Renal effects of excessive fructose intake in Spontaneously Diabetic Torii-Leprfa (SDT fatty) rats

Excessive fructose intake has been reported to increase the risks of obesity, diabetes and kidney diseases, including diabetic nephropathy. We investigated the effects of a high-fructose diet on nephropathy in both male and female Spontaneously Diabetic Torii-Lepr^fa (SDT fatty) rats, a model for obese type 2 diabetes. 11-week-old male and female Sprague-Dawley (SD) and SDT fatty rats that developed diabetes were each divided into 2 groups receiving either a high-fructose diet (60% fructose) or a basal diet. The diets were fed ad libitum for 7 weeks. Body weights, food consumption, clinical chemistry, urinalysis, kidney weights and histopathology of the kidneys were evaluated. In the SDT fatty rats, fructose intake increased the urinary excretion of calcium and inorganic phosphate in both sexes. Histopathological examination revealed that fructose intake worsened nephropathy (mineralization, inflammatory cell infiltration, and increased mesangial matrix in the glomeruli) in the female SDT fatty rats. In conclusion, a 7-week high-fructose diet induced several renal changes in SDT fatty rats, including urinary electrolyte imbalances and associated mineral deposition in the kidney, suggestive of urinary stone formation. It suggests that the SDT fatty rat is a useful model to investigate type 2 diabetes and diabetic nephropathy and that excessive fructose intake can be a risk factor for the development and progression of urinary stone formation and diabetes- related kidney injury.