Maslinic Acid Supplementation during the In Vitro Culture Period Ameliorates Early Embryonic Development of Porcine Embryos by Regulating Oxidative Stress

SIMPLE SUMMARY: High-quality early embryos are essential for accelerating animal reproduction and genetic modification of mammals, and oxidative stress is strongly associated with a decline in in vitro embryo developmental potential. During in vitro culture, the most direct and effective approach to alleviate oxidative stress is to add antioxidants to the in vitro culture medium. In this study, maslinic acid (MA), a pentacyclic triterpenoid acid in olive plants possessing antioxidant capacities due to its ability to scavenge free radicals, ameliorated the in vitro developmental capability of porcine embryos from parthenogenetic activation and somatic cell nuclear transfer. MA also enhanced oxidation resistance, maintained mitochondrial function, and inhibited apoptosis in porcine early-stage embryos. ABSTRACT: As a pentacyclic triterpene, MA exhibits effective free radical scavenging capabilities. The purpose of this study was to explore the effects of MA on porcine early-stage embryonic development, oxidation resistance and mitochondrial function. Our results showed that 1 μM was the optimal concentration of MA, which resulted in dramatically increased blastocyst formation rates and improvement of blastocyst quality of in vitro-derived embryos from parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT). Further analysis indicated that MA supplementation not only significantly decreased the abundance of intracellular reactive oxygen species (ROS) and dramatically increased the abundance of intracellular reductive glutathione (GSH) in porcine early-stage embryos, but also clearly attenuated mitochondrial dysfunction and inhibited apoptosis. Moreover, Western blotting showed that MA supplementation upregulated OCT4 (p < 0.01), SOD1 (p < 0.0001) and CAT (p < 0.05) protein expression in porcine early-stage embryos. Collectively, our data reveal that MA supplementation exerts helpful effects on porcine early embryo development competence via regulation of oxidative stress (OS) and amelioration of mitochondrial function and that MA may be useful for increasing the in vitro production (IVP) efficiency of porcine early-stage embryos.