Experimental crescentic glomerulonephritis: a new bicongenic rat model

Crescentic glomerulonephritis (CRGN) is a major cause of human kidney failure, but the underlying mechanisms are not fully understood. Wistar Kyoto (WKY) rats are uniquely susceptible to CRGN following injection of nephrotoxic serum, whereas Lewis (LEW) rats are resistant. Our previous genetic studies of nephrotoxic nephritis (NTN), a form of CRGN induced by nephrotoxic serum, identified Fcgr3 and Jund as WKY genes underlying the two strongest quantitative trait loci for NTN phenotypes: Crgn1 and Crgn2, respectively. We also showed that introgression of WKY Crgn1 or Crgn2 individually into a LEW background did not lead to the formation of glomerular crescents. We have now generated a bicongenic strain, LEW.WCrgn1,2, in which WKY Crgn1 and Crgn2 are both introgressed into the LEW genetic background. These rats show development of NTN phenotypes, including glomerular crescents. Furthermore, we characterised macrophage function and glomerular cytokine profiles in this new strain. Additionally, we show that LEW.WCrgn1,2 rats are resistant to the development of glomerular crescents that is usually induced following immunisation with recombinant rat α3(IV)NC1, the specific Goodpasture autoantigen located in the glomerular basement membrane against which the immune response is directed in experimental autoimmune glomerulonephritis. Our results show that the new bicongenic strain responds differently to two distinct experimental triggers of CRGN. This is the first time that CRGN has been induced on a normally resistant rat genetic background and identifies the LEW.WCrgn1,2 strain as a new, potentially valuable model of macrophage-dependent glomerulonephritis.