Toxic Impairment Findings In Rat Kidney Caused By Melamine

In 2008 the event of melamine-contaminated milk caught the attention of whole nation. More attention should be paid to the child food safety. Lots of studies pointed out that intake of melamine would lead to renal stones and renal failure, the connection was seemingly uncertainty .The study results made by Beijing, Taiwan and Hong Kong investigators were discrepancy , animal test was necessary to validate the theory.Objects:This study aims to observe the renal impairment of rat after feeding melamine food, including pathologic,biochemical and ultrasonographic findings.Methods :40 SD rats were randomly divided into two groups: control group and study group (subacute impaired kidney group), 20 rats in each group. Control group was fed with routine rat food, and study group were fed with rat food fixed with melamine (2500mg/kg). After feeding for 20 days sonogram of rats'kidneys were performed, biochemical samples were tested, and eventually rats'kidneys were taken out for microscopic observation. Statistics The renal size , parenchymal thickness and parenchymal echogenity of rat kidneys in two groups were compared before and after feeding melamine food. Photoshop 9.0 was adopted to evaluate the parenchymal echogenity by the histogram function through averaging 3 samples. SPSS 16.0 was used. Measurement data were presented by mean±standard deviation. a =0. 05 was the level of test.Results:Control group showed no abnormal findings in pathology, biochemistry and sonography. In study group all 20 rats showed enhanced echoes of kidney parenchyma with multiple echogenic spots,some with stone shadow. 8 kidneys demonstrated hydronephrosis; 14 rats had urine crystals ,of which 8 had melamine crystal. 20 rats had elevated urea value(7.93~47.89mmol/L), 10 rats had elevated Cr value(134.27~178.74umol/L), and 14 rats had lower CO2CP value(12.91~19.87 mmol/L); all rats had various abnormal pathological findings, typical lesions including extensive congestion with focal bleedings in the renal tissue, spotted tubule necrosis with fibroblasts proliferation,some tubules dilated and filled with melamine crystals, several lymphocytes infiltration in some areas of renal parenchyma.Conclusion:Melamine can damage rat kidney and forms stones, resulting in renal failure.