Protein modification as oxidative stress marker in follicular fluid from women with polycystic ovary syndrome: the effect of inositol and metformin

The purpose of this study was to evaluate the oxidative stress status (OS) of follicular fluid (FF) and the oocyte quality in women with polycystic ovary syndrome (PCOS) undergoing different ovarian stimulation protocols. FF samples were collected after gonadotropin administration in association or not with metformin or D-chiro-inositol (DCI). OS status was then evaluated by checking the follicular fluid protein oxidation profile after specific labeling of aminoacidic free-SH groups, and two-dimensional electrophoresis followed by qualitative and semiquantitative analysis. Oocyte quality was assessed by international morphological criteria. Our data indicated that both treatments, even if to different extent, recovered a significantly high level of free-SH groups in FF proteins of PCOS women clearly indicating a decrease of OS level with respect to that found in FF samples from gonadotropins alone treated women. A higher number of good quality MII oocytes was also observed in DCI (P < 0.05) or metformin (P < 0.05) study groups in comparison to untreated control group. A natural supplement and a drug both showed a statistically significant positive effect on follicular milieu by decreasing the oxidative damage on FF proteins, as well as in recovering good quality oocytes.