Quantichrom urea assay kit

Serial blood draws were performed via a retro-orbital approach and utilized to measure blood urea nitrogen (BUN) (BioAssay Systems QuantiChrom™ Urea Assay Kit Cat: (DIUR-500)), serum creatinine (Cr) (Pointe Scientific Creatinine (Enzymatic) Reagent Kit (Cat: C7548-480)), and Cystatin C (ELISA, R&D Systems, Minneapolis, MN, USA (Cat #:MSCTC0)). Additionally, urine was collected to measure KIM-1 and NGAL via ELISA (R&D Systems, Minneapolis, MN, USA (Cat #:MKM100 and MLCN20)).

BUN and SCr were assayed using a BioAssay Systems QuantiChrom™ Urea Assay Kit Cat: (DIUR-500) and Pointe Scientific Creatinine (Enzymatic) Reagent Kit (Cat: C7548-480) for the 24-h inclusion time point. Due to extensive hemolysis in the male 12-month groups, 12-month SCr in both sexes was measured using the Element DC Veterinary Chemistry Analyzer (Serial #:73110474, Manufacturer: Fujifilm, Stamford, CT, supported by Heska, Des Moines, IA) via the Comparative Pathology Core at UC Denver. Cytokines were measured by a customized U-Plex Biomarker-1 (Cat#: K15069L-S, Meso Scale Discovery, Rockville, MD) following the manufacturer's instructions as previously reported^{21 (link)}.

Serum was collected via retro‐orbital blood draw at baseline and on study Day 1 (1 day after unilateral nephrectomy), Day 27 (pretreatment), Day 29 (posttreatment), and collected at sacrifice via cardiac puncture on Day 35. Serum was processed as previously described.³¹ Urine, when available was collected noninvasively at the same time points and via bladder puncture at sacrifice on Day 35. Assays for serum BUN (BioAssay Systems QuantiChrom™ Urea Assay Kit), enzymatic creatinine (Pointe Scientific Creatinine Enzymatic Reagent Kit), cystatin C (R&D Systems, Minneapolis, MN), and urine kidney injury molecule‐1 (KIM‐1) (R&D Systems, Minneapolis, MN) and neutrophil gelatinase‐associated lipocalin (NGAL) (R&D Systems, Minneapolis, MN) were performed per manufacturer's instructions.