Novel Rat Models of Diabetic Nephropathy Displaying Pronounced Tubular Fibrosis and Glomerular Alterations

Abstract

Diabetic nephropathy (DN) is a long-term complication of diabetes characterized by proteinuria and loss of kidney function. Up to one third of patients with diabetes develop DN, and no new therapies targeting DN have been introduced for more than a decade. The lack of treatment options may, in part, be caused by the scarcity of translatable rodent models. We have established a surgically induced rat model of non-insulin dependent type 1-like diabetes (90% pancreatectomy, Px), displaying a stable blood glucose of >20 mmol/L. In addition, both Px and uninephrectomy (UNx) was performed simultaneously to potentially increase progression of renal pathological changes. Kidneys in the Px diabetic rat model displayed hypertrophy of glomeruli, cortex, and medulla 11 weeks post-surgery. Renal fibrosis was significantly increased in Px rats vs. nondiabetic control animals, as determined by quantitative histology following picro-sirius red staining of collagen (total kidney collagen, Px vs. controls; 127 ± 8 mg vs. 39 ± 5 mg, p<0.001). Plasma urea was increased in Px rats compared to nondiabetic animals (8.3 ± 0.6 vs. 5.5 ± 0.3 mmol/L, p<0.01). Finally, gene expression of the kidney injury markers NGAL and KIM1 as well as gene expression of pro-fibrotic macrophage markers (mannose receptor, MGL1, and CD163) was increased in Px rat kidneys. Px-UNx rats developed a diabetic phenotype similar to that observed in Px rats. In contrast, a highly increased kidney weight was detected with the more advanced surgical approach. Detailed histological analyses will establish whether glomerular and tubular pathology is exacerbated to a comparable extent. In conclusion, our data suggest that the Px model develops profound renal hypertrophy and fibrosis, and that renal hypertrophy is exacerbated in the Px-UNx model. Thus, Px alone and Px-UNx in rats may represent novel, strong alternatives to streptozotocin-induced diabetes and genetic models for the study of DN drug candidates. Disclosure T. Secher: Employee; Self; Gubra. Employee; Spouse/Partner; Novo Nordisk A/S. T.T. Johansen: None. M.V. Oestergaard: None. P.J. Pedersen: None. N.E. Zois: Employee; Self; Gubra. T.X. Pedersen: Employee; Self; Gubra. N. Vrang: Board Member; Self; Gubra. Employee; Self; Gubra. Stock/Shareholder; Self; Gubra. K. Fosgerau: Stock/Shareholder; Self; Novo Nordisk A/S. Employee; Self; Gubra. Stock/Shareholder; Self; Gubra. L.N. Fink: Employee; Self; Gubra. Stock/Shareholder; Self; Novo Nordisk A/S.