Zygote最新文献

This study aimed to investigate the relationship between oocyte meiotic and developmental competences and antral follicle diameter on random days of estrous in naturally cycling zebu females (Nellore - a tropical Bos indicus breed). Immature oocytes recovered from early antral follicles (diameter of 0.5 to 2 mm) exhibited a higher percentage of intact transzonal projections, but lower viability, smaller diameter and a higher proportion of chromatin decondensation when compared to those recovered from mid- (diameter > 2 to 6 mm) and late antral follicles (diameter > 6 mm), demonstrating that oocytes recovered from early antral follicles lack meiotic and developmental competence. Immature oocytes recovered from mid- or late antral follicles were homogeneous in terms of morphology and size, in addition to exhibiting a high proportion of a pattern of chromatin configuration compatible with high developmental competence, which may help explain the better oocyte quality and improved performance of zebu donors in IVP programs. At the end of the in vitro maturation culture, the percentage of oocytes that completed meiotic maturation was higher when they were recovered from late antral follicles compared to mid antral follicles, although the rate of embryonic development to the blastocyst stage was similar. Our results demonstrated a relationship between the acquisition of competences during the final stages of oocyte growth and morphofunctional events, including the chromatin structure remodeling, but further research is needed to better characterize the functional differences in ovarian physiology between bovine breeds that may impact the oocyte developmental potential.

The objective of this study was to compare embryonic morphokinetic parameters and clinical outcomes of two controlled ovarian stimulation (COS) protocols in women of advanced maternal age (AMA): Pergoveris (r-hFSH:r-hLH, 2:1 ratio) versus r-hFSH monotherapy (GONAL-f). This retrospective, non-interventional descriptive study was conducted at a private university-affiliated IVF center and included 136 ICSI cycles performed in AMA patients between March 2019 and May 2020. Patients were grouped by COS protocol (GONAL-f, n = 64; Pergoveris, n = 72), and embryo morphokinetics and ICSI outcomes were extracted from the clinic's database; the main outcome was time to complete blastulation (tB, hours). Embryos from the Pergoveris group reached tB earlier than those from the GONAL-f group (mean 109.3 h vs 112.6 h), and all morphokinetic milestones occurred sooner with Pergoveris, alongside lower multinucleation rates at the 2-cell and 4-cell stages. Although blastocyst development was higher in the GONAL-f group, Pergoveris was associated with higher oocyte yield and maturity, higher implantation, clinical and ongoing pregnancy rates, and lower miscarriage and OHSS rates; Pergoveris cycles also required higher gonadotropin doses and longer stimulation. Overall, embryos from the r-hFSH:r-hLH group exhibited faster morphokinetic timings and improved implantation and pregnancy outcomes, and prospective studies are warranted to confirm these observations.

This study aimed to evaluate the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and inactivated virus vaccination on intracytoplasmic sperm injection (ICSI) outcomes in infertile couples. A retrospective case-control study was conducted at the Royan Institute from August 2020 to March 2022. The study included 90 couples in the COVID-19 infection phase and 31 in the vaccination phase. A total of 30 infected but unvaccinated couples were compared to a control group of 60 couples with no COVID-19 infection or vaccination history. Additionally, 31 couples underwent treatment before and after receiving the Sinopharm inactivated vaccine. Key variables analysed included sperm parameters (concentration, motility, progressive motility and morphology), ovarian parameters (antral follicle count, oocyte retrieval), embryological outcomes and pregnancy outcomes. SARS-CoV-2 infection significantly reduced sperm motility (P = 0.02) and progressive motility (P = 0.01) compared to controls. Sperm concentration and morphology showed non-significant declines. Post-vaccination analysis revealed similar but statistically insignificant changes in sperm parameters. Ovarian stimulation parameters and embryological outcomes remained unaffected by both infection and vaccination. Although biochemical, clinical pregnancy and live birth rates were lower among the infected group, these differences did not reach statistical significance (p = 0.16, 0.08 and 0.09). SARS-CoV-2 infection has been associated with impaired sperm progressive motility, which may negatively influence ICSI outcomes. In contrast, vaccination with an inactivated virus does not appear to impact fertility outcomes. These findings provide crucial guidance for physicians and infertile couples managing treatments during and after the pandemic, suggesting the need for extended recovery periods before ART procedures following COVID-19 infection.

Purpose: To compare the effect of two different assisted hatching laser protocols thinning assisted hatching laser (TAH) vs drilling of assisted hatching laser (DAH) and non-assisted hatching control group (NAC) on clinical pregnancy and live birth rates in frozen thawed cleavage stage embryo transfer cycles.

Patients and methods: This study included 310 infertile patients who underwent frozen embryo transfer (FET) cycles from 2021 to 2022 at the ART Unit of the Medical Point Hospital of Izmir University of Economics, Izmir. Patients included in the study were those between 20 and 40 years of age, who had undergone frozen-thawed embryo transfer after 'freeze-all' protocols. The exclusion criteria were azoospermia and degenerated embryos. In TAH, laser thinning was performed by making 4-5 shots at a depth of 50% of the thickness of the zona pellucida (ZP). In DAH, the laser opening was made from the outer part of the ZP to the inner part. In the last group in NAC, assisted hatching was not performed. Clinical pregnancy and ongoing pregnancy rates were compared between the TAH, DAH and NAC cycles.

Results: There was no difference in terms of the age of the woman, the BMI and the sperm parameters in the three groups. There were no statistical differences between the groups in terms of the number of oocytes, embryos and the quality of the transferred embryos. Clinical pregnancy in thinning assisted hatching laser (TAH), drilling of assisted hatching laser (DAH), non-assisted hatching control group (NAC) cycles (38% vs 39% vs 45% p = 0.842, respectively.), ongoing pregnancy (34% vs 32% vs 39%; p = 0.670, respectively.) and live birth rates (34% vs 29% vs 35,4%; p = 0.586, respectively) were similar in three groups.

Conclusion: In conclusion, no significant differences were found between the TAH, DAH and NAC groups in terms of ART outcomes.

Extracellular vesicles (EVs) are implicated in various functions within the complex mechanisms of intercellular communication. There are several subpopulations of EVs, including apoptotic bodies, microvesicles and exosomes. These nanovesicles are capable of transferring functional proteins and genetic information to alter the phenotype and function of recipient cells. In animal reproduction, numerous studies have demonstrated that EVs are actively involved in the regulation of different physiological events, modulating a variety of processes such as follicular development, spermatogenesis, oocyte maturation, fertilization and embryo development, with results indicating improved gamete quality, embryo development and cryotolerance. Additionally, EVs show therapeutic potential in restoring reproductive function and supporting maternal-embryonic communication in both domestic and wild species. Therefore, the present review aimed to describe the main studies conducted using EVs in the field of animal reproduction, highlighting their biological relevance, experimental applications and future prospects for clinical implementation in assisted reproductive technologies.

Intracytoplasmic sperm injection (ICSI) is a widely used assisted reproduction technique, but in cattle it faces major challenges due to inefficient oocyte activation after sperm microinjection. This study investigated different oocyte activation strategies and assessed the potential role of reducing agents glutathione (GSH), cysteamine (Cys) and dithiobutylamine (DTBA) to improve sperm head decondensation and embryo development following Piezo-ICSI. Haploid parthenogenetic activation using different ethanol concentrations (1%, 3%, 7% and 10%) failed to yield blastocysts, while diploid activation with ethanol or ionomycin combined with inhibitors significantly improved cleavage (43-55%) and blastocyst rates (14-27%), respectively. However, applying two ethanol pulses was detrimental, reducing both cleavage and blastocysts likely due to toxic overexposure. Sperm head decondensation compounds in Piezo-ICSI showed a high percentage of inactivated oocytes (75% GSH, 55% Cys and 40% DTBA). The highest male pronuclear formation rates were observed in the control without sperm head decondensation (21%) and with DTBA treatment (10%). Despite this, the treatment with Cys resulted in higher developmental potential to the blastocyst stage (22%) comparable to the control (24%). These data suggest that the inclusion of sperm head decondensing agents could represent a promising new strategy for enhancing the early in vitro development of ICSI-generated embryos. However, for this purpose, careful optimization of the concentration and incubation time of these decondensing compounds is essential.

Centromeres are chromosomal loci essential for the correct segregation of genetic material during cell division. Defects in centromere function can lead to aneuploidy and cancer. During early embryonic development in mammals, prior to the first cell division, male and female genomes are separated in pronuclei located at the centre of the zygote. Parental chromatin clusters at the interface between the two pronuclei and this clustering step is critical to avoid aneuploidy in human and bovine zygotes. Yet, despite their essential function in chromosome segregation, the position and spatial organization of centromeres during the first cell cycle in mammals is mostly unknown. Previous studies conducted in bovine embryos derived from in vitro fertilization (IVF) showed that cell cycle progression impacts on the success rate of blastocyst formation. Specifically, embryos that entered earliest into S-phase or the earliest cleaving embryos were more likely to develop into blastocysts. To determine the precise timing of these events we performed a detailed characterization of key phases of the first cell cycle in bovine zygotes derived from IVF. In parallel we examined the spatial positioning of centromeres. We identify 20 h post insemination (hpi) as the timepoint when male and female pronuclei are juxtaposed and are completing S-phase. At this timepoint, we show that centromeres are positioned distal to the pronuclear interface and use super resolution microscopy to demonstrate extensive centromere clustering into chromocentres. Our results identify distinct nuclear features observed at 20 hpi, which may serve as cell cycle markers in determining successful bovine IVF.

Kisspeptin, encoded by Kiss1 gene, regulates reproduction via the hypothalamic-pituitary-gonadal axis. While kisspeptin treatment promotes follicular development in Tan sheep, its direct action on ovarian granulosa cells remains unclear. For this, we first detected the expression of Kiss1 and its receptor Kiss1r in primary ovarian granulosa cells of Tan sheep. Second, the effect of kisspeptin on steroid hormone secretion, proliferation and apoptosis of ovarian granulosa cells was investigated. Third, the signaling pathway of kisspeptin regulating steroid hormone secretion was revealed by western bolting in ovarian granulosa cells. The results showed that the Kiss1 and Kiss1r genes were present in ovarian granulosa cells of Tan-sheep, and 500 nM dose of kisspeptin significantly stimulated steroids hormone secretion (P < 0.05), and up-regulated StAR, HSD17B2, CPY19A1, FSHR, LHR, ERβ, PGR and p-ERK1/2 proteins expression (P < 0.05). Moreover, this treatment significantly promoted cell proliferation and increased the proportion of cells in S phase (P < 0.05), and significantly suppressed granulosa cell apoptosis (P < 0.05). Additionally, the stimulatory effects of kisspeptin on estradiol and progesterone secretion were blocked by inhibitors of the Mitogen-activated Protein Kinase (MAPK) signaling pathway (including PKA inhibitor, PLC inhibitor, PKC inhibitor, and Ca²⁺inhibitor). Western blot analysis confirmed that kisspeptin regulates steroid hormone secretion primarily through the MAPK-ERK signaling pathway. Our results demonstrate that kisspeptin can directly act on ovarian granulosa cells to promote steroidogenesis, proliferation, and inhibit apoptosis, providing a foundational basis for developing novel kisspeptin-mediated techniques to regulate reproduction in Tan sheep.

This work investigated the effect of zinc oxide nanoparticles functionalized with curcumin (ZnO_(np)+CUR) supplementation during the in vitro maturation (IVM) of bovine oocytes on the in vitro embryo production and the cellular antioxidant response. A total of 1,625 cumulus-oocyte complexes (COCs) were cultured in the maturation medium in the absence (0 µM - control) or presence of different concentrations of ZnO_(np)+CUR (3 µM, 6 µM or 12 µM). After IVM, COCs were destined either to 1) in vitro embryo production or 2) analysis of reactive oxygen species production, superoxide dismutase (SOD) activity, catalase (CAT) activity and total antioxidant capacity (FRAP). The results demonstrated that the addition of 6 and 12 µM ZnO_(np)+CUR during in vitro maturation showed a higher rate of blastocyst production when compared to the control (p < 0.05). However, only 12 µM ZnO_(np)+CUR treatment showed higher rates of embryo production when compared to 3µM ZnO_(np)+CUR treatment. Supplementation of IVM medium with 6 µM ZnO_(np)+CUR reduced ROS production (p < 0.05) compared to control and 12 µM ZnO_(np)+CUR treatments. Also, the treatment containing ZnO_(np)+CUR at 12 µM had lower SOD activity after IVM than control treatment. In conclusion, the best outcome for in vitro embryo production was obtained when 6 and 12 µM ZnO_(np)+CUR was added during IVM of bovine oocytes. However, this improvement in in vitro embryo production was not associated with either the reduction of ROS production or SOD and CAT activities.