Background: This study evaluated association between glucose uptake by individually cultured oocyte and their maturation competence in mice with polycystic ovarian syndrome (PCOS).
Materials and methods: In this experimental study, PCOS and non-PCOS cumulus-oocyte complexes (COCs), and cumulus-denuded oocytes (DOs) were cultured individually and categorized in four groups: i. PCOS DOs (n=83), ii. PCOS COCs (n=35), iii. Non-PCOS DOs (n=61) and iv. Non-PCOS COCs (n=62). After the culture period, 50 μl aliquots of the spent drops were used for glucose change analysis using high performance liquid chromatography. Polar NH2 column was used for the study of carbohydrates, acetonitrile with deionized water as the solvent phase and UV as detectors. Oocyte quality (growth differentiation factor 9: GDF-9), viability [bcl-2-like protein 4 (BAX) and B-cell lymphoma2 (BCL2)], in addition to fertilization and embryonic development rates were also evaluated in relation to glucose consumption rate of each oocyte.
Results: Maturation rate was significantly higher in non-PCOS COCs and DOs compared to PCOS COCs (IV: 70.9% vs. II: 45.71%) and DOs (III: 67.2% vs. 1: 53.01%), respectively. There was a significant negative correlation between high glucose intake (38.17 ppm) and BCL2 gene expression (P=0.03) in PCOS COCs compared to non-PCOS COCs. There was a significant difference in the GDF-9 gene expression from PCOS DOs (0.66 ± 0.02, P=0.003) and COCs (0.37 ± 0.02, P=0.0001) compared to non-PCOS DOs and COCs, respectively. A negative correlation was also observed between quality of PCOS-DOs and -COCs with glucose intake. Non-PCOS COCs significantly showed higher rate of successful IVF and development compared to PCOS COCs (P=0.01).
Conclusion: Based on the importance of metabolic analysis, the glucose consumption by DOs and COCs in culture medium can be a suitable criterion for their quality assessment. So that, glucose consumption may reflect oocyte maturation competence.
Keywords: Glucose intake; HPLC; IVM; Oocyte Quality; PCOS.