Redox homeostasis in human follicular fluid: A comparison of modified natural cycle and controlled ovarian stimulation in idiopathic infertility.

Cellular metabolism within follicle continuously generates reactive oxygen species (ROS). This study aimed to investigate the biochemical composition related to redox homeostasis, inflammatory markers, and microelements in follicular fluid (FF) of women with idiopathic infertility. Additionally, it sought to compare these parameters among: (i) modified natural cycles (mNC) and controlled ovarian stimulation (COS), (ii) fertilization success, and (iii) IVF outcome. Follicular fluid samples were collected from women undergoing mNC as well as COS using gonadotropin-releasing hormone (GnRH) antagonists. Follicular fluid analysis included measuring the concentrations of: malondialdehyde, 15-F2t-isoprostane, vitamin E, and the total activity of superoxide dismutase (SOD). Microelements, copper and zinc, were measured, along with the inflammation marker interleukin 6. A total of 60 women under the age of 42, participated in the study. Malondialdehyde, β-carotene, copper, zinc and interleukin-6 in FF differed significantly between the group with COS and the group from mNC. Successful fertilization is linked by higher concentrations of vitamin A, copper and zinc and interleukin-6. The pregnant group have increased copper concentrations in FF. Ovarian stimulation using a GnRH antagonist protocol may induce oxidative stress and inflammatory changes in FF, associated with increased antioxidant demand and microelements concentrations. Successful fertilization is linked with antioxidant response marked by higher concentrations of vitamin A, and copper and zinc. Increased IL-6 concentrations may indicate a favorable inflammatory and oxidative environment supporting fertilization. Increased copper concentrations in the pregnant group can be potential factor but it requires further investigation.