Correlation between steroid levels in follicular fluid and hormone synthesis related substances in its exosomes and embryo quality in patients with polycystic ovary syndrome

Background: Polycystic ovary syndrome (PCOS) is an endocrine and metabolic disorder with various manifestations and complex etiology. Follicular fluid (FF) serves as the complex microenvironment for follicular development. However, the correlation between the concentration of steroid in FF and the pathogenesis of PCOS is still unclear. Methods: 20 steroid levels in FF from ten patients with PCOS and ten women with male-factor infertility undergoing in vitro fertilization were tested by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in order to explore their possibly correlation with PCOS. Meanwhile, the mRNA levels of core enzymes in steroid synthesis pathway from exosomes of FF were also detected by qPCR. Results: The estriol (p < 0.01), estradiol (p < 0.05) and prenenolone (p < 0.01) levels in FF of PCOS group were significantly increased, compared to the normal group, and the progesterone levels (p < 0.05) were decreased in PCOS group. Increased mRNA levels of CYP11A, CYP19A and HSD17B2 of exosomes were accompanied by the hormonal changes in FF. Correlation analysis showed that mRNA levels of CYP11A and HSD17B2 were negatively correlated with percent of good-quality embryos and rate of embryos develop to blastocyst. Conclusions: Our results suggest that increased levels of estrogen and pregnenolone in follicular fluid may affect follicle development in PCOS patients, and the mechanism is partially related to HSD17B1 , CYP19A1 and CYP11A1 expression change in FF exosomes.