whether there is a correlation between human chorionic gonadotropin (hCG) blood levels and oocyte maturation. Three samples of blood were obtained at different times from hCG administration as follows: 12 hr, 36 hr, during oocyte recovery, and at 84 hr, when the patient comes for embryo transfer. A total of 5036 oocytes was retrieved from 404 patients prospectively recruited between April 1996 and March 1997. The percentage of metaphase-II oocytes at different blood levels ranged from 84 to 88%. The general trend does not show any significant increase in percentage of metaphase-II oocytes in association with an increasing serum hCG concentration. The results of this study suggest that at 12, 36, and 84 hr after hCG administration, levels as low as 50, 45, and 9 IU/L of hCG, respectively, are equally potent as higher levels at initiating maximal oocyte maturity.

A change in the elasticity of mouse zona pellucida was quantitatively evaluated during oocyte maturation, fertilization and early embryo development. Young&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s modulus of zona pellucida of germinal vesicle (GV), metaphase-II (MII), pronuclear (PN), 2cell, 4cell, 8cell, morulae (M) and early blastocyst (EB) stages was measured using a micro tactile sensor (MTS) and a chamber exclusively designed for the measurement. The MTS has very high sensitivity and a deformation of only 5 microm was sufficient to calculate the Young&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s modulus and the oocyte/embryo maintained its original spherical shape during the measurement. The Young&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s modulus of GV, MII, PN, 2cell, 4cell, 8cell, M and EB was 22.8+/-10.4 kPa (n=30), 8.26+/-5.22 kPa (n=74), 22.3+/-10.5 kPa (n=66), 13.8+/-3.54 kPa (n=41), 12.6+/-3.34 kPa (n=19), 5.97+/-4.97 kPa (n=6), 1.88+/-1.34 kPa (n=8) and 3.39+/-1.86 kPa (n=4), respectively. Experimental results clearly demonstrated that the mouse zona pellucida hardened following fertilization. Interestingly, once the zona pellucida hardened at the PN stage, it gradually softened as the embryo developed (i.e. it was found that the zona hardening is a transient phenomenon). Furthermore, the zona pellucida of the GV oocyte was as hard as that of the PN embryo and became soft as it matured to the MII stage. In addition, the safety of the MTS measurement for oocytes and embryos was discussed both theoretically and experimentally.

Oxidative stress is involved in the aetiology of defective embryo development. Reactive oxygen species (ROS) may originate from embryo metabolism and/or embryo surroundings. Embryo metabolism generates ROS via several enzymatic mechanisms. The relative contribution of each source seems different depending on the species, the stage of development, and the culture conditions. Several exogenous factors and culture conditions can enhance the production of ROS by embryos. ROS can alter most types of cellular molecules, and also induce development block and retardation. Multiple mechanisms of embryo protection against ROS exist, and these have complementary actions. External protection, present in follicular and tubal fluids, mainly comprises non-enzymatic antioxidants such as hypotaurine, taurine and ascorbic acid. Internal protection mainly comprises antioxidant enzymes: superoxide dismutase, glutathione peroxidase and gamma-glutamylcysteine synthetase. Transcripts encoding for these enzymes are present in the oocyte, embryo and oviduct. It may be important that these transcripts are stored during oocyte maturation in order to allow the embryo to acquire the aptitude to develop. It is now common to add antioxidant compounds to culture media. Nevertheless, maintaining the pro-oxidant-antioxidant equilibrium in embryos through such supplementation is a complex problem. Further studies are necessary to limit oxidative stress during embryo culture.

The aim of this study was to evaluate the influence of different bi-phasic systems with gonadotrophins and steroids on in vitro maturation rates of oocytes obtained from bitches at different reproductive stages (follicular, luteal, anoestrous). In System A (control) oocytes were matured for 72 h in base medium (BM) with 10 IU mL
1 human chorionic gonadotrophin (hCG), 1 mg mL
1 progesterone (P4) and 1 mg mL
1 oestradiol (E2); in bi-phasic System B oocytes were matured for 48 h in BM with hCG and for 24 h in BM with P4; in bi-phasic System C oocytes were matured for 48 h in BM with hCG, P4 and E2, and for 24 h in BM with P4; in System D, oocytes were cultured in BM without hormonal supplementation. Data were analysed by ANOVA. There was a positive effect of the bi-phasic systems on germinal vesicle breakdown, metaphase I and metaphase II rates, irrespective of reproductive status (P , 0.05). Bi-phasic systems were also beneficial for cortical granule distribution (an indication of cytoplasmic maturation) and its relationship to nuclear status: 74.5% of the oocytes cultured in System B and 85.4% of those cultured in System C presented both nuclear and cytoplasmic maturation (P , 0.001). The stage of the oestrous cycle did not influence maturation rates.