DNA Methylation Alteration and B Cell Lymphoma/leukmia-2 Gene(Bcl-2) Expression of Cultured Porcine Embryos Derived from Intracytoplasmic Sperm Injection
Abstract：Using real-time PCR technique, the expression of DNA methylation associated genes(DNA methyltransferase gene: Dnmt1 and Dnmt3a) in porcine GV- and MⅡ-oocytes, 2-cell to morula embryos derived from in vitro fertilization(IVF) and intracytoplasmic sperm injection(ICSI) were analyzed, and the expression of embryonic anti-apoptotic gene(B cell lymphoma/leumia-2, Bcl-2) was examined as well. The results showed that Dnmt1 behaved high expression in the oocytes and could sharply decrease in both IVF and ICSI group during early stage of embryonic development. Compared with IVF embryos, ICSI embryos behaved similar expression pattern, which was higher only at 4-cell stage than that from IVF group. The expression of Dnmt3a started to decrease during maturation in vitro and maintained a low level at 2- to 8-cell stage and then began to increase. The expression level of Dnmt3a in ICSI embryos after 8-cell stage was lower than that of IVF embryos. With the development of embryos, the expression level of Bcl-2 mRNA in either IVF or ICSI embryos could gradually decrease, the trend of which was more evident in ICSI embryos, indicating that the ability of embryonic anti-apoptosis decreased. It may be the main cause impacting the development of embryos.
