Melamine induces sperm DNA damage and abnormality, but not genetic toxicity

Melamine is a category III carcinogen. However, its illegal addition to milk and other protein products has led to the pet melamine poisoning in USA and infant renal calculus cases in China. Its long-term toxicity is not clear and needs to be investigated urgently to appease the public panic. In this study, the effects of melamine on mutagenesis in prokaryotes and eukaryotes were tested by Ames test, in vitro mammalian chromosome aberration test, mouse micronucleus test and sperm abnormality test; the effects of melamine on DNA damage in sperm cells were observed by single cell gel electrophoresis, and the effects on malignant transformation were examined by malignant transformation experiment of normal human liver cell line L02. The results show that melamine has no mutagenic function in prokaryotes and eukaryotes in vitro and in vivo, and does not induce malignant cell transformation after long-term exposure. However, it has ability to increase sperm abnormality rate and DNA damage.