Effect of Antioxidant Treatment during Parthenogenetic Activation Procedure on the Reactive Oxygen Species Levels and Development of the Porcine Parthenogenetic Embryos

The present study was conducted to examine the effect of antioxidant treatment during parthenogenetic activation procedure on the reactive oxygen species (ROS) levels and in vitro development of porcine parthenogenetic embryos. Porcine in vitro matured oocytes were activated by a combination of electric stimulus and 2 mM 6-dimethylaminopurine (6-DAMP) before in vitro culture. During the activation period, oocytes were treated with $50{\mu}M$ ${\beta}$-mercaptoethanol (${\beta}$-ME), $100{\mu}M$ L-ascorbic acid (Vit. C) or $100{\mu}M$ L-glutathione (GSH). To examine the ROS level, porcine parthenogenetic embryos were stained in $10{\mu}M$ dichlorohydrofluorescein diacetate ($H_2DCFDA$) dye 20 h after culture, examined under a fluorescence microscope, and the fluorescence intensity (pixels) were analyzed in each embryo. The parthenogenetic embryos were cultured for 6 days to evaluate the in vitro development. The apoptosis was measured by TUNEL assay. The $H_2O_2$ levels of parthenogenetic embryos were significantly lower in antioxidant treatment groups ($26.9{\pm}1.6{\sim}29.1{\pm}1.3$ pixels/embryo, p<0.05) compared to control ($33.2{\pm}1.7$ pixels/embryo). The development rate to the blastocyst stage was increased in antioxidant treatment groups (32.0~32.5%) compared to control (26.9%, p<0.05), although, there was no difference in apoptosis among groups. The result suggests that antioxidant treatment during parthenogenetic activation procedure can inhibit the ROS generation and enhance the in vitro development of porcine parthenogenetic embryos.