Zygote最新文献

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.

Aneuploidy in oocytes is a leading cause of implantation failure, miscarriage and congenital disorders. During meiosis, proper timing of chromosome segregation is regulated by the spindle assembly checkpoint (SAC) and the anaphase-promoting complex/cyclosome (APC/C). However, how pharmacological manipulation of these regulatory pathways affects aneuploidy remains incompletely understood. In this study, we investigated whether SAC inhibition by reversine induces aneuploidy in mouse oocytes and whether partial inhibition of APC/C by proTAME can alleviate these errors. Germinal vesicle (GV) oocytes were matured in vitro in the presence of various concentrations of reversine. To optimize the timing of treatment, oocytes were exposed to reversine for 0, 3, 5 or 7 h, followed by culture with or without proTAME. A proTAME-only group (2.5 nM) was also included. Chromosome spreads were analyzed at the metaphase II (MII) stage to determine aneuploidy rates. Reversine (5 nM) yielded an MII maturation rate of 80.5% but induced a high aneuploidy rate of 77.0%. Sequential treatment with 2.5 nM proTAME significantly reduced aneuploidy to 33.3%. In contrast, proTAME alone led to 79.0% aneuploidy, suggesting its effect is contingent upon prior SAC disruption. These results indicate that reversine compromises chromosomal integrity, while appropriately timed, low-dose proTAME can partially rescue segregation errors. Our findings underscore the potential of pharmacologically regulating APC/C activity to reduce aneuploidy and enhance oocyte quality, offering new avenues for improving outcomes in assisted reproductive technologies.

The reproductive efficiency of dairy cows decreases significantly in hot climates. Exposure to heat stress causes damage to different stages of the reproductive cycle including a decrease in the quality of oocytes. Antioxidant supplementation has been introduced as one of the main approaches to alleviate the effects of free radical damage associated with heat stress. Gamma-oryzanol (ORY), a component of rice bran oil, is introduced as a novel antioxidant. As a supplement of culture media for maturation, the effect of ORY on the development of heat-shocked bovine cumulus-oocyte complexes was evaluated in this study. At the end of maturation in vitro using the heat-shock model, a higher proportion of metaphase II oocytes (0.78 ± 0.03 vs 0.42 ± 0.03) and lower metaphase I and germinal vesicle breakdown (0.10 ± 0.02 vs 0.38 ± 0.03) were recorded for the treated group (N = 205) in comparison with the control (N = 203) (P < 0.05). Moreover, the treatment exerted upregulation of NRF2, SOD, CAT and GPX transcripts in matured oocytes and GPX in CCs, along with a considerable increase in the cleavage (0.52 ± 0.04 vs 0.33 ± 0.03) and total blastocyst rates (0.30 ± 0.03 vs 0.14 ± 0.02) (P < 0.05). These results showed that ORY increased the mRNA expression of the transcripts associated with antioxidant enzymes and enhanced the developmental potential of heat-shocked bovine oocytes and warranted further studies to explore this antioxidant's influence on improving dairy cattle's reproductive efficiency during heat stress.

Circadian rhythms are intrinsic, endogenously generated cycles that regulate various physiological processes, including reproductive functions. These rhythms are orchestrated by a network of core clock genes and are influenced by external environmental cues, primarily the light-dark cycle. Disruptions in circadian rhythms can have profound effects on fertility in both males and females, impacting processes such as the estrous cycle, ovulation, sperm production, implantation and pregnancy maintenance. This review comprehensively explores the molecular mechanisms underlying circadian rhythms and their influence on reproductive health, integrating evidence from both animal models and human studies. We delve into the intricate interplay between circadian genes, hormonal regulation and environmental factors, underscoring the critical importance of circadian integrity for optimal reproductive outcomes. The potential therapeutic implications of maintaining circadian rhythms are also discussed, highlighting novel avenues for enhancing reproductive health.

Aim: High oestradiol levels during in vitro fertilization (IVF) fresh cycles have been linked to adverse obstetric outcomes, yet whether this is due to endometrial or oocyte effects remains unclear. Investigating subsequent frozen embryo transfer (FET) cycles can help clarify the origins of these effects. This study aimed to evaluate obstetric outcomes and placental histology in FET cycles for patients with elevated serum oestradiol levels during the ovarian stimulation cycle in which the embryos were created.

Methods: A single centre retrospective cohort study of live singleton deliveries after IVF with programmed FET from 2009 to 2017. High oestradiol during ovarian stimulation was defined as ≥10,000 pmol/L. We compared obstetric outcomes and placental findings between pregnancies with high oestradiol levels in the preceding ovarian stimulation cycle and a control group.

Results: We analyzed 114 deliveries in the high oestradiol group and 194 in the control group. Baseline demographics were comparable between groups. No significant differences were observed in obstetric outcomes, including low birth weight, preeclampsia and preterm delivery. The placental macroscopic and histopathological findings did not significantly differ between the groups as well.

Conclusion: High oestradiol during the ovarian stimulation cycle used to create embryos is not associated with adverse obstetric outcomes or placental pathologies in pregnancies following FET. This is consistent with an endometrial effect of high oestradiol and thus support the practice of a freeze all approach in high oestradiol cycles.

This study aimed to investigate the efficacy of cell-free DNA (CF-DNA) in the spent cleavage and blastocyst medium versus blastomere biopsy for sex identification using short tandem repeat (STR) markers for the first time. In total, 39 samples of spent culture medium (SCM) from six couples were collected of which 28 samples were CF-DNA from blastocoel fluid + SCM (day 5) and 11 samples from SCM alone (day 3). The frequencies of allele dropout (ADO), fail rate and informativity markers were considered. The relationship between the morphology of embryos and ADO and the fail number of all markers was investigated. Sex identification rate between CF-DNA isolated from culture medium and fluorescence in situ hybridization (FISH) was then compared with measurement of Agreement Kappa (AK). The highest frequency of informative markers belonged to DXS6801 and HPRT. There was no relationship between the ADO number of all markers and embryo morphology. A significant difference was seen between embryo morphology and fail numbers. AK value between CF-DNA isolated from culture medium and FISH was 0.516, which is moderate. The ability of CF-DNA to detect the correct diagnosis of males and females showed that all values of specificity, sensitivity, positive predictive value, and negative predictive value were 100%. The presence of embryonic CF-DNA in the SCM on day 3 as well as blastocyst medium on day 5 using STR-based multiplex PCR is approximately consistent with FISH for sex identification. Advances in DNA extraction, amplification technique, and testing may allow for preimplantation genetic testing for aneuploidy (PGT-A) and monogenic/single-gene disorders (PGT-M) as a non-invasive approach without biopsy in the future either in sex determination or chromosomal abnormality.

In this study, we describe the ovarian structure and oogenesis up to the final maturation of oocytes of Hypancistrus seideli. A total of sixty females were used for gonadal analysis and subsequently submitted to light and scanning electron microscopy analyses. Four maturation stages were defined: immature, maturing, mature, and spawned. The oocytes were classified into four stages (I–IV), and the presence of atretic oocytes and post-ovulatory follicles was demonstrated. During oocyte development, changes were observed in color, size, and shape, as well as in the formation of the follicular complex. These results may support reproductive management in captivity, since the species has great commercial importance in the international ornamental fish market and lacks established reproductive protocols in aquaculture. To our knowledge, this is the first morphological characterization of oogenesis in this species, providing original and detailed data that may contribute to the development of captive breeding protocols and to reducing pressure on natural stocks.

This study aimed to evaluate the effects of acetyl-L-carnitine on follicle survival and growth, stromal cell density and extracellular matrix, as well as on the expression of mRNA for nuclear factor erythroid 2-related factor (NRF2), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and peroxiredoxin 6 (PRDX6) in cultured bovine ovarian cortical tissues. Ovarian fragments (3 × 3 × 1 mm) were cultured for 6 days in α-MEM⁺ alone or supplemented with 10, 50 or 100 μM acetyl-L-carnitine at 38.5°C with 5% CO₂ in humidified air. Before (non-cultured tissues) and after culture, the ovarian fragments were fixed in 4% paraformaldehyde for 12 h for histological analysis or stored at -80ºC for mRNA expression analysis of NRF2, SOD, CAT, PRDX6 and GPX1. The results showed that 100 μM acetyl-L-carnitine increased the percentages of morphologically normal follicles and stromal cell density in cultured ovarian tissues. On the other hand, acetyl-L-carnitine did not influence the percentage of collagen in ovarian tissue nor the expression of mRNAs for NRF2, SOD, CAT, PRDX6 and GPX1. In conclusion, 100 μM acetyl-L-carnitine increased follicle survival and stromal cell density in cultured bovine ovarian tissues but does not influence collagen fibre distribution or the expression of mRNAs for NRF2, SOD, CAT, PRDX6 and GPX1.