title: The true stone composition and abnormality of urinary metabolic lithogenic factors of rats fed diets containing melamine.
abstract: To better understand the toxicity of melamine to humans, the stone composition and urinary metabolic lithogenic factors of rats fed diets containing melamine including the infant's melamine-induced stone composition were studied. Sixty 4-week-old male rats divided into three groups were, respectively, fed diets containing no melamine (control), 0.1% melamine, and 1% melamine for 4 weeks. At the end of experiment, the collected stones and 24-h urines from rats were, respectively, measured with compositions and metabolic lithogenic parameters. The stone from an infant who ingested melamine-adulterated formula was also included in compositional analysis. Across three groups, the stone was only detected in 1% melamine group, with composition of almost melamine different from the affected infant's stone composed of melamine and uric acid with a ratio of 1:2. Compared with control group, urine calcium and phosphate excretions were significantly increased in 1% melamine group. Urine uric acid excretion was significantly increased but citrate excretion was significantly decreased in 0.1% and 1% melamine groups. Urine oxalate excretion and pH were indicated without any significant difference. In addition based on urine physicochemical characters, melamine-uric acid stone seems difficult to be formed in the rats due to their characters of urine high-pH and low-uric acid. These results demonstrated that (1) the stone composition of rats fed melamine was not and could not be as that of infants fed melamine-adulterated formula, two species had a different mechanism of melamine-induced stone formation; (2) the exposure of melamine could result in abnormalities of urine metabolic lithogenic factors to rats, perhaps as well as human beings.
authors.affiliation: Department of Urology, Jiangsu Province Hospital of TCM, Affiliated Hospital of Nanjing TCM University, Nanjing, 210029, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Cong
authors.forename: Xiaojian
authors.initials: X
authors.lastname: Gu
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.forename: Xizhao
authors.initials: X
authors.lastname: Sun
authors.forename: Luming
authors.initials: L
authors.lastname: Shen
mesh_terms: D000821:Animal Feed / Q000633:toxicity; D000818:Animals; D004195:Disease Models, Animal; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007223:Infant; D041943:Infant Formula / Q000737:chemistry; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D007669:Kidney Calculi / Q000139:chemically induced / Q000737:chemistry / Q000652:urine; D008297:Male; D017207:Rats, Sprague-Dawley; D012117:Resins, Synthetic / Q000633:toxicity; D014227:Triazines / Q000633:toxicity*; D014556:Urine / Q000737:chemistry*
chemical_list: D012117:Resins, Synthetic; D014227:Triazines; C011907:melamine