Oxidative stress in oocyte and embryo development: implications for in vitro systems

SIGNIFICANCE To improve the outcome of in vitro culture of human oocytes and embryos, the dynamic balance and roles of reactive oxygen species (ROS) in folliculogenesis and embryo development merit further consideration. Recent Advances: ROS have been demonstrated to participate in various signaling processes and act as mediators in various physiological events in germ cells. An imbalance between prooxidants and antioxidants seems to explain the high failure rate of assisted reproduction. CRITICAL ISSUES Oxidative stress induced by excessive ROS or insufficient antioxidant protection can cause detrimental effects on both male and female reproduction. In this study, the oxidative stress in folliculogenesis and embryo development are summarized and the multiple modifiable factors of the in vitro culture systems in relation to the ROS are discussed. FUTURE DIRECTIONS More studies are needed to establish an optimal redox state in the in vitro culture systems for human oocytes and embryos.