Transcutaneous measurement of renal function in conscious mice

Determination of glomerular filtration rate (GFR) in conscious mice is cumbersome for the experimenter and stressful for the animals. Here we report on a simple new technique allowing the transcutaneous measurement of GFR in conscious mice. This approach extends our previously developed technique for rats to mice. The technique relies on a miniaturized device equipped with an internal memory that permits the transcutaneous measurement of the elimination kinetics of the fluorescent renal marker FITC-sinistrin. This device is described and validated compared with FITC-sinistrin plasma clearance in healthy, unilaterally nephrectomized and pcy mice. In summary, we describe a technique allowing the measurement of renal function in freely moving mice independent of blood or urine sampling as well as of laboratory assays.