Potential effects of age-associated oxidative stress on mammalian oocytes/embryos

Abstract

This bioessay aims to explain the different effects of maternal ageing and postovulatory oocyte ageing on mammalian oocytes/embryos under the scope of 'the oxygen radical-mitochondrial injury hypothesis of ageing'. This hypothesis assumes a key role in the senescent process of oxygen radical damage to mitochondrial DNA, proteins and lipids. It is proposed that a decrease in intracellular ATP concentrations and glutathione (GSH)/glutathione disulphide (GSSG) ratio together with a concomitant increase in cytosolic Ca2+ are major factors causing the observed detrimental effects of ageing on cytoskeletal fibres, fertilization and embryo development.

The protective effects of human umbilical cord mesenchymal stem cells on damaged ovarian function: A comparative study

“…The products produced by oxidative stress during daily metabolism may cause aging (11). Long-term greater oxidative stress damage may be involved in the process of ovarian aging (12,13). Previous studies have indicated that oxidative stress harms oocyte development.…”

Differences in cumulus cells gene expression between modified natural and stimulated in vitro fertilization cycles

“…It seems that ovarian ROS production is triggered by LH and is essential for ovulation, as the use of antioxidants significantly reduces ovulation rate, prevents LH-induced cumulus expansion, lowers progesterone secretion and down-regulates genes essential for ovulation [33]. However, pathological levels of ROS in follicular fluid diminish oocyte and embryo quality [34][35][36] and hava a negative impact on IVF outcome [37]. Increased percentage of ROS producing granulosa cells (GC) has a negative impact on the number of oocytes retrieved and diminishes implantation rate in IVF procedures [38].…”

Effect of apoptosis and reactive oxygen species production in human granulosa cells on oocyte fertilization and blastocyst development

“…There is evidence that ROS can damage oocytes and reduce their fertilization competence [13]. Oxidative stress in granulosa cells was found to lower fertilization rates and decrease quality of embryos in IVF cycles [14].…”

“…Low ROS concentrations in the follicular fluid have been proposed to be important for successful IVF outcome [12]. It seems that increased ROS levels impair oocyte and embryo quality [13,14].…”