Iloprost affects in vitro maturation and developmental competence of bovine oocytes

Abstract

Prostacyclin (PGI2) is synthesised in oviductal fluid and enhance the embryo development during the preimplantation period. The objective of the present study was to determine the effect of an analogue of prostacyclin (iloprost) on the in vitro maturation (IVM) and the developmental competence of bovine oocytes. Cumulus oocyte complexes (COCs) were cultured in maturation medium with iloprost (0.5 μM) for 24 h. We found that iloprost assisted maturation rates and cumulus cell expansion of bovine oocytes, and it increased the mRNA expression of genes related to cumulus expansion: ADAM17, AREG, and TNFAIP6 and cathepsin genes (CTSK and CTSS). Moreover, iloprost reduced the occurrence of apoptosis in COCs and promoted an antiapoptotic balance in the transcription of genes involved in apoptosis (BAX and BCL2). COCs treatment with iloprost during IVM also reduced intracellular reactive oxygen species (ROS) levels, while glutathione (GSH) levels and the mRNA expression of antioxidant genes CAT and GPx4 were markedly increased. We also showed that an analogue of PGI2 influenced the mitochondrial status via distribution rates of mitochondria and mitochondrial membrane potential in oocytes. Although, iloprost-enhanced maturation had no direct effect on number of embryos cleaved, it increased blastocyst rates of bovine embryos as well as proportion of expanded blastocysts. These results indicate that the supplementation of maturation medium with iloprost is beneficial for the maturation efficiency and developmental competence of bovine oocytes.