Melatonin protects against visible light-induced oxidative stress and promotes the implantation potential of mouse blastocyst in vitro

Improvement of embryo culture media using antioxidant agents could help to improve embryo quality against environmental factors such as visible light and could overcome implantation failures. The usefulness of the melatonin against the effect of light on the expression of the primary implantation receptors, ErbB1 and ErbB4 on pre-implantation mouse embryo was investigated. Two-cell mouse embryos were exposed to the 1600 LUX light for 30 min then randomly divided into 3 groups including: Melatonin-Treated; Luzindole Treated and Simple media as a Control group. After 72-96 The expanded blastocysts were examined for morphological quality of the embryos by Hoechst and propidium iodide staining and for the expression of ErbB1 and ErbB4 by Real-time PCR and immunocytochemistry. The expression of the Sirt3 gene was also assayed. Furthermore, intracellular reactive oxygen species (ROS) levels and the total antioxidant capacity (TAC) were examined by DCFH-DA fluorescence intensity and radical cation respectively.The number of cells in the inner cell mass (ICM) and outer cell mass (OCM) were elevated significantly in the Melatonin-treated group suggesting increased viability and proliferation. Furthermore, we found that melatonin significantly increased the expression levels of ErbB1, ErbB4, and Sirt3 genes, and the protein expression of ErbB1, ErbB4 correlated with intracellular ROS levels and TAC significantly increased after melatonin treatment. Together, these results demonstrate that melatonin could be helpful to improve preimplantation embryos through its effects in decreasing ROS levels and increasing expression of implantation-related genes.