Expression of ICAM-1 on glomeruli is associated with progression of diabetic nephropathy in a genetically obese diabetic rat, Wistar fatty.

We developed an animal model for non-insulin-dependent diabetes mellitus, a genetically obese rat strain, Wistar fatty. These rats show obesity-related features such as hyperinsulinemia and hyperlipemia, and only males develop diabetic features including hyperglycemia, glucoseuria and polyuria as they age. Histopathological study demonstrated a deposition of PAS-positive granules in the epithelial cells and a diffuse thickening of the mesangial area and moderate changes of the renal tubules. We found that ICAM-1 is expressed on the glomeruli of male Wistar fatty rats and the expression is associated with the development of nephropathy; it is weak at 5 weeks, becomes markedly strong at 15 weeks and progresses further at 29 weeks of age. We tried in vivo administration of monoclonal antibody, anti-ICAM-1 alone or together with anti-LFA-1 into male Wistar fatty rats during the period from 5 weeks to 17 weeks of age. The treatment, however, could not prevent the development of nephropathy. ICAM-1 expressed on the glomeruli of Wistar fatty rats seems not to play a key role in development of the nephropathy by mediating leukocyte infiltration. It will be a useful marker of the development of the disease.