Abstract: SA-PO319

Development of a Refined Subtotal Nephrectomy Mouse Model to Study Progressive Renal Disease

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 308 CKD: Mechanisms of Tubulointerstitial Fibrosis

Authors

  • O'Sullivan, James, University of Edinburgh, Edinburgh, United Kingdom
  • Finnie, Sarah L, University of Edinburgh, Edinburgh, United Kingdom
  • Denby, Laura, University of Edinburgh, Edinburgh, United Kingdom
Background

Chronic Kidney Disease (CKD) is characterised as the decline of renal function over time. Metabolomics data has elucidated new metabolites, including citrulline, to be associated with human CKD indicating alterations in metabolic pathways being involved in CKD [Rhee EP et al, 2013]. Furthermore, defective fatty acid oxidation has been found to be involved in tubulointerstitial fibrosis [Kang HM et al, 2015]. The rat subtotal nephrectomy (STNx) model is a commonly used model of progressive renal disease and replicates many aspects of human CKD. However, a consistent mouse model of STNx which mimics most of the typical features of CKD would be advantageous to elucidate the pathophysiology.

Methods

Inbred 129S2/SvHsd mice were randomised to sham or one-step subtotal nephrectomy (STNx) surgery and sacrificed after 6 (n=6/gp) or 10-weeks (n=8-9/group). The one-step STNx involves flank incision nephrectomy followed by flank incision removal of upper and lower poles of the remaining kidney. At sacrifice, tissue was taken for RNA, protein and histological analyses. At baseline, 6 weeks and 9 weeks animals had urine collected and echocardiography performed. Blood pressure (BP) was measured by tail cuff plethysmography (baseline and 9 weeks). Gene expression was determined via qRT-PCR and normalised to 18S/PPIA. Fibrosis scoring was conducted using picrosirius red staining for total collagen, quantified in ImageJ.

Results

This refined STNx model had a survival rate of 95%. At 10 weeks post surgery STNx animals had significantly increased systolic BP (Sham: 110+/7.8 vs STNx: 153.1+/-13.8 mmHg), significantly increased urinary albumin:creatinine ratio (p<0.01; 16.37 vs 2028.5 mg/g; sham vs STNx) and developed left ventricular hypertrophy (LVH) (1.4-fold increase STNX vs SHAM). Histological analysis revealed a significant increase in renal and cardiac fibrosis in STNx mice vs sham which was reflected by 2-fold increase in collagen gene expression (p<0.01 vs sham). Additionally, gene expression of metabolic pathways was downregulated in STNx kidneys and heart (p<0.05 vs sham).

Conclusion

Our refined STNx model is a robust model of progressive renal disease that develops significant hypertension, proteinuria, renal and cardiac fibrosis, LVH and alterations in cellular metabolism indicating this model reflects the cardio-renal dysfunction observed in human CKD.