The Effects of Sodium Selenite on Mitochondrial DNA Copy Number and Reactive Oxygen Species Levels of In Vitro Matured Mouse Oocytes

The aim of present study is to determine the effects of supplementation of oocyte maturation medium with sodium selenite (SS) on oocyte mitochondrial DNA (mtDNA) copy number and reactive oxygen species (ROS) levels.
In this experimental study germinal vesicle (GV), metaphase I (MI), and metaphase II (MII) stage oocytes were recovered from 6-8 week old female mice after superovulation. Some of the GV oocytes were cultured and matured in the presence and absence of SS. Then in vivo and in vitro matured (IVM) oocytes were subjected to mitochondria staining by MitoTracker green, ROS analysis, and mtDNA copy number determination using absolute real-time polymerase chain reaction (PCR).
The maturation rate of GV oocytes to the MII stage significantly increased in the SS supplemented group (79.25%) compared to the control group (72.46%, P SS increased oocyte mtDNA copy number by decreasing oxidative stress. SS had an association with better oocyte developmental competence.