Spindle Morphology In Oocytes Research Articles

FGF2, LIF, and IGF-1 supplementation improves mouse oocyte in vitro maturation via increased glucose metabolism†.

Chemically defined oocyte maturation media supplemented with FGF2, LIF, and IGF-1 (FLI medium) enabled significantly improved oocyte quality in multiple farm animals, yet the molecular mechanisms behind such benefits were poorly defined. Here, we first demonstrated that FLI medium enhanced mouse oocyte quality assessed by blastocyst formation after in vitro fertilization and implantation and fetal development after embryo transfer. We then analyzed the glucose concentrations in the spent media; reactive oxygen species concentrations; mitochondrial membrane potential; spindle morphology in oocytes; and the abundance of transcripts of endothelial growth factor-like factors, cumulus expansion factors, and glucose metabolism-related genes in cumulus cells. We found that FLI medium enabled increased glucose metabolism through glycolysis, pentose phosphate pathway, and hexosamine biosynthetic pathway, as well as more active endothelial growth factor-like factor expressions in cumulus cells, resulting in improved cumulus cell expansion, decreased spindle abnormality, and overall improvement in oocyte quality. In addition, the activities of MAPK1/3, PI3K/AKT, JAK/STAT3, and mTOR signaling pathways in cumulus cells were assessed by the phosphorylation of MAPK1/3, AKT, STAT3, and mTOR downstream target RPS6KB1. We demonstrated that FLI medium promoted activations of all these signaling pathways at multiple different time points during in vitro maturation.

A new approach to evaluate the influence of advancing maternal age upon meiotic spindle morphology and developmental competence in human oocytes

The developmental competence of oocytes/embryos decreases with advancing maternal age, and meiotic errors gradually increase from when a woman reaches her late 30s. The evaluation of meiotic spndle morphology using a Polscope is an effective method for investigating the effect of maternal age. However, very little is known about the relationship between meiotic spindle morphology in oocytes and their developmental competence as maternal age advances.

Myeloperoxidase and activated macrophages have differing effects on oocyte spindle morphology

Myeloperoxidase and activated macrophages have differing effects on oocyte spindle morphology

Is oocyte meiotic spindle morphology associated with embryo ploidy? A prospective cohort study

To explore whether an association exists between oocyte meiotic spindle morphology visualized by polarized light microscopy at the time of intracytoplasmic sperm injection and the ploidy of the resulting embryo. Prospective cohort study. Private IVF clinic. Patients undergoing preimplantation genetic screening/diagnosis (n = 113 patients). Oocyte meiotic spindles were assessed by polarized light microscopy and classified at the time of intracytoplasmic sperm injection as normal, dysmorphic, translucent, telophase, or no visible spindle. Single blastomere biopsy was performed on day 3 of culture for analysis by array comparative genomic hybridization. Spindle morphology and embryo ploidy association was evaluated by regression methods accounting for non-independence of data. The frequency of euploidy in embryos derived from oocytes with normal spindle morphology was significantly higher than all other spindle classifications combined (odds ratio [OR] 1.93, 95% confidence interval [CI] 1.33-2.79). Oocytes with translucent (OR 0.25, 95% CI 0.13-0.46) and no visible spindle morphology (OR 0.35, 95% CI 0.19-0.63) were significantly less likely to result in euploid embryos when compared with oocytes with normal spindle morphology. There was no significant difference between normal and dysmorphic spindle morphology (OR 0.73, 95% CI 0.49-1.08), whereas no telophase spindles resulted in euploid embryos (n = 11). Assessment of spindle morphology was found to be independently associated with embryo euploidy after controlling for embryo quality (OR 1.73, 95% CI 1.16-2.60). Oocyte spindle morphology is associated with the resulting embryo's ploidy. Oocytes with normal spindle morphology are significantly more likely to produce euploid embryos compared with oocytes with meiotic spindles that are translucent or not visible.

Evaluation of meiotic spindles in thawed oocytes after vitrification using polarized light microscopy

To investigate the efficacy of the PolScope on imaging the spindle morphology in oocytes at the metaphase II stage before vitrification and after thawing. In vitro study. University infertility clinic and academic research laboratory. Oocytes at the metaphase II stage that were obtained from superovulating mice were vitrified and then thawed. Morphological features of the spindle in oocytes were evaluated by both the PolScope and immunofluorescent staining. Using the PolScope, the morphological features of the spindle of intact thawed oocytes were undetected by 3 hours of thawing in only 25% of cases. Most of the spindle images were recognized during the first hour of observation. Additionally, the statistical analysis of agreement of spindle morphology by both the PolScope and fluorescent staining showed a weighted Kappa value of 0.70, indicating good agreement. Oocytes with good spindle morphology verified by the PolScope before vitrification had a higher survival rate of intact oocytes after thawing compared with those with poor or undetected spindle images. The morphological features of the spindle in oocytes evaluated by the PolScope before freezing and after thawing are significantly correlated with those assessed by immunofluorescent staining after fixation. With the assistance of the PolScope, thawed oocytes with good spindle morphology can be verified and selected for further manipulation without fixation and staining.