Objective:To study the pathogenicity of Melamine in the embryonic kidney development of SD rat.Methods:40 pregnant SD rats were randomized into 4 Melamine groups and the normal control group with 8 rats per group.The rats of the 4 Melamine groups were fed the Melamine with the dosage range of 360

480

600

and 720 mg/(kg·d)

respectively.The rats of the normal control group were given 2 ml of distilled water by oral gavage per day.The concentration of Melamine was detected by enzyme-linked immunosorbent assay(ELISA) in the blood and kidneys of the newborn rats.HE staining was used to examine the histopathological change of newborn rat kidneys.Results:Melamine was found in the blood of newborn rats per group.The concentration of melamine in 600

720 mg/(kg·d) dose groups were significantly higher than that of the normal control group(P<0.05).Pathological examination showed that hyperplasia of glomerulus in the 600 mg/(kg·d) dose group

and size enlarged

The blood capillary in the renal medulla expanded with RBCs.Kidney tubular and pelvis expanded significantly.The urinary calculus and yellow precipitates were not found in kidneys of 720 mg/(kg·d) dose group.Tubules clearly expanded.Conclusion:Melamine could penetrate into fetal rats through placental barrier

and accumulate in the kidney

which may result in the injury of the growth and development of fetal rat kidney.