Fluorospectrometer to improve GFR measurements in mice

The University of California, San Diego, Division of Nephrology/Hypertension has implemented a Thermo Scientific NanoDrop 3300 Fluorospectrometer as the fluorescent detection system for mouse glomerular filtration rate (GFR) determination.

The fluorospectrometer offers a reliable micro-volume fluorescent platform for repeated determination of GFR in conscious mice to assess their renal function without surgical procedures.

The instrument allows scientists to perform these measurements simply, quickly and cost-effectively, making the instrument a valuable tool for GFR research applications. A new application note entitled ‘Measuring Mouse GFR by Fluorescein isothiocyanate (FITC)-Inulin using the Thermo Scientific NanoDrop 3300 Fluorospectrometer,’ is available for download below.

UC San Diego’s Division of Nephrology/Hypertension considers GFR measurement to be the most reliable method in renal function assessment and the technique is used by the team to determine GFR under physiological and pathophysiological conditions in mice. In the past, the division determined GFR by measuring radioactively labelled inulin in blood plasma and urine in anesthetised animals. However, anesthesia has multiple effects on the physiology of the mammalian body and repetitive measurements are difficult to perform. As this limitation significantly impacted the study designs, the division sought an alternative method.

The division has implemented the fluorospectrometer to enable the measurement of GFR using FITC-inulin. This protocol retains the sensitivity of the traditional assay by using fluorescence detection, while the instrument’s microvolume technology has enabled researchers to reduce the volumes of blood required to <10 μl per collection time point. The NanoDrop 3300 uses a patented 'cuvette-less' sample retention system for fluorescence measurements using samples as small as 1-2 μl. This enables the division to undertake studies using serial measurements from the same model without compromising the accuracy of the GFR measurement data, or the health of the model. In addition, the easy-to-use instrument is capable of analysing multiple emission profiles from a single sample and has a small footprint, taking up minimal space in the laboratory.

Dr Timo Rieg, Assistant Professor of Medicine at UC San Diego said:

“The productivity and accuracy of GFR measurements within the Division of Nephrology has been significantly enhanced. By combining the sensitivity of the FITC-Inulin technique with the microvolume format of the NanoDrop 3300 instrument, required blood volumes have been reduced. This reduction in blood draw and the possibility to measure GFR under conscious conditions have facilitated further studies in mice that until now were not possible because of the physiological effects of anesthesia and the terminal nature of other methods of GFR determination.”

Download application note: Measuring Mouse GFR by Fluorescein isothiocyanate (FITC)-Inulin using the Thermo Scientific NanoDrop 3300 Fluorospectrometer