title: [Pathological changes in rat model of urinary calculus induced by melamine].
abstract: OBJECTIVE
  To investigate melamine-induced pathological changes in the kidney.
  
  
  METHODS
  Wistar rats were fed with a diet containing 0, 1% and 2% melamine for 15 weeks. After melamine feeding was stopped, various outcome measures were observed for 4 weeks.
  
  
  RESULTS
  Rats fed with melamine showed reduced caloric intake, slower weight gain and impaired renal function. The blood urea nitrogen of group A and B [(13.23 ± 5.10) mmol/L and (18.30 ± 5.90) mmol/L, respectively] and serum creatinine levels of group B [(19.90 ± 2.90) mmol/L] were higher than that of group C [(8.23 ± 2.30) mmol/L and (10.04 ± 1.73) mmol/L](P < 0.01, respectively). Additionally, the kidney coefficients of group A and B were higher than that of group C (P < 0.01, respectively). Crystals, tubular ectasia and interstitial inflammation and fibrosis were found in the kidneys of melamine fed rats. Four weeks after discontinuation of feeding with melamine-contained diet, the caloric intake and weight of the rats increased, the coefficients of the kidney decreased, and the blood urea nitrogen of group A and B [(17.96 ± 2.04) mmol/L and (19.20 ± 3.36) mmol/L, respectively] and serum creatinine levels of group B [(24.20 ± 5.28) mmol/L], which became worse than 4 weeks before (P < 0.01;P < 0.05, respectively), and were still higher than that of group C [(8.30 ± 1.79) mmol/L and (9.87 ± 2.71) mmol/L, P < 0.01, respectively]. Crystals remained inside the kidney, changes in the renal interstitium did not improve.
  
  
  CONCLUSIONS
  (1) Melamine-induced urinary calculus rat model can be established by feeding 3-week old male Wistar rats with a diet containing 2% melamine for 15 weeks. The main constituent of the urinary calculus was melamine (> 90%), with a little uric acid and traces of cyanuric acid. (2) Melamine damaged the renal function, formed renal crystals, and led to the pathological changes of kidneys. All the influences seemed to be dose-depended and was related with the obstruction of the crystals or calculus in the kidney. (3) The renal function and the pathological changes did not improve 4 weeks after discontinuation of feeding with melamine-contained diet.
authors.affiliation: Department of Internal Medicine, Beijing Children's Hospital Affiliated to Capital Medical University, Beijing 100045, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Shen
authors.forename: Ning
authors.initials: N
authors.lastname: Sun
authors.forename: Guan-nan
authors.initials: GN
authors.lastname: Wang
authors.forename: Le-jian
authors.initials: LJ
authors.lastname: He
authors.forename: Li-qun
authors.initials: LQ
authors.lastname: Jia
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Hong-zhan
authors.initials: HZ
authors.lastname: Xiao
authors.forename: Rui-fen
authors.initials: RF
authors.lastname: Lü
mesh_terms: D000818:Animals; D001806:Blood Urea Nitrogen; D003404:Creatinine / Q000097:blood; D004195:Disease Models, Animal; D007668:Kidney / Q000473:pathology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014227:Triazines / Q000009:adverse effects*; D014545:Urinary Calculi / Q000139:chemically induced* / Q000473:pathology*
chemical_list: D014227:Triazines; D003404:Creatinine; C011907:melamine