Reactive oxygen species generation and use of antioxidants during in vitro maturation of oocytes: a Review

In vitro maturation (IVM) is emerging as a popular technology at the forefront of fertility treatment and preservation. However, standard in vitro culture conditions usually increase reactive oxygen species (ROS), which have been implicated as one of the major causes for reduced embryonic developmental competence. It is well-known that higher than physiological levels of ROS triggers granulosa cell apoptosis and thereby reduces the transfer of nutrients and survival factors to the oocytes, leading to apoptosis. ROS are neutralized by an elaborate defense system consisting of enzymatic and non-enzymatic antioxidants. Furthermore, balance between level of ROS and antioxidants within IVM media are important for maintenance of oocytes developing to the blastocyst stage. Quite naturally, effects of antioxidant supplementation of IVM media have been studied in various mammalian species. Therefore, this article reviews briefly and summarizes the effects of ROS on oocyte quality and the use of antioxidant supplementations for IVM, its effects on maturation rates and further embryo development.