Abstract: Objective　 To explore the toxicity of Mycophenolic acid (MPA) on the craniofacial development of zebrafish embryos. Methods The zebrafish embryos were treated with MPA to observe the craniofacial malformation at different stages. In 72 hpf, cartilage staining was used to observe the development of craniofacial cartilage. Q-PCR was used to detect the expression level of IMPDH genes. The guanosine was added to examine its rescue of MPA-treated malformation in morphological and genetic aspects. Results MPA caused severe craniofacial malformation in zebrafish embryos. The staining results showed delayed craniofacial development and abnormal phenotype in treated embryos. Gene detection showed that the expression levels of impdh1b and impdh2 were significantly down-regulated by MPA acid. Guanosine could rescue malformation caused by MPA. Conclusion MPA can cause the craniofacial development malformation in zebrafish embryos by down-regulating the IMPDH genes which inhibits the activity of IMPDH.

Key words: Mycophenolic acid, craniofacial development, zebrafish, IMPDH pathway