Effects of In Vitro Maturation on Histone Acetylation in Metaphase II Oocytes and Early Cleavage Embryos

Ning Wang,Min-Yue Dong,He-Feng Huang,Chen-Ming Xu,Qi-Tao Zhan,Li Li,Guo-Lian Ding,Fang Le,Fan Jin,Shi-Wen Jiang

doi:10.1155/2010/989278

Abstract

In vitro maturation (IVM) of oocyte is an effective procedure for avoiding ovarian hyperstimulation syndrome in patients with polycystic ovaries (PCOS) during in vitro fertilization (IVF). To investigate the influences of IVM on epigenetic reprogramming and to search for the possible reasons for the lower rates of fertilization and cleavage in IVM oocytes, we examined the expression of two enzymes controlling histone acetylation, histone acetyltransferase GCN5 (GCN5) and histone deacetylase 1 (HDAC1), as well as their common target, acetyl-histone H3 (Ac-H3), in mouse metaphase II (MII) oocytes and preimplantation embryos. Results showed that IVM downregulated the protein expression of GCN5 in MII oocytes and two-cell embryos and changed the distribution of GCN5 in two-cell embryos. Expression of HDAC1 mRNA in MII oocytes and two-cell embryos decreased in the IVM group. However, none of these changes persisted after two-cell embryos. Levels of Ac-H3 in both oocytes and embryos remained unchanged after IVM. Our studies indicated that IVM could affect the protein and gene expression related to histone acetylation in oocytes and early cleavage embryos. By function of selection, parts of the changes could be recovered in late embryo development.

Highlights

In vitro fertilization and embryo transfer (IVF-ET) are an effective treatment for infertility [1, 2]
To investigate the influences of In vitro maturation (IVM) on epigenetic reprogramming and to search for the possible reasons for the lower rates of fertilization and cleavage in IVM oocytes, we examined the expression of two enzymes controlling histone acetylation, histone acetyltransferase GCN5 (GCN5) and histone deacetylase 1 (HDAC1), as well as their common target, acetyl-histone H3 (Ac-H3), in mouse metaphase II (MII) oocytes and preimplantation embryos
We found that histone acetylation in oocytes, early cleavage embryos, and was changed in IVM group

Summary

Introduction

In vitro fertilization and embryo transfer (IVF-ET) are an effective treatment for infertility [1, 2]. The high costs of gonadotropin administration, the risk of ovarian hyperstimulation syndrome (OHSS), and the possible association between repeated ovarian stimulation and hormonerelated cancers are the main drawbacks of IVF-ET. In-vitro maturation (IVM) offers an alternative to conventional IVF that minimizes medicine administration and avoids ovarian hyperstimulation. Poor responders to gonadotropin stimulation may benefit from IVM as they do not need to receive a large dosage of gonadotropins. With the cryopreservation of reproductive cells, IVM can offer to preserve fertility in women who are undergoing cancer treatment [3]. More than 1000 children have been born from IVM procedures, in the patients with PCOS [4, 5]. IVM remains a challenge in mammalian species, especially for human

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Conclusion