Oocyte cytoplasmic evaluation is based on homogeneity and granular appearance. Our study investigated if a granular cytoplasm, highly heterogeneous, would affect oocyte competence in bovine. In two experiments, bovine cumulus–oocyte complexes (COCs) with homogeneous cytoplasm (control, CC) and granulated cytoplasm (granular, GC) were selected from a regular pool of COCs. Experiment 1 was performed with slaughterhouse ovaries, and Experiment 2 was carried out in Girolando COCs obtained from ovum pick-up. Granular oocytes had higher caspase 3 levels (66.17 ± 11.61 vs 172.08 ± 16.95, P < 0.01) and similar GAP junction activity (5.64 ± 0.45 vs 6.29 ± 0.29). ZAR1 relative mRNA amount was lower in granular oocytes (178.27 ± 151.63 vs 0.89 ± 0.89, P = 0.01) and no effect was detected for MATER, PPP2R1A, ENY2, IGF2R, and BMP15 genes. Despite molecular differences, no detrimental effect was detected on oocyte competence in GC oocytes. Cleavage (Experiment 1: 59.52 ± 7.21% vs 59.79 ± 6.10% and Experiment 2: 68.88 ± 4.82 vs 74.41 ± 5.89%) and blastocyst (Experiment 1: 29.28 ± 4.14% vs 23.15 ± 2.96% and Experiment 2: 21.11 ± 3.28% vs 21.02 ± 6.08%) rates were similar between CC and GC (Experiments 1 and 2, respectively). Post-transfer embryo development revealed that pregnancy (CC: 24.27 ± 9.70% vs GC: 26.31 ± 7.23%) and calving (23.68% vs 33.33%) rates and fetal growth were not affected by the presence of cytoplasmic granules. Our results demonstrated that oocytes with granular cytoplasm present equivalent efficiency for IVF and calf production compared with homogenous cytoplasm oocytes. This could be observed through similar cleavage, blastocyst rates, and fetal growth development. In addition to differences in oocyte gene expression related to oocyte quality, it seems not to affect oocyte developmental competence.

Our objective was to study whether serum anti-Müllerian hormone (AMH) concentrations were associated with embryo morphokinetic events. This retrospective cohort study was performed in a private university-affiliated in vitro fertilization centre between March 2019 and December 2020 and included 902 oocytes cultured in a time-lapse imaging incubator, obtained from 114 intracytoplasmic sperm injection cycles performed. The relationship between AMH concentrations and morphokinetic events was investigated by considering the clustering of data (multiple embryos/patient). Evaluated kinetic markers were time to pronuclei appearance (tPNa) and fading (tPNf), time to two (t2), three (t3), four (t4), five (t5), six (t6), seven (t7), and eight cells (t8), (tSB) and time to the start of blastulation (tSB) and to blastulation (tB). Significant inverse relationships were observed between serum AMH concentrations and tPNf, t3, t4, t5, t6, t7, t8, and tB. The AMH was positively correlated with the KIDScore and implantation rate. Increased serum AMH concentrations correlated with faster embryo development. The clinical implications of this effect on embryo development warrant further investigation.

Although the role of myo-inositol (MYO) in promoting the oocyte quality of PCOS patients has been documented in human studies; the cellular effects of this supplement on oocytes have not been directly examined due to ethical limitations. In the first phase of this study, MYO dosimetry was carried out simultaneously with the PCOS model development. An effective dose was obtained following the assessment of fasting insulin and testosterone levels using ELISA and ovarian morphology appraisal by histopathology. In the second phase, following the continuous administration of the effective dose of MYO and dehydroepiandrosterone (DHEA), cellular evaluation was performed. The quality of oocytes from superovulation was analyzed by examining maturity and normal morphology percentage using a stereomicroscope, intracellular reactive oxygen species (ROS) and glutathione (GSH) levels using fluorometry, and ATP count evaluation using ELISA. The results revealed that, among the four different MYO concentrations, the 0.36 mg/g dose compared with the DHEA group reduced testosterone levels and large atretic antral follicles (LAtAnF) diameter. This dose also increased the corpus luteum count and the granulosa:theca (G/T)layer thickness ratio in antral follicles. Furthermore, this dose increased mature oocytes and normal morphology percentage, ATP count, and GSH levels; however, it decreased ROS levels in mature oocytes. Our findings provide the grounds for further cellular and molecular studies on the PCOS mouse model, suggesting that the improvement in mitochondrial function and its antioxidant properties is probably one of the mechanisms by which MYO increases oocyte quality.

Increasing evidence has demonstrated that obesity impairs female fertility and negatively affects human reproductive outcome following medically assisted reproduction (MAR) treatment. In the United States, 36.5% of women of reproductive age are obese. Obesity results not only in metabolic disorders including type II diabetes and cardiovascular disease, but might also be responsible for chronic inflammation and oxidative stress. Several studies have demonstrated that inflammation and reactive oxygen species (ROS) in the ovary modify steroidogenesis and might induce anovulation, as well as affecting oocyte meiotic maturation, leading to impaired oocyte quality and embryo developmental competence. Although the adverse effect of female obesity on human reproduction has been an object of debate in the past, there is growing evidence showing a link between female obesity and increased risk of infertility. However, further studies need to clarify some gaps in knowledge. We reviewed the recent evidence on the association between female obesity and infertility. In particular, we highlight the association between fat distribution and reproductive outcome, and how the inflammation and oxidative stress mechanisms might reduce ovarian function and oocyte quality. Finally, we evaluate the connection between female obesity and endometrial receptivity.

Polycystic ovary syndrome (PCOS) is a condition that affects fertility. There are two types of PCOS; the normal/lean type and overweight/obese type. The aim of this study was to assess baseline characteristics, ovarian response, quality of oocytes, embryos, pregnancy, implantation and live birth rates in normal/lean and overweight/obese patients with PCOS undergoing ICSI compared with patients without PCOS. This retrospective case–control analytical study included 38 normal/lean and 17 overweight/obese patients with PCOS, and 98 normal/lean and 17 overweight/obese patients without PCOS. Parameters were observed based on baseline characteristics, ovarian response to dosage and duration of gonadotropin administered, number of oocytes, matured oocytes, fertilization rate, embryo quality and development, pregnancy, implantation and live birth rates. Basal serum luteinizing hormone in normal/lean PCOS was significantly higher compared with non-PCOS groups. Total dosage of gonadotropin used was significantly lower in normal/lean PCOS compared with other groups. End estradiol levels in normal/lean PCOS was significantly higher compared with the non-PCOS groups. Number of follicles, retrieved oocytes and matured oocytes were significantly higher in PCOS groups compared with the non-PCOS groups. However, there were no differences in fertilized oocytes, cleavage, number of top-quality embryos, pregnancy, implantation, and live birth rates among groups. This present study suggests that normal/lean PCOS requires lower gonadotropin dosages and that patients with PCOS have more follicles and oocytes compared with patients without PCOS, however the number of fertilized oocytes and embryos from patients with PCOS were the same as those from patients without PCOS and suggested that the quality of retrieved oocytes in PCOS might be compromised.

Alcohol consumption has long been shown to affect both fetal health and pregnancy. In this study, antral follicle count, maturation level of oocytes including morphological assessment and number of metaphase I (MI), metaphase II (MII) and germinal vesicle (GV) stage oocytes obtained from young women (age < 30 years old) with or without alcohol consumption were investigated. In total, 20 healthy women who were social drinkers and 36 healthy women who do not consume alcohol were involved in this study. Women in both study and control groups were undergoing controlled ovarian stimulation. The antral follicle count and the number and quality of the oocytes retrieved were evaluated and recorded. In total, 635 antral follicles, 1098 follicles and 1014 oocytes with 820 MII, 72 MI and 78 GV stage oocytes were collected from the social drinkers. In the control group, 628 antral follicles, 1136 follicles and 1085 oocytes with 838 MII, 93 MI and 102 GV stage oocytes were evaluated. The results of this study showed that the antral follicle count was very similar in both groups. The number of oocytes and MII stage oocytes was slightly higher in the control group, although it was not a significant difference. This study showed that although the consumption of alcohol may have adverse effects post-implantation, it may not have a solid effect during oogenesis in young women. The results of this study are especially important in clinical settings as some women who are social drinkers undergo in vitro fertilization treatments.

This study aimed to evaluate the relationship between antral follicular count (AFC) and ovarian volume (OV), preantral follicular population and survival, meiotic progression and ultrastructure of cumulus–oocyte complexes (COCs) after in vitro maturation. In experiment 1, the relationship between AFC and preantral follicle population and survival was evaluated by classical histology. In experiment 2, the relationship among AFC, OV, ability of oocytes to resume meiosis and ultrastructure of in vitro matured bovine COCs was studied. A positive correlation (P < 0.05) between AFC and the numbers of healthy primordial, degenerate and total follicles was observed, as well as with healthy secondary follicles and total follicles. The numbers of grades I and II oocytes in ovaries of high AFC class were higher compared with those with intermediate or lower AFC. After in vitro maturation, COCs from ovaries of high AFC had a higher percentage of oocytes in metaphase II compared with those of intermediate and low AFC (P < 0.0001). Ovaries of intermediate AFC had a higher percentage of oocytes in metaphase II compared with ovaries with low AFC (P < 0.0001). The proportion of oocytes in metaphase I, telophase I and anaphase I in COCs from ovaries of intermediate AFC (26.04%) was higher (P < 0.05) compared with that seen in COCs of ovaries with high (8.55%) and low (14.15%) AFC. No differences in the ultrastructure of oocytes were seen. In conclusion, after in vitro maturation, cow ovaries with high AFC have higher numbers of oocytes that reach in metaphase II (MII), but they also have higher numbers of degenerated primordial and primary follicles.

Infertility is the most common issue in the field of reproductive medicine. Many factors affect fertility status, including life-style choices such as cigarette smoking or alcohol use. The aim of this study was to investigate the effects of cigarette smoking on oocyte quality as well the quantity in young fertile women. In total, 56 young fertile women who were undergoing oocyte donation programmes were included in this study. The effects of cigarette smoking on antral follicle count, number of follicles and oocytes retrieved and morphology were assessed by an expert embryologist. The results of this study showed that cigarette smoking did not have a significant effect on the follicle count or the number of oocytes retrieved from young and fertile women. However, a significant difference was observed in the morphological assessment. In conclusion, although cigarette smoking does not seem to affect oocyte development, it had an effect on cytoplasmic anomalies and therefore may lower pregnancy chance. Therefore, it is crucial to give proper counselling to patients who are trying to become pregnant both naturally and by in vitro fertilization.

Activated pERK1/2 and pAKT are key players in supporting cell survival and proliferation pathways. Translocation of pERK1/2 into the nucleus, where it interacts with transcription factors and DNA itself, is instrumental in exerting an anti-apoptotic effect. In this study, pAKT levels, pERK1/2 nuclear localization and DNA fragmentation index (DFI) in cumulus cells of single cumulus–oocyte complexes of patients undergoing in vitro fertilization programmes were evaluated and correlated with the clinical outcome of the related embryos. For a positive clinical outcome of blastocyst development, pERK1/2 nuclear localization and DFI value had a significant inverse relationship, whereas the former and the intracellular accumulation of pAKT had a significant direct relationship. This relationship was not observed for the negative clinical outcome of the arrested embryos. Moreover, intracellular accumulation of pAKT and DFI value had a significant inverse relationship in all samples examined. The obtained data suggest that the intranuclear relocation of pERK1/2, along with an enhanced intracellular accumulation of pAKT, may exert a survival effect and increase cell viability, therefore providing a novel marker tool to choose the best oocyte to be fertilized and submitted to an intracytoplasmic sperm injection cycle.

The aim of this study was to investigate if there is an adverse effect of multiple controlled ovarian stimulation (COS) on the maturity of oocytes (MI and MII), fertilization rate, embryo developmental qualities and clinical pregnancy rates in donation cycles. In total, 65 patients undergoing oocyte donation cycles multiple times were included in this study. Patients were grouped as group A that consisted of donors with ≤2 stimulation cycles while B consisted of donors with ≥3 stimulation cycles; and group C included donors who had ≤15 oocytes, while group D had donors with ≥16 oocytes. Numbers of oocytes obtained, MI and MII oocytes, fertilization, embryo quality and clinical pregnancy outcomes were compared. Significant statistical differences were observed in total number of oocytes obtained, maturity of oocytes (MI and MII), fertilization rate, embryo qualities and clinical pregnancy outcomes of donors in groups A–D. Donors with ≤2 ovarian stimulation cycles had lower numbers of immature oocytes than donors with three or more stimulation cycles. However, donors with ≥3 stimulation cycles had higher numbers of mature oocytes, zygotes, with better day 3 embryo qualities and higher clinical pregnancy rates than donors with ≤2 stimulation cycles. Repeated COS does not seem to have any adverse effect on ovarian response to higher dose of artificial gonadotropin, as quality of oocytes collected and their embryological developmental potential were not affected by the number of successive stimulation cycles. The effect of multiple COS on the health of the oocyte donor needs to be assessed for future purpose.

Oocyte capacity is relevant in understanding decreasing female fertility and in the use of assisted reproductive technologies in human and farm animals. Mitochondria are important to the development of a functionally good oocyte and the oocyte mtDNA copy number has been introduced as a useful parameter for prediction of oocyte competence. The aim of this study was to investigate: (i) if the oocyte donor has an influence on its oocyte's mtDNA copy number; and (ii) the relation between oocyte size and mtDNA copy number using pre- and postpubertal pig oocytes. Cumulus–oocyte complexes were collected from individual donor pigs. The oocytes were allocated into different size-groups, snap-frozen and single-oocyte mtDNA copy number was estimated by quantitative real-time PCR using the genes ND1 and COX1. Results showed that mean mtDNA copy number in oocytes from any individual donor could be categorized as either ‘high’ (≥100,000) or ‘low’ (<100,000) with no difference in threshold between pre- and postpubertal oocytes. No linear correlation was detected between oocyte size and mtDNA copy number within pre- and postpubertal oocytes. This study demonstrates the importance of the oocyte donor in relation to oocyte mtDNA copy number, irrespectively of the donor's puberty status and the oocyte's growth stage. Observations from this study facilitate both further investigations of the importance of mtDNA copy number and the unravelling of relations between different mitochondrial parameters and oocyte competence.

The post-fertilisation developmental capacity of bovine oocytes recovered by ultrasound guided transvaginal follicular aspiration (ovum pick-up, OPU) is influenced by diet-induced changes in hormone and metabolite concentrations. The objectives of this experiment were first to determine whether post-prandial changes in hormone concentrations, induced by changing the frequency of feeding, influenced oocyte quality and second whether changes in plasma glucagon concentration were associated with oocyte quality. Using a 2 × 2 factorial design, Holstein heifers (six per treatment) were fed either fibre- or starch-based diets containing either 189 or 478 g starch/kg dry matter. The diets were offered in either two or four equal meals per day and supplied twice the maintenance energy requirement. Blood samples were obtained both at weekly intervals (three samples per heifer, collected before feeding) during the experiment and throughout an entire 24-h period (15 or 17 samples per heifer for twice or four times daily-fed heifers, respectively). Each heifer underwent six sessions of OPU (twice weekly) beginning 25 days after introduction of the diets. Oocyte quality was assessed by development to the blastocyst stage in synthetic oviductal fluid following in vitro fertilisation. Mean weekly plasma insulin concentrations did not differ between diets, but plasma glucagon concentrations were greatest when heifers were fed the starch-based diet twice daily compared with the other diets. When heifers were offered four meals per day, there were no meal-related changes in hormone concentrations. However, when heifers were offered two meals per day, plasma insulin concentration increased after feeding the starch-based, but not the fibre-based diet. Plasma glucagon concentration increased after meals when heifers were fed twice daily and the increase was substantially greater when the starch-based diet was fed. Treatments did not influence (overall mean with mean ± s.e.) ovarian follicle size distribution or oocyte recovery by OPU (6.2 ± 0.4 per heifer), the proportion of oocytes that cleaved following insemination (0.57 ± 0.030) or blastocyst yield (0.27 ± 0.027 of oocytes cleaved). In conclusion, by feeding diets differing in carbohydrate source at different frequencies of feeding, meal-related changes in plasma hormone profiles were altered significantly, but oocyte quality was not affected. Therefore effects of diet on oocyte quality appear not to be mediated by meal-related fluctuations in hormone concentrations.

The effect of providing algal food to female Crassostrea gigas broodstock sampled at a favourable time of year was investigated using pre-defined indices of oocyte quality and subsequent larval and post-larval performances. Broodstock were collected in the Aber Benoît estuary (Brittany, France) at the end of April 2002 and were divided into two groups, a starved control (S, 1 µm – filtered seawater) and a fed group (F, ad libidum algal mixture of Isochrysisgalbana clone T-Iso and Chaetoceros calcitrans), maintained under these conditions for six weeks prior to fertilizations. For each conditioning type, two batches of larvae and post-larvae were reared from two identified females. Quality criteria were defined in terms of predictors (oocyte lipid contents, mature oocyte diameters, ovarian maturity and presence/absence of atresia) and validators (larval growth, algal consumption and time to settlement, and post-larval growth). Each female was considered as a treatment, and parametric and non-parametric ANOVAs were performed, where appropriate, on predictors and validators between each treatment. In both conditions, a surplus of oocytes was produced, in relation to expected market conditions. No effect of the conditioning treatment was detected either on oocyte quality predictors or on subsequent validators. It is likely that winter reserve accumulation is more important than trophic conditioning for successful gametogenesis in the productive Aber Benoît environment. Given the considerable cost of abundant feeding during the conditioning of broodstock collected at the end of winter and destined for gamete stripping (the prevalent practice in France), we suggest that feeding be minimal or suppressed altogether when the condition index is favourable.

Controlled ovarian stimulation was induced in 19 women for in vitro fertilisation/embryo transfer. After ovum pick-up, haptoglobin titres were determined by ELISA in sera and homologous follicular fluids. The haptoglobin phenotype of each subject was assessed and the penetration of the protein forms through the blood-follicle barrier was predicted on the basis of their molecular weight. The penetration threshold compatible with the barrier integrity was calculated as 92%, 73% and 57% of the blood level of phenotypes Hpt 1-1, Hpt 1-2 and Hpt 2-2 respectively. Penetration values comparable/lower or higher than threshold were found associated with 46 of 49 and 3 of 49 fertilised oocytes, respectively. Complexes of haptoglobin with apolipoprotein A-1 were isolated from follicular fluids by affinity chromatography with haemoglobin. The haptoglobin β chain, after Western blotting and incubation with apolipoprotein A-1, was found to be involved in the protein–protein interaction as detected by anti-apolipoprotein A-1 antibodies. Complexes from separate fluids were analysed by electrophoresis and densitometry: the plain β chain/apolipoprotein A-1 stoichiometric ratio was 0.75 and 1.40 in fluids associated with fertilised and unfertilised oocytes respectively. The results suggest that haptoglobin transport in the follicle depends on the integrity of the blood–follicle barrier and might be associated with oocyte quality, possibly by interfering with the role of apoliprotein A-1 in cholesterol or vitamin E exchange between high-density lipoproteins and granulosa cells.