title: Ageing mouse kidney--not always the SAME old story.
abstract: BACKGROUND
  As interest in the ageing kidney grows rapidly, more experimental ageing studies are conducted in the field. One of the main obstacles that researchers have to face is that studies in old animals are often less reproducible than in young animals. We have observed that the aged animal's provenance can be an overlooked factor accounting for such experimental heterogeneity.
  
  
  METHODS
  Male C57BL/6J mice aged 19-22 months were purchased from four different suppliers. Baseline renal parameters were evaluated by measuring serum urea, serum creatinine and proteinuria. Renal morphology was analysed by quantifying glomerulosclerosis, interstitial fibrosis and amyloid deposits on paraffin sections stained with PAS, Masson trichrome, Sirius red and Congo red.
  
  
  RESULTS
  We found normal renal ageing in mice from three sources, but an unexpected renal pathology in mice from one major European supplier. Mice from this supplier had significantly elevated serum urea, creatinine values and an increased urinary protein excretion. Corresponding kidneys displayed massive glomerulosclerosis with evidence of amyloid deposits and increased interstitial fibrosis.
  
  
  CONCLUSIONS
  Supplier-dependent differences, such as observed here, can explain irreproducibility of experimental results in renal ageing research. This can be avoided by careful baseline analysis prior to in vivo experiments.
authors.affiliation: Department of Nephrology, Hannover Medical School, Hannover, Germany. schmitt.roland@mh-hannover.de
authors.forename: Roland
authors.initials: R
authors.lastname: Schmitt
authors.forename: Christoph
authors.initials: C
authors.lastname: Jacobi
authors.forename: Nathan
authors.initials: N
authors.lastname: Susnik
authors.forename: Verena
authors.initials: V
authors.lastname: Broecker
authors.forename: Hermann
authors.initials: H
authors.lastname: Haller
authors.forename: Anette
authors.initials: A
authors.lastname: Melk
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D007668:Kidney / Q000033:anatomy & histology / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL