Does combination of estradiol and sesame oil improve the oocyte quality, embryo development and expressions of Zp3, E-cad, and Ctnnb1 genes in mice? An experimental study

BACKGROUND: Aging may reduce oocyte maturation, embryo quality, and fertility potential. OBJECTIVE: To compare the effect of estradiol (E2) and sesame oil on oocyte and embryo quality between young and old mice. MATERIALS AND METHODS: Sixty old and young female mice were divided in to two groups (30 mice/group, grouped by age). Each group was divided into three subgroups of mice treated with sesame oil, E2 + sesame oil, and normal saline as control group. After ovulation induction, some oocytes were considered for in vitro fertilization and the rest were assessed for morphological status. After obtaining the two-cell embryos, the embryos were collected to determine the expression of zona pellucida (ZP) glycoprotein 3, E-cadherin, and β-catenin genes and some of them followed until the blastocysts stage to evaluate the viability. RESULTS: The findings showed that the mean ZP and perivitelline space thickness increased in the old mice that received the E2 + sesame oil treatment. The number of 2-cell embryos, blastocysts, and live cells were significantly higher in the old group treated with sesame oil respectively (p = 0.018, 0.002, and [Formula: see text] 0.0001, respectively). The normal ZP shape and refractile body numbers increased in the old mice that were treated with sesame oil, respectively. The E-cadherin gene was downregulated in the treatment groups compared to the controls. CONCLUSION: Sesame oil showed a better response in the old mice, because aging is associated with an increased rate of reactive oxygen species, causing deficiencies in both oocyte and embryo qualities.