FOCAL GLOMERULAR SCLEROSIS IN FAWN-HOODED RAT

  • 1 January 1978
    • journal article
    • research article
    • Vol. 92  (3) , 637-+
Abstract
The fawn-hooded [FH] rat develops pathologic features similar to those observed in steroid-resistant focal glomerular sclerosis, i.e., by light microscopy some of the glomeruli appear normal but others show areas of solidification confined to 1 or 2 lobules of the tuft. The pathogenesis of this disease was not well known and there was a great need for an animal model. In the FH animal, a marked difference in the development of the lesion was noted between male and female rats. Fifty percent of 4 mo. old males had proteinuria in excess of 10 mg/day (none of the females had significant proteinuria), while all 12 mo. old males had proteinuria in excess of 45 mg/day (female 12 mo. old FH rats had mean proteinuria of 7 mg/day). At 6 mo. of age continuing through 12 mo. of age, male FH rats had mesangial deposits of Ig[immunoglobulin]G, IgM and, occasionally, C3 [complement component 3], demonstrable by immunofluorescence, whether or not FGS was present. Subepithelial electron-dense deposits were never seen by EM either at 6 or 12 mo. Six mo. old animals frequently did not exhibit FGS. Instead, the glomerular epithelial cells exhibited fusion of food processes, vacuolization and, in some areas, focal loss of the epithelial covering on the glomerular basement membrane (GBM). Six mo. old males with proteinuria exhibited focal loss of negative charge from all layers of the filtration barrier. The GBM from sclerotic glomeruli of 12 mo. old rats was commonly denuded of epithelium. None of the animals in this study was uremic. FH rats demonstrated FGS associated with progressive glomerular epithelial cell injury.