Placental transfer of melamine and its effects on rat dams and fetuses

In 2008, an epidemic of cases of renal failure among Chinese infants, due to melamine contamination of milk, raised international concern. Thus, numerous studies on the metabolism of melamine were broadly undertaken. However, little is known about placental transfer of melamine. In this study, the possibility of placental transfer of melamine and its effects on fetuses and pregnant dams were determined. Melamine was respectively administered at 0, 40 and 400 mg/kg body weight by daily gavage from gestation day (GD) 13 to GD 20 to control (C), low melamine (LM) and high melamine (HM) groups of pregnant female F344 rats. Rats were sacrificed 30 min after the last gavage. Melamine was not detected in any of the control and placental samples, or in amniotic fluid from the LM group. Plasma and fetal melamine concentrations in the HM group were significantly higher than in the LM group (P < 0.01). Liver enzyme determination revealed no differences among the three groups. However, plasma creatinine, plasma uric acid and blood urea nitrogen concentrations in dams were significantly increased by melamine (P < 0.05). These results show that ingested melamine affects renal function in dams and dose-dependently passes the placental barrier to reach the fetus.