Metformin, clomiphene citrate and flutamide effects on oocyte ultrastructure status and quality in PCOS mouse model

Polycystic ovary syndrome (PCOS) alters oocyte developmental competence and so the treatment of PCOS patients with assisted reproductive techniques is a major challenge for an infertility specialist. Does ovulation induction therapy with clomiphene citrate, metformin and flutamide affect abnormal PCOS follicle gene expression, its quality, and nuclear and cytoplasmic maturation in the oocyte matured in vitro?

Fifty NMRI mice (7-8 weeks old) were randomly divided into five groups, including non-PCOS, PCOS and PCOS groups treated with clomiphene citrate (18 mg/kg body weight for 2 days), metformin (50 mg/100 g body weight for 30 days) and flutamide (10 mg/kg body weight injection for 15 days). The oocytes were collected for quantitative real-time polymerase chain reaction analysis (the evaluation of genes associated with oocyte maturation), transmission electron microscopy (the evaluation of cytoplasmic maturation) and in-vitro maturation (IVM) and IVF outcomes.

The dysregulated expression of some genes of insulin-like growth factor (IGF) families involved in oocyte competence and steroid metabolism (e.g. Cyp19a1 and Cyp11a1), transforming growth factor beta (TGF-β) family (e.g. Tgfb1, Gdf9, Bmp15, Inhbb and Bmpr1a), and oestrogen receptor signalling (e.g. Ncoa3, Pgr) was, to some extent, restored in the PCOS follicles following their with clomiphene citrate, metformin and flutamide. The improved cytoplasmic maturation was observed particularly in the PCOS mice treated with clomiphene citrate. The better IVM-IVF outcomes were also observed in the clomiphene citrate and metformin groups compared with the PCOS group.

This study opens up a new perspective on knowing the effect of ovulation induction therapy on not only nuclear maturation but also ultrastructural characteristics, IVM-IVF outcomes and PCOS oocyte developmental competence.