The Role of Follicular Fluid Thiol/Disulphide Homeostasis in Polycystic Ovary Syndrome

BACKGROUND: Oxidative stress has been proposed as a potential trigger in the etiopathogenesis of polycystic ovary syndrome-related infertility. Thiol/disulphide homeostasis, a recently identified oxidative stress marker, is one of the antioxidant mechanism in humans with critical roles in folliculogenesis and ovulation.

AIMS: To investigate follicular fluid thiol/disulphide homeostasis in the etiopathogenesis of polycystic ovary syndrome and to determine its association with in vitro fertilization outcome. The study procedures were approved by the local ethics committee.

STUDY DESIGN: Cross-sectional study.

Methods: Follicular fluid from 22 women with polycystic ovary syndrome and 20 ovulatory controls undergoing in vitro fertilization treatment was sampled. Thiol/disulphide homeostasis was analyzed via a novel spectrophotometric method.

Results: Follicular native thiol levels, as well as the native thiol/total thiol ratio, were lower in the polycystic ovary syndrome group than in the non-polycystic ovary syndrome group (p=0.041 and p<0.0001, respectively). Disulphide levels, disulphide/native thiol, and disulphide/total thiol ratios were increased in the polycystic ovary syndrome group (p<0.0001). A positive correlation between the fertilization rate and native thiol (p=0.01, r=0.53) and total thiol (p=0.01, r=0.052) among polycystic ovary syndrome patients was found. A positive predictive effect of native thiol level on the fertilization rate in the polycystic ovary syndrome group was also found (p=0.03, β=0.45, 95% CI= 0.031-0.643).

Conclusion: Deterioration of thiol/disulphide homeostasis, especially elevated disulphide levels, could be one of the etiopathogenetic mechanisms in polycystic ovary syndrome. Increased native thiol levels are related to the fertilization rate among polycystic ovary syndrome patients and are positive predictors of the fertilization rate among polycystic ovary syndrome patients. Improvement of thiol/disulphide homeostasis could be important in the treatment of polycystic ovary syndrome to increase in vitro fertilization success.