Past Issue

Volume 20, Number 3, Autumn 2018, Serial Number: 79, Pages: 396-402

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


Nassim Ghorbanmehr, Ph.D, 1, 2, Mojdeh Salehnia, Ph.D, 1, *, Mahboobeh Amooshahi, Ph.D, 1,
Department of Anatomy, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
Department of Biotechnology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran
*Corresponding Address: P.O. Box: 14115-111 Department of Anatomy Faculty of Medical Sciences Tarbiat Modares University Tehran Iran Email:salehnim@modares.ac.ir

Abstract

Objective

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.

Materials and Methods

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).

Results

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<0.05). The intensity of mitochondrial staining was not different among the studied groups, whereas the mitochondria distribution in the cytoplasm of the IVM oocytes showed some aggregation pattern. The in vivo obtained MII oocytes had lower ROS levels and higher mtDNA copy numbers than IVM-MII oocytes (P<0.05). The SS supplemented group had significantly lower ROS levels and higher mtDNA copy numbers than the non-treated group (P<0.05).

Conclusion

SS increased oocyte mtDNA copy number by decreasing oxidative stress. SS had an association with better oocyte developmental competence.