Oxidative stress and oocyte microenvironment

Abstract

Abstract Preservation of the ovarian pool is a very important factor that is subject to insult by a number of extrinsic and intrinsic factors. Moderate escalation of ROS acts favorably for oocyte maturity. Nevertheless, higher levels worsen the oocyte quality, thus impacting the reproductive capability. Increases of age and psychological stress are the two most important factors that influence the magnitude, together with the fertilizing capacity of the oocytes. Abnormal levels of stress markers such as adrenaline and cortisol have been recorded on the oocyte pickup day exhibiting high levels of anxiety in infertile females, unveiling the influence of stress on the hypothalamic–pituitary–adrenal (HPA) axis. SIRT1 is an efficient antioxidant found in the oocyte where it regulates energy production by the mitochondria. Mitochondrial enzymes, including MnSOD, acting as antioxidants within the oocytes are deacylated by SIRT1. Conservation of the oxidative setting seems to be required for the maturation of the follicles and endothelium; however, oxidants hamper the follicular maturity. Levels of oxidants and antioxidants are fairly different between individuals with an endometrial thickness cut-off of 0.8\u2009mm and among those with a follicular size of 2\u2009cm more or less.