Iloprost, a Prostacyclin Analogue, Alleviates Oxidative Stress and Improves Development of Parthenogenetic Porcine Embryos via Nrf2/Keap1 Signaling.

BACKGROUND: Prostacyclin (PGI2), an abundantly produced bioactive lipid by oviductal epithelial cells, supports preimplantation embryo development by buffering oxidative stress. However, the mechanism linking PGI2 signaling to embryonic redox control remains unclear. We investigated whether Iloprost (Ilo), a stable PGI2 analogue, enhances preimplantation embryo development by alleviating oxidative stress via activation of the Nrf2/Keap1 pathway, and whether these effects depend on Nrf2 activity using the inhibitor brusatol. METHODS: Porcine embryos were treated with Ilo to model oviductal PGI2 signaling during in vitro culture. Developmental competence was evaluated by cleavage and blastocyst formation rates, and blastocyst quality by total cell number and TUNEL assays. Oxidative status was quantified by fluorescence detection of reactive oxygen species (ROS), and Nrf2 activation was assessed by nuclear localization and antioxidant-related gene expression. RESULTS: Embryos treated with Ilo showed significantly increased blastocyst formation, reduced ROS, and upregulated antioxidant genes. Immunofluorescence confirmed increased nuclear translocation of Nrf2, indicating activation of the Nrf2/Keap1 signaling pathway. In contrast, embryos treated with brusatol showed reduced blastocyst formation, increased ROS, and downregulated antioxidant-related gene expression, whereas co-treatment with Ilo reversed these effects. CONCLUSIONS: This study demonstrates that PGI2 protects embryos by activating Nrf2/Keap1 signaling, establishing this axis as a key antioxidant defense during embryonic development and highlighting its potential to improve embryo culture systems.