Effects of oviductal fluid on the development, quality, and gene expression of porcine blastocysts produced in vitro

Abstract

In mammals, fertilization and early pre-implantation development occur in the oviduct. Previous results obtained in our laboratory have identified specific molecules in the oviduct that affect porcine sperm-egg interactions. The aim of the present study was to determine whether the contact between oocytes and oviductal fluid also affect embryo development, quality, and gene expression. In vitro matured porcine oocytes were exposed to bovine oviductal fluid (bOF) for 30 min prior to fertilization. Cleavage and blastocyst development rates were significantly higher from bOF-treated oocytes than from untreated oocytes. Blastocysts obtained from bOF-treated oocytes had significantly greater total cell numbers than those obtained from untreated oocytes. Using real-time PCR, grade 1 (very good morphological quality) and grade 2 (good morphological quality) blastocysts were analyzed for gene transcripts related to apoptosis (BAX, BCL2L1), mitochondrial DNA (mtDNA) transcription/replication (POLG, POLG2, and TFAM), blastomere connection and morula compaction (GJA1), and blastocyst formation and pluripotency (POU5F1). We found that the entire set of genes analyzed was differentially expressed between grade 1 and 2 blastocysts. Furthermore, bOF treatment reduced the ratio of BAX to BCL2L1 transcripts and enhanced the abundance of TFAM transcripts in grade 2 blastocysts. Not only do these findings demonstrate that factors within the bOF act on porcine oocytes both quickly and positively, but they also suggest that such factors could promote embryo development and quality by protecting them against adverse impacts on mtDNA transcription/replication and apoptosis induced by the culture environment.

Deleted in malignant brain tumor 1 is secreted in the oviduct and involved in the mechanism of fertilization in equine and porcine species

“…Our results confirm the beneficial effect of oviductal fluid showed in previous studies , Lloyd et al 2009). These studies reported that exposure of oocytes to periovulatory oviductal fluid increased ZP resistance to proteolytic digestion and monospermic rates after IVF in porcine and bovine species.…”

Activin/Nodal Signaling Switches the Terminal Fate of Human Embryonic Stem Cell-derived Trophoblasts

“…Follistatin treatment increases TE formation in bovine blastocysts, whereas follistatin knockdown or activin A treatment decreases TE formation (92,93). Inhibitors of activin/nodal signaling are expressed in human fallopian tubes (94) and rat oviductal fluid (95,96), and human oviductal cells cause blastocyst formation in mouse embryos (97)(98)(99)(100)(101). Therefore, it is likely that inhibition of activin/nodal signaling has a role in TE formation in embryos.…”

Oxidative Stress in Unexplained Female Infertility

“…Oviduct provides an optimal environment for gamete maturation, fertilization and early embryonic development. It is an active organ that maintains and modulates the fluidic milieu for sperm capacitation, fertilization, and early embryonic development [85][86][87]. The environmental and metabolic stimuli from the oviduct may have a significant effect on embryonic development.…”