Expression Changes in Fatty acid Metabolic Processrelated Genes in Porcine Oocytes During in Vitro Maturation

Mammalian oocytes undergo compound processes of nuclear and cytoplasmic maturation that allow them to reach MII stage. Only fully mature, oocyte can be successfully fertilized by a single spermatozoon. Fatty acids, apart from their role in cellular metabolism, inflammation and tissue development, have positive and detrimental effects on oocyte maturation, fertilization, blastocyst cleavage rate and embryo development in mammals. Using microarrays, we have analyzed the expression changes in fatty acids- -related genes during in vitro maturation of porcine oocytes. The oocytes were recovered from ovaries of 45 pubertal crossbred Landrace gilts and subsequently subjected to BCB test. For further analyses, only granulosa cell-free BCB+ oocytes were used and divided into two groups. The first one, described as “before IVM”, was directly exposed to molecular assays, the second one, described as “after IVM”, was first in vitro matured and then subjected to a second BCB test. Oocytes, if classified as BCB+, were then passed to corresponding molecular analyses. We found significant down-regulation of genes involved in fatty acid metabolic process, such as: ACSL6, EPHX2, FADS2, PTGES, TPI1, TBXAS1, NDUFAB1, MIF, ACADSB and DECR1 in porcine oocytes analyzed after IVM, in comparison to those analyzed before IVM. In conclusion, apart from poor data available concerning analyzed genes in relation to reproductive events, significant changes in their expression point to their potential role as an oocyte developmental competence markers in pigs. Introducing molecular diagnostics of oocytes could be the prospective tool for selection of best gametes, leading to improved outcomes of in vitro fertilization.