494-P: Whole-Kidney 3D Imaging and Image Analysis Enables Detailed Quantification of Diabetic Nephropathy Features in the Uninephrectomized db/db Mouse Model

Diabetic nephropathy (DN) is a serious complication of diabetes and the leading cause of end-stage renal disease. To reproducibly test novel therapies, there is a need for precise quantification of DN pathology in rodent models. We compared the accelerated development of DN in male and female uninephrectomized db/db mice using advanced imaging techniques. Unilateral nephrectomy (UNx) was performed in 7-8 weeks old male and female db/db mice. Sham-operated db/+ mice served as controls. Kidneys were preserved for histology and stereology. In a separate study, UNx was performed in 18 weeks old male db/db mice. These mice and control db/+ mice were injected with lectin-594 prior to termination to visualize glomerular morphology by 3D light sheet microscopy. All mice were terminated at 24 weeks of age. Male and female db/db UNx mice showed comparable increases in albuminuria. Total glomerular volume was markedly higher in male and female db/db UNx mice compared to db/+ controls (mean males; 4.42 vs. 2.71 mm³; p<0.001; females; 5.04 vs. 2.69 mm³; p<0.001). Tubulointerstitial collagen III immuno-staining was significantly increased only in female db/db UNx mice compared to db/+ mice. In contrast, total glomerular collagen IV levels were increased in male db/db UNx mice compared to db/+ controls (mean 1.30 vs. 0.80 mm³; p<0.01), and female db/db UNx mice displayed increased glomerular collagen IV compared to male db/db UNx mice (mean 1.80 vs. 1.30 mm³; p<0.05). 3D imaging at 24 weeks following UNx at 18 weeks of age confirmed expansion in glomerular volume (median db/+ 96.000 vs. db/db 145.000 µm³). Moreover, a marked increase was seen in cortical lectin-594 staining, indicating glomerular leakage in db/db UNx mice.

In conclusion, male and female db/db UNx mice displayed comparable features of DN and both constitute valid models for DN. The use of whole-kidney 3D imaging provides a novel avenue for assessment of individual glomerular volume and permeability.