Isolated perfused rat kidney: a technical update.
The isolated perfused kidney is commonly utilized as a screening tool for renal clearance and metabolism, and to correlate renal drug deposition to renal function. Here, we report on several aspects of this procedure that will facilitate a higher experimental success rate and lead to a reduction in animal use. First, we investigated the utility of inulin and creatinine as commonly used markers to measure glomerular filtration rate. For inulin, in the presence of either 20 mM glucose or 4.5% dextran in the buffer, significant interference was observed using an anthrone-based colorimetric assay. These findings suggest that caution needs to be exercised when using glucose or dextran and when inulin is quantitated using this method. Under these circumstances the use of alternative methods of inulin quantitation such as fluorescently tagged inulin is preferred. Second, we optimized bovine serum albumin (BSA) and BSA/dextran compositions that are routinely recommended as oncotic agents in the perfusion buffer and found that a 4% BSA/1.67% dextran composition had the best viability of kidney biomarkers in accordance with recommended threshold parameters. These considerations will be of particular relevance to researchers utilizing the isolated perfused kidney as a screening tool to measure renal biology and drug metabolism as well as applications to investigate diabetic nephropathy.
School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
Hao-Han
HH
Chang
Bernard
B
Choong
Anthony
A
Phillips
Kerry M
KM
Loomes
D000818:Animals; D003404:Creatinine / Q000378:metabolism; D003911:Dextrans; D003928:Diabetic Nephropathies; D005919:Glomerular Filtration Rate; D005947:Glucose; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism; D007668:Kidney / Q000378:metabolism / Q000502:physiology*; D008297:Male; D010477:Perfusion; D051381:Rats; D017208:Rats, Wistar; D012710:Serum Albumin, Bovine; D014022:Tissue Survival
D003911:Dextrans; D007328:Insulin; D012710:Serum Albumin, Bovine; D003404:Creatinine; D005947:Glucose