Lysophosphatidic acid improves porcine oocyte maturation and embryo development in vitro

Lysophosphatidic acid (LPA), a member of the phospholipid autacoid family, is present in human follicular fluid. The aim of the present study was to compare the developmental competence of porcine embryos created via in vitro fertilization (IVF) and parthenogenetic activation (PA) in culture medium supplemented with LPA, in comparison with a control group. The effects of LPA on porcine oocyte maturation and pre-implantation embryonic development were also examined. Addition of 10 μM LPA to the oocyte maturation medium significantly increased the proportion of oocytes reaching metaphase I (MI) or metaphase II (MII), and enhanced embryonic developmental potential. When present during oocyte maturation, LPA significantly increased the abundance of phosphorylated ERK1/2 in MI and MII oocytes, showing that LPA enhanced nuclear maturation via activation of the mitogen-activated protein kinase (MAPK) pathway. In addition, Cyclin B1 levels were elevated in MI- and MII-stage oocytes, suggesting that LPA plays a role in both nuclear and cytoplasmic maturation of oocytes. After fertilization, the frequency of polyspermy in embryos obtained using LPA-treated oocytes was less than that in the control group. Further, blastocyst formation and blastocyst cell number were enhanced and apoptosis was reduced upon LPA treatment of embryos created either by IVF and PA. LPA treatment of blastocysts derived by IVF or PA resulted in increased expression of the anti-apoptotic BCL2L1 gene while reducing expression of the pro-apoptotic genes BAX and CASP3. Together, our data indicate that LPA supplementation improves porcine oocyte maturation and subsequent in vitro development of pre-implantation embryos.