Standardization of renal function evaluation in Wistar rats (Rattus norvegicus) from the Federal University of Juiz de Fora's colony.

INTRODUCTION There is great interest in the use of animal models in the study of renal pathophysiology requires standardization of parameters. OBJECTIVE Standardize assessment of renal function in rats from in the Center for Reproductive Biology of Federal University of Juiz de Fora's colony. METHODS Thirty Wistar rats were used and performed measurements of creatinine (serum and urine), serum urea and proteinuria. Were evaluated: the urine collection interval in metabolic cages (24 hours or 12 hours), the need for 12-hour fast, the need of urine and serum deproteinization for creatinine measurement, need of serum deproteinization in animals with acute kidney injury to a spectrophotometer and ELISA, and the comparison of 24-hour proteinuria (PT 24 hours) with the protein/creatinine ratio (rP/C). Means were compared by the Student's t test, Pearson correlation, Bland-Altman plot for agreement and linear regression model to estimate PT 24 hours from rP/C. RESULTS The 24 hours urine output was greater than 12 hours, interfering with the creatinine clearance calculation. In the fasting group showed less water intake and lower urinary creatinine. There was great variability for the deproteinized whey and readings performed in the two devices were similar. There was a strong correlation between PT 24 hours and rP/C and the equation was generated: PT 24 hours = (8.6113 x rP/C) + 1.0869. CONCLUSION Was standardized: 24-hour urine collection without fasting. The deproteinization showed no benefit. The measurements were performed with spectrophotometer reliability. It generated a practical formula for estimating PT 24 hours through rP/C.