Metabonomic Evaluation of Melamine-Induced Acute Renal Toxicity in Rats

The recent outbreak of renal failure in infants in China has been determined to be caused by melamine (Mel) and derivatives adulterated in the food. A metabonomic study was performed to evaluate the global biochemical alteration triggered by Mel ingestion in parallel with the acute renal toxicity in rats. Mel at 600, 300, and 100 mg/kg, cyanuric acid (Cya) at 100 mg/kg, and mixture of Mel and Cya (50 mg/kg each) were administered in five groups of Wistar rats, respectively, via oral gavage for 15 days. Urinary metabonomic profiles indicated that Mel perturbed urinary metabolism in a dose-dependent manner, with high-dose group showing the most significant impact. Metabonomic variations also suggest that the toxicity of low-dose (50 mg/kg) Mel was greatly elevated by the presence of Cya (at 50 mg/kg), which was able to induce a significant metabolic alteration to a level equivalent to that of 600 mg/kg Mel. Histological examination and serum biochemical analysis also indicated that the low-dose Mel-Cya mixture and high-dose Mel group resulted in the greatest renal toxicity. The high-dose Mel and low-dose Mel-Cya resulted in disrupted amino acid metabolism including tryptophan, polyamine, and tyrosine metabolism, and altered TCA and gut microflora structure.