The Effects of Oocyte Exposure to Bisphenol A On Early Bovine Embryo Development
Bisphenol A (BPA) is an endocrine disrupting chemical that can have detrimental effects on oocytes and subsequent embryo development. BPA is one of the highest volume chemicals produced worldwide and can be found in a wide range of everyday products including plastic containers and cans. In this study, bovine oocytes were matured in vitro under various treatment conditions namely no-treatment control, vehicle (1% ethanol), 0.005 mg/mL, 0.05 mg/mL, and 0.5 mg/mL BPA. Cleavage and blastocyst rates decreased in the BPA treated groups. The expression levels of specific survival, stress and epigenetic markers were assessed. HSP70 mRNA and protein expression levels remained unchanged in the oocyte and blastocyst. There was a significant decrease in DNMT1 protein expression at the oocyte level, however a significant increase was seen in the mRNA expression in the blastocysts. BPA exposure during oocyte maturation in vitro can therefore decrease developmental parameters and affect DNA methylation.