Onset and evolution of nephropathy in rats with spontaneous diabetes mellitus

The occurrence of renal diabetic complications was studied in diabetic nono bese IIM/FmeSS (eSS) rats. The results were compared with eumetabolic Wista r rats paired by sex and age. Between 6 and 12 months of age, eSS male rats had higher fructosamine values and glucose intolerance as well as increasi ng proteinuria and uremia. Enhancement in water, calcium and phosphorus fra ctional excretion with a concomitant lower sodium excretion, was observed f rom 12 months of age on. 18- and 21-month-old eSS rats exhibited fasting hy perglycaemia and rising values of fructosamine, glucose intolerance and gly cosuria. Simultaneously, a notorious worsening of proteinuria as well as al terations in glomerular filtration were verified. Optic microscopy of 12-mo nth-old eSS rat kidneys showed areas of tubular dilatation with protein cyl inders. In 21-month-old eSS animals, kidneys appeared overtly damaged. Incr eased capsular, glomerular and Henle's thin loop diameters were verified in 12- and 21-month-old eSS rats. Glomeruli showed diffuse hypertrophy of mes angial tissue and thickening of the basement membrane. Areas of markedly at rophic and dilated tubules containing acidophilic proteinaceous material we re observed. At age of 21 months, kidneys of eumetabolic Wistar control rat s presented foci of interstitial and pielic inflammatory infiltrates.