title: Establishing standards for studying renal function in mice through measurements of body size-adjusted creatinine and urea levels.
abstract: Strategies for obtaining reliable results are increasingly implemented in order to reduce errors in the analysis of human and veterinary samples; however, further data are required for murine samples. Here, we determined an average factor from the murine body surface area for the calculation of biochemical renal parameters, assessed the effects of storage and freeze-thawing of C57BL/6 mouse samples on plasmatic and urinary urea, and evaluated the effects of using two different urea-measurement techniques. After obtaining 24 h urine samples, blood was collected, and body weight and length were established. The samples were evaluated after collection or stored at -20°C and -70°C. At different time points (0, 4, and 90 days), these samples were thawed, the creatinine and/or urea concentrations were analyzed, and samples were restored at these temperatures for further measurements. We show that creatinine clearance measurements should be adjusted according to the body surface area, which was calculated based on the weight and length of the animal. Repeated freeze-thawing cycles negatively affected the urea concentration; the urea concentration was more reproducible when using the modified Berthelot reaction rather than the ultraviolet method. Our findings will facilitate standardization and optimization of methodology as well as understanding of renal and other biochemical data obtained from mice.
authors.affiliation: Postgraduate Course in Health Sciences, Federal University of Triângulo Mineiro, 38061-500 Uberaba, MG, Brazil ; Cefores, Federal University of Triangulo Mineiro, 38015-050 Uberaba, MG, Brazil.
authors.forename: Wellington Francisco
authors.initials: WF
authors.lastname: Rodrigues
authors.affiliation: Postgraduate Course in Health Sciences, Federal University of Triângulo Mineiro, 38061-500 Uberaba, MG, Brazil.
authors.forename: Camila Botelho
authors.initials: CB
authors.lastname: Miguel
authors.affiliation: Laboratory of Immunology and Molecular Biology, São Leopoldo Mandic Institute and Research Center, 13045-755 Campinas, SP, Brazil.
authors.forename: Marcelo Henrique
authors.initials: MH
authors.lastname: Napimoga
authors.affiliation: Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, 38015-050 Uberaba, MG, Brazil.
authors.forename: Carlo Jose Freire
authors.initials: CJ
authors.lastname: Oliveira
authors.affiliation: Postgraduate Course in Health Sciences, Federal University of Triângulo Mineiro, 38061-500 Uberaba, MG, Brazil ; Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, 38015-050 Uberaba, MG, Brazil.
authors.forename: Javier Emilio
authors.initials: JE
authors.lastname: Lazo-Chica
mesh_terms: D000818:Animals; D001830:Body Surface Area; D001835:Body Weight; D003404:Creatinine / Q000097:blood* / Q000737:chemistry; D007677:Kidney Function Tests / Q000592:standards*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012016:Reference Values; D015203:Reproducibility of Results; D013048:Specimen Handling / Q000592:standards*; D014508:Urea / Q000097:blood* / Q000737:chemistry / Q000652:urine
chemical_list: D014508:Urea; D003404:Creatinine