Effect of 7,8-Dihydroxyflavone on In Vitro Maturation of Oocytes and Development of Parthenotes in Pigs

Abstract

One of the factors that impair the in vitro produced porcine embryos is the oxidative stress that mainly caused by the imbalance between reactive oxygen species (ROS) generation and antioxidants activity, especially glutathione (GSH). Here, the effect of 7,8-dihydroxyflavone (7,8-DHF), a flavonoid antioxidant, on porcine oocyte maturation and its developmental competence was examined. Porcine oocytes were cultured in media supplemented with 0, 1, 5, and 10 μM 7,8-DHF during both in vitro maturation (IVM) and in vitro culture (IVC) after parthenogenetic activation. Maturation of oocytes was evaluated based on the 1st polar body (PB) extrusion and intracellular GSH level and developmental competence was assessed through observing cleavage and blastocyst formation. In each step, the levels of intracellular GSH and ROS were assessed by fluorescence intensity and the apoptosis-related gene expression was examined using semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Parthenogenetic mbryos treatment with 1 μM 7,8-DHF during IVM and IVC showed increased cytoplasmic maturation and reached blastocysts stage (36.1 ± 3.5%) at a higher rate than the other groups (24.7 ± 3.1, 16.0 ± 2.6, and 10.3 ± 2.2%, P < 0.05). In that group, intracellular GHS level was significantly increased after IVM and IVC and ROS was decreased after IVC (P < 0.05). Moreover, it showed high expression of anti-apoptotic gene (BCL2L1) and low expression of pro-apoptotic gene (BAK1) (P < 0.05). In conclusion, 1 μM 7,8-DHF treatment during IVM and IVC showed an anti-apoptotic effect by increasing intracellular GSH synthesis and scavenging ROS, therefore, it improves the developmental competence of porcine parthenogenetic embryos.