Vitamin C protects early mouse embryos against juglone toxicity.

Juglone, a naphthoquinone isolated from many species of the Juglandaceae (walnut) family, has been used in traditional Chinese medicine for centuries for its various pharmacological effects. Our previous research found its toxic effects on oocytes maturation. But we still know a little about its toxic effects on embryo development. Here, we used mouse embryo as a model to explore the effects of juglone on early mammalian embryo development. Exposure to juglone significantly decreased the development rate in early mouse embryos in vitro. Moreover, juglone exposure led to developmental arrest by disturbing mitochondrial function, producing abnormal epigenetic modifications, inducing high levels of oxidative stress and DNA damage, and increasing the rate of embryonic cell apoptosis. However, vitamin C (VC) ameliorated the toxic effects of juglone to a certain extent. Overall, juglone has a toxic effect on early embryo development through the generation of ROS and apoptosis. But VC was able to protect against these juglone-induced defects. These results not only give a new perspective on juglone's pharmacological effects on early mammalian embryo development, but also provide ideas for the better application of this agent in traditional Chinese medicine.