The toxic effect of a mixture of melamine and cyanuric acid on the gastrointestinal tract and liver in mice

•The possible toxic effects of MC mixture on gastrointestinal tract and liver were investigated.•Acute toxic study showed MC caused histopathological lesions in the gastrointestinal tract and liver.•Sub-acute study further characterized the toxic effects of MC on the gastrointestinal tract and liver.

The aim of this study was to investigate the effects of a mixture of melamine (MA) and cyanuric acid (CA) on the gastrointestinal tract and liver in mice. Kunming mice were given 0, 10, 100, or 200 mg/kg.bw/day MA and CA mixture (MC, each compound) in corn oil by gavage for 7 consecutive days. Autopsy showed severe renal injury in all MC-treated mice and histopathological examination revealed dose-related lesions in the gastrointestinal tract and liver other than the kidneys. Subsequently, Kunming mice were given 0, 0.3, 1.5, or 7.5 mg/kg·bw/day MC (each compound) in corn oil by gavage for 28 consecutive days. The results showed that higher doses of MC caused mortality and alteration on the body weights, relative liver weights, and blood chemistry parameters related to treatment. Histopathologically, the liver revealed scattered hepatic necrosis and apoptosis. Villous height and villus-to-crypt depth ratios were decreased in the duodenum and jejunum, with marked expression of proliferating cell nuclear antigen in the epithelium compared with controls. In conclusion, MC mixture could cause toxic effects in the gastrointestinal tract and liver in mice during acute and sub-acute toxicity study.