<scp>TW</scp> ‐7 Alleviate Apoptosis of Embryos Derived From Vitrified <scp>MII</scp> Oocytes by Downregulation of <scp>JNK</scp> Signaling in Mice

Previous studies have shown that walnut-derived peptide TW-7 is a powerful antioxidant, which can significantly improve the embryonic development potential of vitrified mouse MII oocytes. However, the underlying mechanism is still unknown. RNA sequencing indicated that the differentially expressed genes of the parthenogenetic two-cell embryos in the fresh, vitrification, and TW-7 treatment groups were significantly enriched in cell death pathways like apoptosis and necroptosis. Further analysis of the genes enriched in the cell death pathway found that mapk10, a key regulatory gene of apoptosis, showed high expression in the vitrification group but obviously low expression in the fresh and TW-7 treatment groups. Immunofluorescence staining and western blot revealed that TW-7 downregulates JNK3, mapk10-encoded protein, and p-JNK in parthenogenetic two-cell embryos from MII oocyte vitrification. TW-7 improves suppressed embryo development by reducing p-JNK expression. Furthermore, an H₂O₂ induced oxidative stress model displayed that TW-7 downregulated the expression levels of JNK3 and p-JNK probably by the antioxidant pathway. These findings suggest that TW-7 can suppress the elevated oxidative stress caused by cryopreservation, alleviate apoptosis by regulating the expression of apoptosis-related proteins like JNK3, and promote embryonic development, which provides theoretical support for the application of TW-7 in animal reproduction.