The Effect of Sodium Selenite on Expression of Mitochondrial Transcription Factor A during In Vitro Maturation of Mouse Oocyte

Abstract

Background: The aim of the present study was to investigate the effect of Sodium Selenite (SS) supplemented media on oocyte maturation, expression of mitochondrial transcription factor A (TFAM) and embryo quality.

Methods: Mouse Germinal Vesicle (GV) oocytes were collected after administration of Pregnant Mare Serum Gonadotropin (PMSG); in experimental group 1, oocytes were cultured and then subjected for in vitro maturation in the absence of SS, and in experimental group 2, they were matured in vitro in the presence of 10 ng/ml of SS up to 16 hr. The control group included MII oocytes obtained from the fallopian tubes after ovarian stimulation with PMSG, followed by human chorionic gonadotropin. Then, the expression of TFAM in MII oocytes in all three groups was investigated using real-time RT-PCR. The fertilization and embryo developmental rates were assessed, and finally the quality of the blastocysts was evaluated using propidium iodide staining.

Results: The oocyte maturation rate to MII stage in SS treated group was significantly higher than non-treated oocytes (75.65 vs. 68.17%, p<0.05). Also, the rates of fertilization, embryo development to blastocyst stage as well as the cell number of blastocyst in SS supplemented group were higher than other experimental group (p<0.05). There was a significant decrease in TFAM gene expression in both in vitro groups compared to the group with in vivo obtained oocytes (p<0.05). Moreover, there was a significant increase in TFAM gene expression in oocytes that matured in the presence of SS compared to that of the group without SS (p<0.05).

Conclusion: Supplementation of oocyte maturation culture media with SS improved the development rate of oocytes and embryo and also enhanced TFAM expression in MII oocytes which can affect the mitochondrial biogenesis of oocytes.