Correction: Potential role of tea extract in oocyte development

Correction for ‘Potential role of tea extract in oocyte development’ by Lei Zhao et al., Food Funct., 2021, 12, 10311–10323, DOI: 10.1039/D1FO01725J.

Equine Chorionic Gonadotropin as an Effective FSH Replacement for In Vitro Ovine Follicle and Oocyte Development

The use of assisted reproductive technologies (ART) still requires strategies through which to maximize individual fertility chances. In vitro folliculogenesis (ivF) may represent a valid option to convey the large source of immature oocytes in ART. Several efforts have been made to set up ivF cultural protocols in medium-sized mammals, starting with the identification of the most suitable gonadotropic stimulus. In this study, Equine Chorionic Gonadotropin (eCG) is proposed as an alternative to Follicle Stimulating Hormone (FSH) based on its long superovulation use, trans-species validation, long half-life, and low costs. The use of 3D ivF on single-ovine preantral (PA) follicles allowed us to compare the hormonal effects and to validate their influence under two different cultural conditions. The use of eCG helped to stimulate the in vitro growth of ovine PA follicles by maximizing its influence under FBS-free medium. Higher performance of follicular growth, antrum formation, steroidogenic activity and gap junction marker expression were recorded. In addition, eCG, promoted a positive effect on the germinal compartment, leading to a higher incidence of meiotic competent oocytes. These findings should help to widen the use of eCG to ivF as a valid and largely available hormonal support enabling a synchronized in vitro follicle and oocyte development.

Raman Spectrum of Follicular Fluid: a Potential Biomarker for Oocyte Developmental Competence in Polycystic Ovary Syndrome

Background: Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in reproductive women where abnormal folliculogenesis is considered as a common characteristic. Our aim is to evaluate the potential of follicular fluid (FF) Raman spectra to predict oocyte development and pregnancy outcome, so as to prioritize the best promising oocyte for implantation, reducing both physiological and economical burdens of PCOS patients. In addition, the altered metabolic profiles will be identified to explore the aetiology and pathobiology of PCOS. Methods: In this study, follicular fluid samples obtained from 150 PCOS and 150 non-PCOS women were measured with Raman spectroscopy. Individual Raman spectrum was analyzed to find biologic components contributing to the occurrence of PCOS. More importantly, the Raman spectra of follicular fluid from the 150 PCOS patients were analyzed via machine-learning algorithms to evaluate their predictive value for oocyte development potential and clinical pregnancy. Results: Mean-centered Raman spectra and principal component analysis showed global differences in the footprints of follicular fluid between PCOS and non-PCOS women. Two Raman zones (993-1,165 cm-1 and 1,439-1,678cm-1) were identified for describing the largest variances between the two groups, with the former higher and the latter lower in PCOS FF. The tentative assignments of corresponding Raman bands included phenylalanine and β -carotene. Moreover, it was found that FF, in which oocytes would develop into high-quality blastocysts and obtain high clinical pregnancy rate, were detected with lower quantification of the integration at 993-1,165 cm-1 and higher quantification of the integration at 1,439-1,678 cm-1 in PCOS. In addition, based on Raman spectra of PCOS FF, the machine-learning algorithms via the fully connected artificial neural network (ANN) achieved the overall accuracies of 90% and 74% in correctly assigning oocyte developmental potential and clinical pregnancy, respectively. Conclusions: The study suggests that the PCOS displays unique metabolic profiles in follicular fluid which could be detected by Raman spectroscopy. Specific bands in Raman spectra have the biomarker potential to predict the oocyte development and pregnancy outcome for PCOS patients. Importantly, these data may provide some valuable biochemical information and metabolic signatures that will help us to understand the abnormal follicular development in PCOS.

Transcriptomic comparison of ovarian granulosa cells between adult sheep and prepubertal lambs

Background The oocyte development ability of prepubertal animals is significantly lower than that of adult animals. Granulosa cells (GCs) have an important function on regulation of follicular and oocyte development. Therefore, analysis of GCs characteristics can be used to explore the developmental mechanism of follicles and oocytes. Results In order to understand the possible reasons for the differences in follicles and oocytes development between lambs and adult sheep, we utilized high-throughput sequencing technique to analyze the transcriptome of GCs from follicle-stimulating hormone (FSH) superstimulated adult ewes and prepubertal lambs. Adult ewes were stimulated with FSH for 3 days (group A) and lambs were FSH-stimulated for 2 days (group B) or 3 days (group C). Transcriptome analysis of GCs showed that there were 405 and 159 differentially expressed genes from A vs. B and A vs. C, respectively. The results indicated that prolonging the FSH-stimulation of lambs made the GC state of lambs more similar to the adult sheep, but there were still a large number of differentially expressed genes between adult sheep and lambs. Further analysis showed that many differently expressed genes were implicated in cell proliferation and apoptosis, oocyte development and follicular ovulation. Cellular examination demonstrated that fatty acid binding protein 4 (FABP4), which was highly expressed in lamb GCs, had a potential of promoting cell apoptosis. Cytoplasmic phospholipase A2 (PLA2G4A), which was expressed lowly in lamb GCs, may be responsible for reduced synthesis of prostaglandins in cells and impaired follicle/oocyte development. In contrast, glutathione S-transferase β-1 (GSTT2B) and forkhead boxO6 (FOXO6) had no apparent effect on the proliferation and apoptosis of GCs.