Current Issue

Volume 12, Number 2, Jul-Sep 2018 Pages: 157-163

Melatonin Improves The Developmental Competence of Goat Oocytes


Saghar Saeedabadi, M.Sc, 1, 2, Amir Hossein Abazari-Kia, M.Sc, 2, Hoda Rajabi, M.Sc, 2, Kazem Parivar, Ph.D, 1, Mohammad Salehi, Ph.D, 3, 4, *,
Department of Biology, Faculty of Science, Islamic Azad University, Science and Research Branch, Tehran, Iran
Department of Transgenic Animal Science, Stem Cell Technology Research Center, Tehran, Iran
Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
*Corresponding Address: P.O.Box: 193954717 Cellular and Molecular Biology Research Center Shahid Beheshti University of Medical Sciences Tehran Iran Email:m.salehi@sbmu.ac.ir

Abstract

Background

DNA methylation is one the epigenetic mechanisms, which is critically involved in gene expression. This phenomenon is mediated by DNA methyl-transferases and is affected by environmental stress, including in vitro maturation (IVM) of oocytes. Melatonin, as an antioxidant, may theoretically be involved in epigenetic regulation via reductions of reactive oxygen species. This study was performed to investigate DNA methylation and the possibility of goat oocyte development after treatment with different concentrations of melatonin.

Materials and Methods

This experimental study was performed to investigate DNA methylation and the possibility of goat oocyte development after treatment with different concentrations of melatonin. For this purpose, oocytes with granulated cytoplasm were selected and co-cultured with at least two layers of cumulus cells in maturation medium with 10-6M, 10-9M, 10-12M and 0-M (as control group) of melatonin. Nucleus status, glutathione content and devel- opmental competence of the oocytes in each experimental group were assessed. Also, expression of genes associated with DNA methylation, including DNA methyltransferase 1 (DNMT1), DNA methyltransferase 3b (DNMT3b) and DNA methyltransferase 3a (DNMT3a) was evaluated by quantitative real time-polymerase chain reaction (RT-PCR).

Results

According to our findings, the percentage of oocytes that reached the M-II stage significantly increased in the 10-12 M group (P<0.05). Also, a significant elevation of glutathione content was observed in melatonin-treated oocytes (P<0.05). Analysis of blastocyst formation revealed that developmental competence of the oocytes was higher than the control group (P<0.05). It was observed that melatonin treatment decreased expression levels of DNA meth- yltransferases (DNMTs) and global DNA methylation (P<0.05). In addition, the expression of melatonin receptor1A (MTNR1A) was detected in both cumulus and oocyte by RT-PCR.

Conclusion

The results suggested that in goat model melatonin affects DNA methylation pattern, leading to an im- provement in the developmental competence of the oocytes.